{~11}??- xéa‘w‘nwi‘; “2‘.“ 33'?!

I
4'

'l

"’vl
-"’4i‘ i:I"" *ll‘
‘I' V

  
  

- ““1 ‘|

53%

   
  

f l
‘k " , ilimtii' " of? 'III'“
, I
”a. j: i.

Q" , W51"
.. I

  
  
 

  

   
  

 
 

  

 

‘qk
1253”
'1) gis'; 1... . ‘) ygfia’a“ J::‘,‘N'. ~"
V ~ r-zn' M‘ibm‘vm’ "’ ‘ mg :5.
H.“ 4%. .,1\\ ‘31:???
‘ fifl?‘ I .4135}. o
A?!
a\‘ll‘bl-P'¢. .‘ZI ". w
T: .- ifi‘nlt.) n- _ I

    

u a;

 
 
    
      
  

T‘iltn
IIKI'II, 'r‘fz
I‘J'“ u“. “' ‘ 1
IV. I‘I'“ ',\.'y ‘:‘.T': ‘I
4;" If": ;'/I:< I'll!

   

m rl'f'vt‘z‘L': I
. ”“1 Hath-fl» “div-T” '3"

“.105" "“4"”

   
  
  

  
 

 

     
   
        
     

 

 

 

I'. . ‘.“'
i'._“n .‘ ‘- L__‘,‘

"'V'
0‘ he"! i‘:;1~"

i . I

  
   

.1 "'l|i iii-[Iii i ‘Iii ”“in1 ii“ l-.‘

i I Iii .. ii'i H
' I". "v I: i' F" 'It 'i 7" I ‘ .Jilll" Inn“ U':II:‘|~I" .l'. {'51...‘ :Iilt' *ldi lIII Ifi'.“
I’m“ i”: . ”I“ “LipifliruHI III-ii lil. I-f‘fi {W ”Hi. mm 1631‘. MW at“) humm- Em. . ”I

  

“it!!!

 

This is to certify that the

thesis entitled

GENETICS 0F BODY WEIGHT 0F
RING-NECKED PHEASANT (PHASIANUS COLCHICUS) POPULATION

presented by
JOHN FARAJ KASSID

has been accepted towards fulfillment
of the requirements for

Ph.D. Animal Science

 

 

degree in

:ng 7% 63.3%“

Major professor

Date ill? 7,/?/

0-7 639

 

‘ .i i OVERDUE FINES:
Ln, _ , “ 25¢ per day per item
[A 5%}; j RETURNING LIBRARY MATERIALfi:
,2”- ~.E.>,”2' =4 Place in book return to venom
s" “"1" ‘« charge from circulation recor

 

 

 

 

GENETICS OF BODY WEIGHT 0F
RING-NECKED PHEASANT (PHASIANUS COLCHICUS) POPULATION

By
John F. Kassid

A DISSERTATION

Submitted to
Michigan State University
in partial fulfillment of the requirements
for the degree of
DOCTOR OF PHILOSOPHY

Department of Animal Science

1981

6 //é 9’9é

ABSTRACT

GENETICS OF BODY WEIGHT OF
RING-NECKED PHEASANT (PHASIANUS COLCHICUS) POPULATION

By John F. Kassid

In a population of Ring-Necked Pheasants (Phasianus
colchicus) a divergent selection program was initiated for
high and low twelve-week body weight. Data were collected
from 8 sires, 59 dams, and 1197 offspring over a period of
two generations.

Divergent selection for 12-weeks weight has resulted
in mean body weight differences of about 2, 49, 168, 283 and
381 gm in the males and 2, 54, 156, 264 and 327 gm.in the
females at one-day, 4-weeks, 8-weeks, 12-weeks and lB-weeks of
age, respectively, between the two divergent selected lines.

The heavy selected line gained more weight by plus
selection than was lost from the light selected line by minus
selection. The males gained or lost more weight than females.

Experimental data transformation to logarithmic and
percentage scale did not appear to gfiyea noticeably better
fit than the actual scale. Thus there was little evidence
that size genes were acting multiplicatively.

Average heritability estimates for the first genera-
tion of selection calculated from parent-offspring regression

techniques after omitting all values that fall outside the

John F. Kassid
possible biological range of heritability were found to be
.47 T .1, .44 T .08, .66 T .07, .50 T .04 and .63 T .03 for
body weights at one-day, 4-weeks, 8-weeks, 12-weeks, and
18-weeks of age, respectively. Heritability estimates for
the second generation heavy selected line at these time
intervals would be .29 T .18, .64 T .21, .46 T .24, .77 T .26
and .33 t .16, respectively, while for the second generation
light selected line they were equal to .47 t .42, .59 t .24,
.41 T .23, i .20 T .42 and .59 T .03, respectively.

Average realized heritability estimates for lZ-weeks
body weight after negative heritability estimates were omitted
from the statistical analysis were found to be .50 and .33 in
males and females of the light selected line, respectively,
while they were equal to .71 and .38 in the heavy selected
line for males and females, respectively.

These results suggest the existence of high additive
genetic variance, which in turn indicate that mass selection
would be the best single procedure to use to select for body
weight.

Duration of fertility ranged from 10-21 days with an
average of about 15 days.

An average of 0.82 for'the degree of coefficient of
correlation between egg weight and day-old chick weight was
calculated. Chick weight at hatching time was found to
represent 64-67 percent of the weight of the egg from which
it hatched.

Hen-housed egg production for the heavy females

selected as parental stock was 60.63 and 48.57 percent for base

John F. Kassid
and first generation, respectively. For the light selected
females it was 48.83 and 34.19 percent for the same genera-
tions, respectively. Hen-day egg production for heavy
females selected as parental stock was 61.87 and 51.61 per-
cent for base and first generation, respectively. For the
light selected females it was 56.70 and 39.66 percent for the
same generations, respectively.

Percent mortality was 19.58, 31.93, 37.03 and 24.20
for the base, first, second generation and control population,
respectively. Chi-square analyses indicate that mortality is
not independent of selection. Highly significant differences
(p < .01) in mortality were found between base generation and
first generation, base generation and second generation and,

finally, between control and second generation.

To my daughter

Rana

ACKNOWLEDGEMENTS

The most sincere gratitude, appreciation and indebted-
ness must go to my major professor, Dr. Theo H. COleman who
assisted me with guidance, inspiration, patience and numerous
helpful suggestions with the preparation of this manuscript
and also throughout the entire period of my graduate study at
Michigan State University.

Special thanks are extended to Dr. William T. Magee
and Dr. Cal J. Flegal, who served on my graduate committee and
provided valuable constructive review of this dissertation.

The writer expresses gratitude to the government of
Iraq for the generous financial support during the tenure of
his graduate program.

The author also expresses heartfelt appreciation to
his family for their continuous encouragement and sacrifices
during the entire course of his study.

Finally, I am.grateful to my wife, Shatha, for her
unwavering cooperation, patience, devotion and encouragement
which helped me achieve my educational goal.

Also, thank you to Mrs. Joy Walker for her typing of

this dissertation.

ii

TABLE OF CONTENTS

INTRODUCTION .
REVIEW OF LITERATURE .

Body weight . .

Sexual dimorphism .

Phenotypic variation .

Selection experiments .

Divergent selection experiments

Selection limit .

Heritability .

Methods of estimating heritability

Heritability estimates of body weight in.
chicken . .

Heritability estimates of body weight in
turkey

Heritability estimates of body weight in.
other species of poultry . . . .

Genetic and phenotypic correlation

MATERIAL AND METHODS '
RESULTS AND DISCUSSION .

Effect of selection .
Heritability estimates
Duration of Fertility .

Relationship of egg weight to chick weight.

at hatching .
Egg production .
Mbrtality and Cause of Death

SUMMARY AND CONCLUSIONS

BIBLIOGRAPHY °
APPENDICES .

iii

hudrdhi 'o
chnnnacnonbLo i» P' m
m

21
30

33
35

42
53
53
63
75
76
81
84
88

107

LIST OF TABLES

Table Page

1 Mean body weights (gm) at one-day, 4-weeks,
8-weeks, lZ-weeks and 18-weeks of age for
base, first and second generation and the
control population of the light selected
line of Ring-Necked pheasants . . . . . . 54

2 Mean body weights (gm) at one-day, 4-weeks
8-weeks, 12-weeks and l8-weeks of age for
base, first and second generation and the
control population of the heavy selected
line of Ring-Necked pheasants . . . . . . 55

3 Average one-day old weights (gm) of male
and female Ring-Necked pheasants of the
base generation and after two generations
of plus selection in the heavy line and
minus selection in the light line.
Gains and losses expressed in absolute
grams, in differences of logarithms of
weights, and in percentages . . . . . . . 64

4 Average 4-week weights (gm) of male and
female Ring-Necked pheasants of the
base generation and after two generations
of plus selection in the heavy line and
minus selection in the light line.
Gains and losses expressed in absolute
grams, in differences of logarithms of
weights, and in percentages . . . . . . . 65

5 Average 8-week weights (gm) of male and
female Ring-Necked pheasants of the base
generation and after two generations of
plus selection in the heavy line and
minus selection in the light line.

Gains and losses expressed in absolute
grams, in differences of logarithms of
weights, and in percentages . . . . . . . 66

6 Average 12-week weights (gm) of male and
female Ring-Necked pheasants of the base
generation and after two generations of
plus selection in the heavy line and minus

iv

LIST OF TABLES (Continued . . .)

10
ll

12

13

selection in the light line. Gains

and losses expressed in absolute grams,
in differences of logarithms of weights,
and in percentages . .

Average 18-week weights (gm) of male
and female Ring-Necked pheasants of the
base generation and after two generations
of plus selection in the heavy line and
minus selection in the light line.
Gains and losses expressed in absolute
grams, in differences of logarithms of
weights, and in percentages .

Heritability t standard error as esti-
mated by regression of offspring weight
on dam, sire and mid-parent 5 weight at
one day, 4-weeks, 8-weeks, lZ—weeks and
18-weeks of age, respectively, for the
first generation, second generation
heavy selected line and second genera-
tion' light selected line, respectively.

Selection responses, selection differ-
entials and realized heritability esti-
‘mates of body weights for 12-week old
males and females of the light and

heavy selected lines for the first,
second and both generations of selection,
respectively .

Duration of fertility

Summary of egg weight to day- -old chick
weight relationships . . . . . . .

Hen-housed and hen-day egg production
for base and first generation females
selected as parental stock .

Number of birds hatched, survived,
died and percent mortality for the
total period of the eXperiment (October 1
l974-March 2, 1977)

67

. 68

73
77

79

82

. 82

Figure

LIST OF FIGURES

The effect of selection for 12-week body
weight on one day body weight . .

The effect of selection for 12-week body

weight on 4-week body weight

The effect of selection for lZ-week body
weight on 8-week body weight . .

The effect of selection for lZ-week body
weight on 12-week body weight . .

The effect of selection for 12-week body

weight on l8-week body weight .

vi

. 6O

. 61

. 62

Table

LIST OF APPENDICES

Composition of the pheasant starter ration
(fed 0-6 weeks of age) in percentage .

Nutrient composition of the pheasant starter
ration based on calculated analysis

Composition of the pheasant grower ration
(fed 6-13 weeks of age) in percentage

Nutrient composition of the pheasant grower
ration based on calculated analysis

Composition of the pheasant flight ration
(fed 13 weeks of age until time of lighting)
in percentage . . . . . . .

Nutrient composition of the pheasant flight
ration based on calculated analysis . .

Composition of the pheasant breeder ration
(fed after time of lighting) in percentage .

Nutrient composition of the pheasant breeder
ration based on calculated analysis .

vii

. 109

. 110

. 111

112

. 113

. 114

INTRODUCTION

Selection is considered to be the best tool for
genetic improvement in a given population. The basis for
genetic improvement achieved by selection in any population
will be due to the genetic variation within that population.
If most of the gene action is of the additive type, indivi-
dual phenotypic selection should be effective in changing
the population means for this characteristic in either an up-
ward or downward direction; on the other hand if dominance
and epistasis constitute much of the genetic variation then
aids to mass selection are recommended (i.e. progeny, sib
test).

Heritability of a character is an important factor
affecting genetic improvement. Accurate estimates of herit-
abilities of economic traits are needed in poultry breeding
practices for the formulation of efficient selection schemes
to ensure that the highest genetic gains are obtained.

Many estimates of heritability have been reported
for body weight in poultry, a trait which is frequently
considered as the most important one in breeding programs
directed toward the improvement of meat type birds. From
these estimates it would be logical to conclude that body

weight has a moderate to high heritability.

2

In single trait selection experiments, simultaneous
changes in unselected traits as a result of selection for
one particular trait are termed correlated responses. The
genetic cause of correlation is chiefly pleiotropy which
results in more permanent genetic correlations, though link-
age is a cause of transient correlation (Falconer, 1960a).

The primary objective of this study was to accumulate
additional empirical knowledge on size inheritance in Ring-

lbcked pheasants.

REVIEW OF LITERATURE

Body weight

Body weight, which is considered as one of the typi-
cal multifactorial or polygenic traits and one of the most
important inherited traits in the fowl, was studied by many
investigators over the past 50 years in order to determine
its genetic make-up and to establish certain genetical tech-
niques to improve it.

Many reports have been published concerning the
number of genes that control this trait. Asmundson and Lerner
(1933), Knox and Marsden (1944) and Hurry and Nordskog (1953)
demonstrated that inherited differences in body growth were
affected by multiple genetic factors, the exact number of
which has not yet been determined exactly. On the other hand,
Festing and Nordskog (1967) reported that body weight is con-
trolled by both independent and pleiotropic genes.

Goodale (1938) reported that at least 32 pairs of
genes were responsible for the heaviest mice that he obtained
in his experiment on the inheritance of body weight in the
albinO‘mouse.

Falconer (1953a) gave an approximate estimation of
the minimum number of loci which affect weight in a random
population of mice to be equal to at least nineteen loci on

the assumption that

4

1) All genes concerned have equal effects.

2) All genes concerned act additively both within

loci and between loci.

3) The alleles at all loci have frequencies of .5.

Data from.MacArthur's experiments (1944a, b, 1949)
were used by Falconer (1953a) who reported a much higher
estimation of the minimum.number of loci which affect weight,
being equal to at least fifty-four loci. Godfrey (1953)
reported that one sex-linked gene and at least fifteen pairs
of autosomal genes affect growth rate prior to 9 weeks of
age in domestic fowl and thereby influence mature body size.

MacArthur (1944a) elaborated on the geometric theory
of size-gene interaction that size genes or modifiers act
geometrically by multiplying rather than summing each other's
effects. Falconer (1953a) stated from his selection experi-
ment for large and small size in mice that size genes act
multiplicatively on an arithmetic scale while they act on a
logarithmic scale additively.

Body weight is also affected by environmental factors
due to genetic-environmental interactions. The preponderance
of the genetic part is due to the presence of polygenes where
many genes are present which have minor effects (Hurry and

Nordskog, 1953).

Sexual dimorphism

 

Reports by Asmundson (1942); Knox and Marsden (1944);
Asmundson (1948); Hutt (1949); Knox 35 31. (1952); Siegel (1962a);

5
Washburn and Siegel (1963); Marais and Joubert (1964);
Kinney and Shoffner (1965); Nestor gt a1. (1967);
Buvanendran (1969) and Sefton and Siegel (1974) on sexual
dimorphism show that almost all domesticated avian species
show sexual dimorphism for body size.

Marais and Joubert (1964) stated that in the Muscovy
duck, the male is about twice the size of the female. On
the other hand, Siegel (1962a) reported that in the fowl the
male is about 10-15 percent heavier than the female.
Asmundson (1942) and Knox and Marsden (1944) stated that
turkey female's weight is 65 and 66 percent as much as the
male's, respectively.

Sefton and Siegel (1974) reported from their study
on inheritance of body weight in Japanese quail that sexual
dimorphism became evident at the age of sexual maturity with
females being heavier than males. This difference is due to
the fact that increase in total body weight is associated
with the reproductive maturation and the large female repro-
ductive system. Hutt (1949) stated that "the differences in
the size of male and female fowls are apparently determined
by sex-linked genes, of which the males, with two sex
chromosomes must have more than the females, which have only
one sex chromosome."

Buvanendran (1969) reported from his work on the
sexual dimorphism for lO-week body weight of White Leghorns

that the genetic correlation between male and female weights

6

was .586 t .170. He stated that this figure is an indica-
tion of a considerable genotype-sex interaction. Similar
results were obtained by Kinney and Shoffner (1965) who
reported a value of .66 t .08 for the genetic correlation
between 8-week body weight of males and females. From these
findings, Kinney and Shoffner (1965) stated that 8-week body
weight of the males and the females should not be considered

as the same trait.

Phenotypic variation

 

The phenotypic variation observed in any trait (i.e.
body weight) can be divided into hereditary and non-hereditary
variation. The hereditary variation can be partitioned still
further according to the nature of the genic effects, into
the additive genetic variation, which is contributed by the
average effects of genes in any combination with other genes
(Lush, 1940), and the non-additive genetic variance which is
contributed by interactions of genes. These interactions can
be either from dominance (interaction between allelic genes)
and/or epistasis (interaction of non-allelic genes). Develop-
ment of this partitioning concept was largely due to Fisher
(1918), Wright (1921), Fisher 3; 31. (1932) and Wright (1935).

Several investigators have attempted to determine the
relative importance of non-additive genetic effects on body
weight. Among those who reported evidence of the non-additive
variance contribution to the total variability of body weight

are Moyer gt 31. (1962) and Mahmoud gg_al. (1965), while

7
Yao (1959, 1961) reported significant dominance effects in
certain incrosses and incrossbreds.

On the other hand, many researchers failed to show
the existence of non-additive genetic variation in body
weight genetic architecture (Hazel and Lamoreux, 1947;

Martin gg_gl. 1953; Brunson g5 El. 1956; Chai, 1956;
Goodman 2; El- 1957; Kan g; al. 1959b; Goodman and Jaap,
1960; Comstock gg El- 1963; Miller gt_§1. 1963 and Silva
gg El. 1976).

Diallel mating as a method of studying non-additive
genetic variance was used in excellent experiments that were
carried on by Hayman (1954a, b); Jinks (1954); Dickinson and
Jinks (1956); Griffing (1956); Kempthorne (1956). These ex-
periments were confined mostly to plant material, and they
will be of great benefit to refer to mainly in case of examin-
ing the effect of non-additive genetic variance.

Influence of sex-linked genes and maternal effect on
the inheritance of body weight was examined in different pub-
lished reports. The reports of Godfrey (1953); Brunson 35 El.
(1956); Jaap and Crimes (1956); Jerome 35 a1. (1956); Newcomer
(1957); Thomas 25 31. (1958); Hutt (1959); Kan 55 gl. (l959a,b);
Merritt (1966) and Joubert 33 31. (1974) indicated that
sex-linked genes may be of considerable importance in the
inheritance of body weight, while reports of Hazel and
Lamoreux (1947); Shaklee $5.31. (1952) and McCartney (1955)
overlooked the effect of sex—linkage, by stating that sex-linked

genes have no influence on body weight.

8

Maternal effects have been investigated by several
workers (Hazel and Lamoreux, 1947; Bumgardner and Shaffner,
1954; Brunson gg‘gl. 1956; King, 1961; Yao, 1961; Friars g£_§1.
1962;'Moyer 2; El, 1962; Merritt, 1966; Shimizu gg’al. 1968;
and Joubert g; 51. 1974) who demonstrated that maternal influ-
ence has an effect on body weight, and on heritability esti-
mates. Contrary to that, Jerome 35,31. (1956) reported from
their work with New Hampshires that for fall body weight the
heritability calculated from the sire variance component ex-
ceeds that calculated from the dam component. These results
suggest that maternal effects contribute little or no addi-

tive genetic variance.

Selection experiments

 

Review of literature revealed a considerable amount of
selection experiments which have been performed by numerous
researchers over the past years to investigate the effect of
selection and to estimate realized genetic parameters needed
frequently in animal breeding research and practice. Fisher
(1918); wright (1921); Fisher (1930); Wright (1931); Haldane
(1932) and Lush (1945) have developed the theory upon which
much of these estimates were primarily based.

Many selection experiments have been conducted to
study the inheritance of body weight. The results of these
experiments have contributed significantly to our present know-
ledge and understanding of the genetic phenomena involved.

It is impossible to list all the publications dealing with

9
body weight selection experiments and their statistical
analyses procedures, but a review of the most important
papers that would be of primary interest will be given.
Among papers that have been designed to discover the mode
of body weight inheritance and those that have dealt with
the statistical investigations of the subject are those of
Goodale (1938, 1941); Hazel and Lush (1942); Hazel (1943);
MacArthur (1944a,b); MacArthur and Chiasson (1945); MacArthur
(1949); Mather and Harrison (1949); Lerner and Dempster (1951);
Falconer and Latyszewski (1952); Falconer (1953a, b);
Falconer and King (1953); Kyle and Chapman (1953); Martin
25 El- (1953); Clayton gt 31. (1957); Osborne (1957); Mode
and Robinson (1959); Young (1961); Nordskog and Festing
(1962); Robertson (1962); Siegel (l962a,b); Abplanalp gt El.
(1963); Maloney 25 al. (1963a, b); Rahnefeld gg a1. (1963);
Siegel (1963a, b); Nordskog £2 a1. (1964); Gill (1965a, b, c);
Magee (1965); Searle (1965); Bohren 3E 31. (1966); Gaffney
(1966); Gill and Clemmer (1966); Ideta and Siegel (1966a, b);
Maloney and Gilbreath (1966); Merritt g3 El. (1966); Roberts
(1966a, b); Festing and Nordskog (1967); Kinney and Shoeffner
(1967); Maloney g£_§l. (1967); Roberts (1967a, b);
Richardson gE 31. (1968); Shimizu g3 El. (1968); Parker ggigl.
(1969); Hill (1970); Merat (1970); Mukherjee and Friars (1970);
Parker 25 al. (1970a, b); Hill (1971); Burrows (1972); Hill
(1972); Becker and Bearse (1973); Cheung and Parker (1974);
Hill and Nicholas (1974); Nordskog §E_§l. (1974); Berger and
Harvey (1975); Bruns and Harvey (1976); Marks (1978) and
Siegel (1978).

10

Collectively, these selection experiments have shown

that

1) Selection is an effective force in changing the
mean of the population over many generations,
either upward or downward, until all desired genes
are fixed.

2) Alternating periods of changes for several genera-
tions due to selection which have been followed
by generations of little or no change, were
observed in some of these experiments.

3) Selection is a slow process in changing the mean
of the population.

4) Effect of selection is permanent.

5) Heritability estimate remains substantially un-
altered by continued selection.

6) Environmental, epistatic and dominance effect will
impede progress due to selection.

This discrepancy between expected and observed genetic changes
led wyatt (1954) to question the magnitude of the heritabil-
ity estimate, since selection continues to be effective until
all desired genes are fixed. Genetic slippage was the term
used by Dickerson (1955) to describe the situation where the
observed genetic gain falls below the expected genetic gain,
where he attributed this genetic slippage to possible inter-
environmental (i.e. adverse environmental time trends and

genotype-environmental interaction) and intra-environmental

11
(i.e. lower heritability, reverse mutation and inbreeding)

factors.

Divergent selection experiments

 

In poultry, measurement of the direct and correlated
responses to selection for body weight have been achieved
either throuth two-way selection (that is, starting from the
base population, selecting the high and low line to represent
the right and left-hand tail of the phenotypic distribution
respectively) or one-way selection, where the response will
be measured as a deviation from a genetically controlled line.

Some reports have been published on divergent selec-
tion for body weight (Schnetzler, 1936; MacArthur, 1944a, b;
MacArthur and Chiasson, 1945; MacArthur, 1949; Godfrey and
Williams, 1952; Falconer, 1953a, b; Godfrey and Goodman, 1955;
Falconer, 1954; Clayton 3p a1. 1957; Schierman gp’al. 1959;
Falconer, 1960b; Maloney and Gilbreath, 1962; Nordskog and
Festing, 1962; Siegel, 1962a, b; Maloney 25 El. 1963a, b, c;
Siegel, 1963a, b; Ideta and Siegel, 1966a, b; Maloney and
Gilbreath, 1966; Festing and Nordskog, 1967; Maloney 25 El-
1967 and Carte and Siegel, 1968).

In general these experiments have indicated that:

l) Asymmetrical response was more commonly observed
than uniform response in divergence between heavy
and light lines, where heavy line gained more
weight by plus selection than was lost from light

line by minus selection.

12

2) Positive regression was obtained, where heavy
parents produced heavy offspring and light
parents produced light offspring.

3) Selection was effective in producing considerable
change in two-way directions over many genera-
tions with and without inbreeding.

4) Overlapping between the heavy and light lines
practically ceased after the sixth generation of
practicing divergent selection (MacArthur, 1944a).

5) Crosses between heavy and light line individuals
resulted in offspring that were intermediate
between the parents.

6) Males gained or lost more weight than females

where divergent selection was implemented.

Selection limit

Selection has been known as a powerful force in chang-
ing the mean expression of the selected trait, but it has been
universally accepted that this power is limited, where selec-
tion may fail to change the mean value of the population any
further. 1

Various theories have been advanced to interpret the
cessation of genetic changes observed by Mather and Harrison
(1949); Lerner and Dempster (1951); Robertson and Reeve (1952);
Falconer and King (1953) and Yamada 35 a1. (1958) in their
long term selection experiments. Briefly, these theories can

be classified into three categories (Lush, 1945; Lerner 1950).

13
1) Exhaustion of genetic variance.
2) Counteracting of natural selection to artificial
selection.
3) Preponderance of non-additive gene action (and
perhaps genotype-environmental interaction).

Differences between a selection limit (ceiling) and
plateau were discussed by Lawrence (1964) from his work with
Drosophila melanogaster. In long term selection studies,
failure of traits to respond to selection for several
generations, followed by an immediate response (Roberts,
19663) for no obvious reason, suggest that plateaus rather
than selection limits might be the most common cause.

Roberts (1966b), working with two divergent lines
(large and small) of mice to determine the limits to artifi-
cial selection for six-week body weight, estimated the
heritabilities of these two divergent lines by reporting an
estimate of .194 and .180 for large and small line, respectiv-
ely. The heritability for large line was not significantly
different from zero while that for the small line was on the
border line of the 5% level of probability to be statistic-
ally significant. He explained these results by stating
that the additive genetic variance in the large line had
been exhausted through the fixation of all alleles affecting
large size, while in the small line a substantial proportion
of residual additive genetic variance was present. Roberts

(1966b) also elaborated on these findings by saying that

l4
selection for small line will reach its limit despite the
fact that the substantial proportion of the additive
genetic variance is present and the loci affecting body
weight in this line had not been fixed by selection.

Irradiating the large line after reaching its
limits for body weight at 6 weeks of age gave a negative
result of introducing new genetic variance while outcross-
ing to an unselected strain and then starting to select
from the cross gave a positive result, but nine generations
were sufficient to recover the original limit (Roberts, 1967b).

Roberts (1966a) reported that despite the fact
that exhaustion of genetic variance and fixation of all
alleles affecting the trait were not obtained, selection
limit may be reached. He ascribed this contingency to
opposition of natural selection to the direction of artificial
selection and to selection favoring those individuals that
are heterozygous at some loci.

Mbnte Carlo technique (simulation genetic systems by
automatic digital computers, where sets of pseudo-random
numbers are employed) was employed in quantitative genetics
by many investigators who studied various genetical parameters
that are involved in inheritance (Cockerham, 1954; Fraser,
1967a, b; Barker, 1958a, b; Fraser, 1960a, b, c; Lewontin
and Dunn, 1960 and Gill, 1965a, b, c). Among the parameters
that have been examined through the Monte Carlo technique by

the above mentioned authors are additive genetic variance,

15
epistatic effect, linkage, genetic drift, selection inten-
sity, inbreeding, gene frequency and environmental variation).
Finite populations were used by Gill (1965a, b, c)

when he examined the relationship of some of these para-
meters to genetic progress through selection. In addition
to that, Robertson (1961) and Gill and Clemmer (1966)
studied the effect of selection on estimation of the degree
of inbreeding coefficient when populations of restricted

size were used.

Heritability

In poultry as in any other livestock animals, most
of the economic traits are quantitative in nature, where
multiple genetic factors are controlling them, which in
turn accounts for their genetical and physiological compli-
city.

The total observed variation in these economic
traits, as well as in the whole population, consists of
genetic variance (02H), environmental variance (02E), and
genetic environmental interactions (ozHE). Thus the total
variance is 02P = 02H + 02E + 02HE. The fraction of the
total actual observed variation associated with a character-
istic which is accounted for by genetic variance is known as
the heritability.

Abplanalp and Kosin (1952) pointed out that herit-

ability may be defined in two ways: 1. In a broad sense, and

16
2. in a much narrower sense. The broader definition is,
"heritability is that fraction of the observed phenotypic
variance which can be ascribed to known genetic differences
between individuals." The narrower definition indicates
that "heritability can be limited to include only the aver-
age gene effects, such as would be expected to appear if

the genes were acting additively.‘ So this means that
heritability in the narrower sense includes in the numerator
variations due to additive gene effects; while in the broad
sense heritability includes in the numerator variations due
to dominance and epistasis besides the additive gene effects.

In terms of variances, Aplanalp and Kosin (1952)

used a formula for heritability in the narrower sense:

 

2
h2 = 08
02g+02d+ozi+02e+02j

The corresponding formula for heritability in the broader

sense is:

h2 = 02g+02d+02i
2.

ozg+ozd+ozi+o2e+o J

 

In the formulas, the symbols represent the following:

2 O O O O
o g = additively genetic var1ance.
02d = variance due to dominance.
2. o o o o o
o 1 = var1ance due to non-l1near genetic interactions

(epistasis).

l7
02e = variance due to environmental effects
ozj a variance due to interaction between genotype and
environment.

Theoretically, heritability can range between 0.0
and 1.0. These two extreme values are rarely encountered
in practice, however. A figure referring to heritability is
descriptive of a specific trait in a particular population at
a given time. If we look at the equation for heritability in
the narrower sense, which is quite useful since it leaves out
genetic effects that probably won't be recovered in later
generations, we see that the formula is in fractional form.
Since it is a fraction, the value of the heritability can be
changed by changes in the additively genetic variance repre-
sented in the numerator or by changes in any one or all of
the components of variance represented in the denominator.

The additively genetic variance is closely associated
with the gene frequency of the gene influencing the trait.
For most situations it is largest when the gene frequency for
the influencing gene is near .5, and this is true where the
alleles at a locus show no dominance.

Knowing the degree of heritability of the traits that
we are interested in is very helpful in achieving the follow-
ing:

1) Devise a sound and efficient breeding program.

2) Predict and estimate the gain to be expected under

mass selection.

l8
3) Construct selection index (see for example,
Hazel (1943)).

4) Determine the accuracy of selection.

5) Predict the expected breeding value.

6) Determine the type of selection to be practiced.

7) Determine type of mating system to be used.

Additive gene action for a trait is important when
the heritability is high, while variations due to additive
gene action are small when heritability is low.

If the heritability of the desired trait is high,
then additive gene action will also be high and mass selection
would be recommended with little real use of progeny test,
pedigree or inbreeding. On the other hand, if the herit-
ability of a trait is low then pedigree, family selection, or

even the progeny test should be considered.

Methods of estimating heritability

 

Different procedures for estimating heritability have
been developed by numerous investigators. Their possible
associated biases were given by Lerner (1950); Lerner (1958);
Falconer (1960a) and Lush (1948). All methods of estimating
heritability rest on the degree to which related animals re-
semble each other more than less closely related animals do
(Lush, 1948 and Kempthorne and Tandon, 1953).

In general, there are two techniques that have been
used to estimate heritability. These techniques are based
on analysis of variance and regression coefficients, though

in certain cases we can cast the analysis in either form.

19

The magnitude of an estimate is influenced by many

factors which lead in some cases to a biased estimation of

heritability, some of these factors are:

1) Absolute amount of genetic variation present

(Moyer 55 a1. 1962).

2)
3)

4)
5)

6)
7)
3)
9)

Environmental differences (Lush, 1940, 1948).
Type of mating system rather than random (Lush,
1940, 1948).

Sampling errors (Lush, 1940, 1948).

Experimental design and method of statistical
analysis (Moyer pp 31. 1962).
Genetic-environmental interaction (Lush, 1948).
Dominance deviation (Lush, 1948).

Epistatic deviation (Lush, 1948).

Initial frequency of genes being selected (Friars

§_t_ §_1.- 1962).

The methods that have been used to estimate the herit-

abilities of various traits observed in animals were given by

Lush (1948). These methods are

1)
2)
3)
4)
5)
6)
7)

Isogenic lines

Regression of offspring on mid-parent
Regression of F3 progenies on F2 individuals
Resemblance of parent and offspring

Intra sire regression of offspring on dam
Selection experiments method

Resemblance between full sibs

20
8) Resemblance between half sibs
9) Resemblance to grandparents
10) More remote relatives
Advantages and disadvantages of most of these methods were
discussed briefly by Lush (1948); Dickerson (1959), Falconer
(1960a) and Turner and Young (1969).

Suggested formulas to estimate the standard errors,
of the heritability coefficients were given by Osborne and
Paterson (1952); Graybill pp a1. (1956); Dickerson (1959);
Henderson (1959); Swiger g£_al. (1964); Nestor 35.31. (1967);
Jensen and Barr (1971) and Becker (1975).

Klein 35 31. (1973) reported a tabulated standard
errors of heritability as estimated by using the following four
different procedures:

1) Regression of offspring on mid parent values

2) Regression of offspring on single parent values

3) Intraclass correlation of full sibs

4) Intraclass correlation of half sibs

These estimates were based on two assumptions:

1) Random mating T

2) Constant number of offspring per family

In addition to the suggested formulas to estimate the
standard errors of the heritability coefficients, confidence
intervals for genetic heritability were also investigated.
Graybill 9; a1. (1956); Graybill and Robertson (1957); Bogyo

and Becker (1963) and Broemeling (1969) reported on confidence

21
limits of heritability where in some cases estimation formulae
have also been suggested.

An excellent reference to many examples was presented
by Becker (1975) in his manual of quantitative genetics in
which estimation of variance components and heritabilities
were given for one way layout, nested, factorial, diallel and
optimal designs. In addition to that he also presented many
examples where regression methods were employed to estimate

heritabilities and their assoCiated standard errors.

Heritability estimates of body weight in chicken

Many investigators have estimated the heritability of
body weight in the chicken. El-Ibiary and Shaffner (l951)report-
ed a series of heritability estimates of New Hampshire's body
weight at consecutive ages by using two methods which employed
variance components analyses. Heritability estimates range
from .00-.57, .05-.38, .03-.38, and .03-.54 for 2, 6, 8 and 10
weeks of age, respectively. Martin gg‘al. (1953), with Rhode
Island Reds, calculated the heritability estimates at 3, 6, 9
and 12 weeks of age. These estimates were .31, .29, .27 and
.31, respectively.

Amer (1965) reported from his work on Fayoumi pullets
that heritability estimates for body weight due to the dam's
contributions were higher than due to the sire's contributions.
On the basis of both the sire's and the dam's contribution,'

he reported that heritability estimates were .36, .54, and .76

22
at hatching, 4 and 8 weeks of age, respectively.

Gaffney (1966) gave an average estimate of the
heritability of body weight at 4 and 8 weeks of age being
equal to about .52 by using the variance components analyses
and intra-sire regression of offspring on dam.methods.

Merritt (1966) reported from his experiment with a
random bred strain of meat type fowl many heritability
estimates ranging from .17 - 1.37 and .24 - 1.14 for body
weight at 7 and 9 weeks of age.

Godfrey and Williams (1952) stated from their selec-
tion experiment with two divergent lines of domestic fowl
where one line was selected for rapid growth and the other
line was selected for slow growth as measured by body weight
at 6 and 12 weeks of age for 2 successive generations that
heritability estimates were .19 and .30 for 6 week body
weight at the first and the second generation, respectively,
while heritability estimates were .31 and .32 for 12 week
body weight for the first and the second generation, respect-
ively. T

Maloney g; 31; (1967) used the intra-sire regression
technique to measure the heritability estimates for six week
body weight which was found to respond to the divergent
selection for 12 week body weight. Their estimates in the
high line were 59 and 57 percent for males and females, res-
pectively, while in the low line, these estimates were 42 and

58 percent for males and females, respectively.

23

Heritability of body weight at 8 weeks of age was
also studied by Dillard gp'gl. (1953); Hurry anleordskog
(1953); Wyatt (1954); Goodman _e_t_ el- (1957); Friars _e_§ _a_l_.
(1962); Siegel (19623, b); Rico (1964); Kinney and
Shoffner (1965); Mahmoud 35,31. (1965); and Carte and Siegel
(1968).

Dillard gppal. (1953) reported a value of .32 for
8 week body weight in a population of New Hampshire pullets
by using the method of intra-sire regression of daughters on
dams. This result is in close agreement to that found by
Hurry and Nordskog (1953) at the same age being equal to .33
and to Rico (1964) who reported a heritability estimate of
.31 for White Plymouth Rock at the same age. The estimates
of Dillard gp‘gl. (1953); Hurry and Nordskog (1953) and Rico
(1964) were also in close agreement with those of Carte and
Siegel (1968) who reported an averaged realized heritability
estimate at the same age being equal to .33 for males and .30
for females. Siegel (l962a) reported a similar result from
his experiment, with White Plymouth Rocks, conducted to inf
vestigate the short term response of individual selection in
two divergent lines for body weight at 8 weeks of age. His
mean realized heritability estimates were .30 and .27 for
males and females, respectively. Similar results were also
obtained by Siegel (l962b) in another experiment,'where he
reported a heritability estimate of .31 and .28 for males and

females, respectively.

24

Higher estimates of heritability were given by Wyatt
(1954) who reported that heritability estimates for body
weight at eight weeks of age were .4 and .46 estimated from
regression of daughters on dam and from full sib correlation,
respectively. Another higher estimate was given by Mahmoud
£3 El. (1965) who calculated the heritability of eight week
body weight of New Hampshires under two environments, as be-
ing .49 t .13 when birds were fed diets with 18 percent pro-
tein and .36 t .22 for those with similar genotypes fed a 24
percent protein ration.

Comparatively, Friars g; 31. (1962) reported higher
heritability estimates computed from the dam component of
variance, which averaged about .87 for both the males and
the females at 8 weeks of age, than what previous investiga-
tors have reported. On the other hand, they also reported
lower heritability estimates computed from the sire component
of variance, which averaged about .13 for both the males and
the females at 8 weeks of age, than what had been previously
known. The differences have been attributed to maternal
effect and heavier selection pressure that had been practiced
on the males which lessened the variance between sire families
and caused the sire components of variance to be less than the
dam components of variance.

Goodman 23 El. (1957) reported various heritability
estimates from their work on the growth rate to eight weeks of

age in two closed flock strains. The heritability estimates

25
for the male progeny ranged from .13 to .68 and .17 to .69
from sire and dam variance components, respectively, while
for the female progeny the heritability estimates ranged
from .00 to .25 and .56 to .81 from sire and dam variance
components, respectively. Heritability estimates of body
weight at 9 weeks of age were investigated by Merritt 33,91.
(1966) who reported realized heritability estimate for body
weight of the chicken at 63 day of age being equal to .49,
while Goodman and Godfrey (1956) reported an estimate of .43
which then was confirmed from another experiment to be equal
to about .5 (Godfrey and Goodman, 1956).

Kruger £5 31. (1952) gave a range for heritability
estimates of 10 week body weight in the domestic fowl being
equal to .33 - .46 calculated from doubling the full sib
correlation and doubling the regression of progeny on dam,
respectively. .

Different estimates of heritability of body weight at
12 weeks of age were given by numerous investigators. In New
Hampshire fryers, Lerner gp_al. (1947) estimated the herit-
ability of body weights by using the analysis of variance
technique. They stated that heritability of body weight at
twelve weeks of age was about .48, .6, and .50 on the basis
of the contribution of sire, dam and both, respectively.
These estimates were higher than the Godfrey and Williams
(1952) and Martin g£_al. (1953) estimates which range between
.31 - .32.

26

Realized heritability estimates for body weight at
12 weeks of age were obtained through the use of the diver-
gent selection program in domestic fowls. Maloney gp‘gl.
(1963b) estimated the realized heritabilities of body weight
at 12 weeks of age as being .34, .07 and .22 for the high
line, low line and the two way selection, respectively.
Maloney and Gilbreath (1966) used a population of Silver
Oklabar chickens for fifteen generations and estimated
higher realized heritability estimates than that which was
reported by Maloney gg'al. (1963b). Their reported realized
heritability estimates, based on combined means of both
sexes, were .45, .17 and .23 for high, low and differences
obtained between lines, respectively. In another divergent
selection experiment, Maloney gp El: (1967) gave an estimate
for the realized heritabilities for these divergent lines as
being equal to 47.2 and 35.1 percent for the males and females
in the high line, respectively, while they were equal to 12.3
and 12.7 percent for males and females in the low selected
line for 12 week body weight. Realized heritability esti-
mates for the difference between the high and low line were
equal to 35.6 and 27.8 percent for males and females, respect-
ively.

Pirchner and Krosigk (1973) used White Leghorns to
estimate heritability of body weight at 18 weeks of age by
employing dam.and sire components of variance techniques.

The average heritability estimates were about .55 and .70

from.sire and dam components, respectively.

27

Hazel and Lamoreux (1947) reported the heritability
of body weight at twenty-two weeks of age as being 31.6
percent. 4

In another series of experiments, body weight herit-
abilities at different ages were determined. Siegel (1963b)
reported mean heritability estimates for body weight at 4,

24 and 38 weeks of age as being equal to .53, .46 and .38

for females, while for males at 4 weeks of age it was .53.
These estimates are in agreement with those estimates reported
by Siegel (1963a) of .47, .44 and .43 for 4, 24 and 38 week
body weights, respectively.

King (1961) estimated the heritability of body weight
at 32 weeks of age as being .62. Festing and Nordskog (1967)
reported from their 2-way selection experiment for body
weight at 32 weeks of age in chickens asymmetrical heritability
estimates where the heritability for upward and downward
selection was .34 and .52, respectively.

Ideta and Siegel (1966a) reported from their study
on the realized heritabilities of unselected traits (24 and
38 week body weights) when 2-way selection (one upward and
one downward) was employed for body weight at eight weeks of
age, that realized heritabilities based on the regression of
divergence on the expected secondary selection differential
for unselected traits was .44 and .54 for body weight at 24

and 38 weeks of age, respectively.

28

Estimate for mature pullet body weight heritability
was given by Goodman and Godfrey (1956) as .57, while Yamada
(1958), using closed flocks of Single Comb White Leghorns,
Barred Plymouth Rocks and Rhode Island Reds for a period of
about four years, gave a lower estimate of heritability, be-
ing .46 for body weight at 300 days based on combined sire
and dam components. Shoffner and Sloan (1948) reported much
higher heritability estimate of adult body weight taken at
approximately 300 days of age, being .75 calculated by the
method of intra-class correlation.

Many investigators have reported on the heritability
of broiler's body weight at different ages. Peeler g; 31.
(1955) found that heritability estimates for broiler weight
range from .15 to .38 by employing the analysis of variance
and intra-sire regression of offspring on dam techniques.
Moyer gp'gl. (1962) estimated heritability of body weight at
4, 6 and 8 weeks of age in cross-bred broiler chickens by
using components of variance model. Sire component herit-
ability estimates averaged for the males at 4 and 8 weeks of
age .20 and .24, respectively, while for the females they
averaged .26 and .35, respectively. Using dam variance compo-
nents led to higher estimates in comparison to those from the
sire components. On the other hand, heritability estimates
calculated by Godfrey and Goodman (1955) on their selection
experiment for small and large body size in broiler chickens

averaged about 26 percent for six and twelve week body weights.

29

Dev pp 51. (1969) reported from.their work on the
genetics of eight week body weight in three broiler popula-
tions of chickens an averaged estimate of .25 for the real-
ized heritability of eight week body weight. Higher herit-
ability estimates of 59 day live weight in broilers were
given by Siegel and Essary (1952) who reported a range of
.26 - .76 with an average of .49 by employing half sib and
full sib correlation techniques.

Heritability estimates of 10 week body weight in
broilers were studied by Lankford and McClung (1952) who
reported a range of .2 to .63 by using analysis of variance
technique, while Brunson gp‘al. (1955) reported that herit-
ability of 10 week body weight in broilers was equal to .45
which falls in Lankford and McClung's (1952) range.

Glazener e5 §l° (1951) reported from their work on
the effect of inbreeding on broiler weights and feathering
in the fowl a range of 51-79 percent as an estimate for
twelve week body weight heritability in the fowl.

A range of .71 to .85 was reported by Peeler pp a1.
(1955) for the heritability of body weight at sexual matur-
ity in broilers which was derived from the analysis of vari-
ance and intra-sire regression of offspring on dam.techniques.

A compiled estimate of heritabilities from.many pre-
vious experiments for a number of traits in domestic fowl
which was given by Kinney (1969) will be of great help for

those seeking information about the genetic architecture of

30
body weight at different ages and other reproductive traits
in poultry. Also another excellent review which will be of
great help to many people was given by Siegel (1962a) where
a summary of 176 published heritability estimates of body
weights obtained at ages ranging from 6 to 12 weeks was shown

in a histogram.

Heritability estimates of body weight in turkey

During recent years a considerable amount of investi-
gational research has been carried on to study the criteria
of genetic parameters of body weight in turkeys. Abplanalp
and Kosin (1952); Bumgardner and Shaffner (1954); Goodman
§§_§l. (1954); Kondora and Shoffner (1955); McCartney (1955);
Johnson and Asmundson (1957a, b); McCartney (1961) and Krueger
22.31. (1972) reported that body weight is a highly heritable
trait in the turkey.

Jaap (1938); Asmundson and Lerner (1940); Asmundson
(1944, 1945, 1948) and Asmundson and Pun (1954a, b) reported
from their investigational works with turkeys that body size,
growth rate and conformation traits are influenced by genetic
variation.

Heritability of body weight at different time inter-
vals was examined by numerous scientists. Bumgardner and
Shaffner (1954) reported on the heritability of body weight
of medium-sized white turkeys at 2, 4, 8, 16 and 24 weeks of

age by employing the analysis of variance technique. Their

31
estimates varied from 2 percent at 4 weeks of age to 46
percent at 16 weeks of age for males. For the females,
these values ranged from 3 percent at 4 weeks of age to 32
percent at eight weeks of age.

Abplanalp and Kosin (1952) used intra class correla-
tion and offspring dam regression methods to estimate the
heritability of body weight at 4, 8, l4 and 26 weeks of age
for Broad Breasted Bronze and Beltsville small white turkeys.
The highest estimates at 14 weeks of age for Bronze males
was 71 percent and 39 percent for Bronze females. The high-
est estimate at 8 weeks of age for Beltsville small white
male turkeys was 33 percent, for the females it was 24 per-
cent at 26 weeks of age. Krueger g3 gl.(l972) studied the
heritability of body weight and conformation traits and their
genetic association in turkeys. They used Broad Breasted
Bronze turkeys and estimated the heritability of body weight
at 8 and 14 weeks of age by using full sib correlations
method. They found that the heritability of body weight
varied from .31 to .41 using male progeny and .20 to .39
using female progeny.

Heritability of body weight at 8, l6 and 24 weeks of
age was studied by Johnson and Asmundson (1957a) who gave a
range of .5 to .6 for the heritabilities at these three ages,
while a wider range of .28 to .65 was reported by Nestor 35 gl.
(1967) for the heritabilities at the above mentioned three

ages. McCartney (1961) calculated heritability estimates on

32
random.bred control population of turkeys at 8, 16 and 24
weeks of age. The heritability estimate based on full sib
correlation averaged approximately .6 for body weight at
these three ages.

In another study, McCartney gp‘gl. (1968) reported
that realized heritability estimates for 8 and 24 week body
weights averaged .44 and .39, respectively.

Heritabilities of body weight at 12 weeks of age were
calculated by Mukherjee and Friars (1970) who reported that
they range from medium to high while Johnson and Gowe (1962)
estimated them to be .35 and .36 for males and females, res-
pectively.

From the same experiment, Johnson and Gowe (1962)
reported that heritability of 24 week body weight was .4 and
.48 for males and females, respectively. These results were
confirmed by Cook £5 a1. (1962) who gave an average estimate
of the heritability at 24 weeks of age after employing sire
and dam variance component methods as being .45. Kondra and
Shoffner (1955) estimated the heritability of body weight at
24 weeks of age using the method of intra-sire regression of
offspring on dam. Their heritability estimates ranged from
.24 to 1.12. McCartney (1955) used White Holland turkeys in
order to study the heritability and genetic, phenotypic and
environmental correlations of body weight at 16 and 24 weeks
of age. The estimates of the heritability based on half sib

correlations were .23 and .33 for males at 16 and 24 weeks

33
of age, respectively. Heritability estimates for the
females were .59 and .61 at 16 and 24 weeks of age, respect—
ively.

Analysis of variance technique was employed by
Goodman £5 a1. (1954) for the purpose of estimating the
heritability of 25-week body weights of Broad Breasted Bronze
and White Holland turkeys, which was found to average about
.30. Based on that, they recommended a combination of mass
and family selection for the most efficient improvement in
body weight.

A lower estimate than what was reported by Goodman
gg‘gl. (1954) was obtained by Kentucky workers (1950) who got
an estimate of 23 percent for 26-week old small type white

male turkeys where intra-sire regression method was employed.

Heritability estimates of body weight in other species of
pouItry

Research dealing with the area of estimating the herit-
ability of body weight in other species is meager, and to the
author's knowledge, heritability estimates for body weight in
Ring-Necked pheasants has not ever been reported.

A review of the literature revealed a limited amount
of work that has been done to estimate the heritability of
body weight in Japanese Quail. Sefton and Siegel (1974) gave
many heritability estimate ranges for body weights at differ-
ent ages. These ranges were .03 to 1.42, .12 to .37, .11 to
.68, -.03 to 1.18, .28 to .79, .49 to .65, .51 to .72, .39 to

34

.65 and .49 to .76 for males at l, 7, 14, 21, 28, 35, 42,
49 and 56 days, respectively. For the females the ranges
were -.05 to 1.82, .25 to .56, .25 to .48, .12 to .70, .17
to .65, -.43 to .68, -.21 to 1.48, .25 to .46 and .34 to
.46 for the above same ages, respectively. Marks and Lepore
(1968) reported that the average heritability estimates at
14 days of age were.12 - .60 and .21 - .56 for males and
females, respectively.

Estimates of the heritability of body weight at four
weeks of age in Coturnix by Yoshida and Collins (1967);
Marks and Lepore (1968) and Marks (1971) ranged from .22 to
.76 in males and .27 to .76 in females, which are in close
agreement with Sefton and Siegel's (1974) estimates.

Parshotam and Johnson (1974) reported on their study
of the intra-sire regression of offspring on dam as a measure
of the additive genetic variance for five week body weight in
Coturnix coturnix Japonica. Heritability estimate was .43
based on the regression of daughter's weight on dam's weight.
They also stated that heritability estimate was .24 based on
regression of son's weight on dam's weight, where the ratio
of the standard deviation of female weight on the standard
deviation of male weight served as a correction factor to
adjust for sex differences.

Sittman 25 a1. (1966) and Collins g5 El. (1970)
reported estimates of the heritability of body weight at six

weeks of age (near sexual maturity), ranging from .38 - .72

35
and from .06 to .25, respectively, while Collins and
Abplanalp (1965) gave an estimate for the realized herit-
ability for 6 week body weight in Japanese quail of .14.

Strong pp 31. (1978) reported from their study on
the inheritance of body weight at sexual maturity in Coturnix
by using paternal half-sister correlation and maternal half
sister correlation that heritability estimate was found to
be less than .2 and greater than 1.0, while Kawahara and
Inoue (1966) and Kawahara and Kusaka (1970) found it to be
.42 and .31, respectively.

Estimated heritabilities of body weight at ages
further removed from sexual maturity were given by Rodero
and Martinez de Minguel (1963); Marks and Kinney (1964) and
Kawahara and Saito (1976), who reported medium to high esti-

mates .

Genetic and phenotypic correlation

 

The concept of correlation, which is widely used by
researchers, resulted primarily from the works of Galton and
Pearson near the turn of the century. Gill (1974) stated
that "correlation is a measure of the degree of association
or interdependence of two variables". Correlation estimates
range from .00 to 1.00. .00 means that there is no correla-
tion, while 1.00 means there is perfect correlation. Perfect
correlation is not found in many biological systems. By

using correlation we can tell how accurate our predictions are.

36

Genetic correlation, which should not be confused
with phenotypic correlation, is a correlation that exists
between breeding values of two traits in the same individual,
while the phenotypic correlation is a combination outcome of
genetic and environmental correlations. Since the relation-
ship between the additive effects of two traits is measured
by the genetic correlation, then covariance between these
additive effects will be used to estimate the genetic corre-
lation (Peeler £5 El. 1955).

The genetic correlation can be caused either by link-
age or pleiotropy where linkage effect is transient, while
pleiotropic effect is more permanent (Falconer and King,

1953; Bohren g; 31. 1966 and Cheung and Parker, 1974).

Standard errors of genetic correlation have been in-
vestigated by Robertson (1959) and Tallis (1959), who suggest-
ed statistical formulae to estimate standard errors of genetic
correlation, while many tabulated standard errors for genetic
correlation were given by Klein £5 a1. (1973).

Artificial selection experiments for the improvement
of a particular trait have frequently resulted in associated
changes of other unselected characteristics. These associated
changes are termed correlated responses. Theoretical aspects
of correlated responses and estimation procedures of genetic,
phenotypic and environmental correlations have been reviewed

by Lerner (1958) and Falconer (1960a).

37

A considerable number of selection experiments have
been conducted in order to study direct and correlated res-
ponses to selection. Among the publications are those of
Hazel (1943); Hazel gg‘al. (1943); Lerner (1950); Reeve and
Robertson (1953); Falconer (1954); Clayton g5 El. (1957);
Robertson (1959); Martin and Bell (1960); VanVleck and
Henderson (1961); Maloney and Gilbreath (1962); Nordskog and
Festing (1962); Siegel (1962a, b); Maloney et al. (1963b);
Siegel (1963b); and Bohren £5 a1. (1966).

Correlated responses have also been investigated by
Falconer (1960b), Bell and McNary (1963) and Yamada and Bell
(1963) under two different environments, where asymmetrical
correlated responses have been observed.

There are three types of correlated responses which
occur between a selected trait and un unselected trait.
Falconer (1954) discussed these three types of correlated res-
ponses. These three types are:

1) If two traits are genetically correlated, then
selection for the primary trait will cause direct
change in the secondary trait. For example, see
Lerner (1946) and Falconer (1954).

2) If two traits are genetically uncorrelated, then
no correlated response would be expected, but the
secondary trait may nevertheless show an undirected
departure from the original population, following

selection for the primary trait. For example, see

38
Mather and Harrison (1949).

3) If the secondary trait forms an important part
of the total fitness, then selection for the
primary trait in either direction might result
in secondary trait decline. This type of res-
ponse has been termed "genetic homostasis" by
Lerner (1950, 1954). For example, see Nordskog
and Festing (1962).

Hutt (1949) indicated that body weight at hatching
dependsmore upon the weight of the egg from.which that chick
hatches than upon anything else. Upp (1928), Halbersleben
and Mussehl (1922) and Wiley (1950) found that egg weight and
day old chick weight are highly correlated. Upp (1928)
estimated the positive coefficient of correlation between
egg weight and chick weight at hatching time to be equal to
.68 - .84. Hutt (1949) reported that under normal conditions
chick weight at hatching time represents 61-68 percent of the
egg from which it hatched, while Halbersleben and Mussehl
(1922) observed that chick weight at hatching recovers sixty-
four percent of the egg weight.

Gaffney (1966) found that four week body weight is
affected by egg size, especially in the female progeny, while
at eight weeks of age, male's weight was negligibly affected,
and the magnitude of effect in females weight was almost half
that at four weeks. On the other hand, Halbersleben and

Mussehl (1922) reported that at thirty-five days of age all

39
chicks hatched from small and large eggs will average
approximately the same weight.

These results were not in agreement with those
reported by Wiley (1950) who reported further that any dis-
advantages newly hatched chicks acquired from the small eggs
were overcome by the twelfth week of age. In addition to
the findings of Halbersleben and Mussehl (1922) and Wiley
(1950), Upp (1928) examined the relationship of chick weight
at hatching and the subsequent growth rate at various ages
and found that chick weight at hatching is not a reliable
index for two, four and twelve week weights. Upp's results
were confirmed by Funk (1930) who observed no significant
correlation between day old weight and weight at 4, 8, 12,
16, 20 and 24 weeks of age.

Since Hazel (1943) reported a method for estimating
the genetic correlations, numerous reports have been published
concerning the genetic relationship between various economic
traits in poultry. Estimate of the degree of genetic rela-
tionship is subjected to biases in the same manner as herit-
ability estimates. The biases reflect large sampling error,
which results in a wide range of estimates.

McCartney (1955) observed a positive genetic correla-
tion of about .92 between body weight at 16 and 24 weeks of
age of White Holland turkeys. Johnson and Asmundson (1957a),
in a strain of Bronze turkeys, observed that genetic correla-

tions between body weights at 8 and 16, 8 and 24 and 16 and

40

24 weeks of age averaged .86, .83 and .99, respectively.
McCartney (1961) obtained corresponding estimates of .49,
.71 and .90. In another study, McCartney 3E El- (1968)
estimated an average realized genetic correlation in White
turkeys between body weights at 8 and 16, 8 and 24 and 16
and 24 weeks of age as being 1.08, .73 and .98, respectively.
Nestor 33 El. (1967) reported from their work with random
bred control turkeys that genetic correlation estimates among
body weights at 8, l6 and 24 weeks of age were large (above
.55) and positive. Johnson and Gowe (1962) estimated the
mean genetic and phenotypic correlations between 12 week and
24 week body weights of domestic turkey males as being equal
to .64 and .61, respectively, while for the females they were
equal to about .8 and .67, respectively. Funk (1930) reported
from his work on the rate of growth in Bronze and White
Holland turkeys a similar result to that reported by Bumgardner
and Shaffner (1954) by showing that as age increased, the
correlations of weights at younger ages with 24 week body
weight will increase. Bumgardner and Shaffner (1954) have
shown that these correlation coefficient values reached .71
for males and .52 for females between 16 and 24 week weights.

Genetic correlation of .75 in some broiler type popu-
lations of chicken were reported for eight week body weight

between the two sexes by Comstock (1956).

41

In two divergent growth selected lines, Maloney
gg‘gl. (1963c) reported highly significant correlations be-
tween 6 and 12 week body weights. These correlations were
equal to .25 and .53 in the high and low lines, respectively.
On the other hand, Ideta and Siegel (1966b) reported from
their study on White Plymouth Rocks, where two divergent
growth selected lines had also been established, that mean
realized genetic correlations between 8 week body weight and
post juvenile (24 and 38 weeks) weights were equal to .62
and .52 for 24 and 38 weeks of age, respectively.

An excellent review with numerous reported estimates
of genetic and phenotypic correlation was given by Kinney
(1969). This information will be of great help to those
seeking information regarding the subject of genetic, pheno-
typic and environmental correlation.

A clear understanding of the heritability and the
genetic correlation of the trait we are studying is vitally
important to the effectiveness of selective breeding programs.
We need reliable and accurate estimates of heritability and
genetic, environmental and phenotypic correlations so that we
have efficient selection which will result in achieving

maximum improvement in total productivity.

MATERIAL AND METHODS

A three year experiment (1974-1977) to study the
genetic parameters of body weight in Ring-Necked pheasants
was conducted at the Department of Poultry Science Research
and Teaching Center, Michigan State University.

The base population was obtained on October 1, 1974
from the Michigan Department of Natural Resources Game Farm,
Mason, Michigan. It was composed of four hundred and eighty
one-day old chicks.

All pheasant chicks were wing banded, individually
weighed at one day old, and then housed in brooding facilities
at the Michigan State University Poultry Science Research
and Teaching Center (P.S.R.T.C.).

The brooding facilities consisted of twelve floor pens
(3.05 x 4.88 m), which had been thoroughly cleaned and dis-
infected.

The pens were separated from each other by wire netting
partitions. Each pen housed forty straight-run chicks.

Heat was provided by infra-red heat bulb lamps, and
gas heated hover type brooders. .For the first week, corrugated
chick guards were used to form a circle (about 120 cm in
diameter) around the heat source; the purpose of the circle

was to confine the chicks to this area. Heat lamps and gas

42

43
heated brooders were added or removed as necessary in
order to regulate the temperature inside the house.

Attempts were also made to provide the maximum
amount of ventilation in keeping with the comfort of the
chicks and the weather conditions. When the pheasant chicks
were four weeks of age all heat lamps were removed, and all
birds were individually weighed.

A pheasant starter ration (Appendix Table l) and
water were provided ad_1ibitum. For the first two weeks of
the experimental period flat type feeders and jar-waterers
were employed, and these were then replaced by hanging
feeders and automatic waterers. Water in the water founts
was kept at a certain level to prevent dampness of the shav-
ings litter beneath the founts.

At six weeks of age, pheasant chicks were switched
from pheasant starter to pheasant grower ration (Appendix
Table 3).

At eight weeks of age, pheasant chicks were indivi-
dually weighed and specked through the use of specks in
order to control the cannibalism problem. Specks were fitted
over the beak with plastic pin attached through the nostril,
so the bird could see to both sides, up and down but not
straight ahead.

At twelve weeks of age, all birds were individually
weighed and sex was determined by the use of the plumage color.

Mass selection (which is a method of selection that

is based on individual body weights) was employed at lZ-weeks

44
of age in a divergent selection program.where two lines
were separated from.the base population, one selected for
heavier body weights and the other for light body weights,
the criterion of selection being weight at 12 weeks of age.
The line selected for heavier body weights consisted of all
the selected males that had body weights of 1150 grams or
above and the selected females that had body weights of 825
grams and above. The line selected for light body weights
consisted of all the selected males that had body weights of
800 grams or below and the selected females that had body
weights of 700 grams or below.

Forty-five females (25 light and 20 heavy) and nine-
teen males (9 light and 11 heavy) were saved to produce next
generation progenies. The ranges of lZ-week body weight of
these birds were 510-700, 675-800, 825-940 and 1150-1210
grams for light females, light males, heavy females and heavy
males, respectively, while their 12-week body weight means
were 656, 764, 863 and 1163 grams, respectively.

The selected birds were then transferred to differ-
ent pens, while the culled birds were saved for an additional
weighing which was scheduled to be taken on February 4, 1975,
when all birds were eighteen weeks old. When the birds were
thirteen weeks of age, the ration was switched from pheasant
grower to pheasant flight (Appendix Table 5), and the birds
were then raised in complete darkness to minimize cannibalism.
All birds were raised on pheasant flight until time of light-

ing.

45

At eighteen weeks of age, all birds were again in-
dividually weighed, then all the culled birds which had
been saved for eighteen week weighings were sent back to
Mason, Michigan to be used in the put-take program which
was initiated in Michigan in 1972 to provide pheasant huntu
ing recreation on state-owned lands.

On June 16, 1975, all the selected birds, which were
about 37 weeks of age, were removed from darkened pens and
housed in individual cages, mounted in battery frames.

The birds at the time of caging received 14 hours
of light (6 a.m. to 8 p.m.) per day as provided by 60 watt
frosted incandescent light bulbs. At the same time all birds
were switched from pheasant flight to pheasant breeder ration
(Appendix Table 7).

At the conclusion of a two week pre-lighting period,
the birds were moved from the battery and housed in indivi-
dual wire cages which measured 7x14x12 inches (.18 x .36 x
.31 m) and were mounted on the wall within four single male
mating pens, each of which measured 10 x 16 feet (3.05 x 4.88 m).
Sixteen hours of light per day (6 a.m. to 10 p.m.) was pro-
vided by one 60 watt frosted incandescent light bulb per
breeding pen .

Twenty-eight females (17 light + 11 heavy) and four
breeding males (2 light + 2 heavy) were used to produce next
generation progenies. Heavy males were mated to heavy females

and light males were mated to light females in order to develop

46
two divergent lines of Ring—Necked.pheasant, where one line
was selected for heavier body weight and the other line was
selected for lighter body weight.

The ranges of lZ-week body weight of these birds
were 510-685, 675-750, 850-940 and 1170-1210 grams for light
females, light males, heavy females and heavy males, respect-
ively, while their 12-week body weight means were 639, 713,
886 and 1190 grams, respectively.

Eight light females were mated with one light male
in the first pen, while nine light females were mated with
the second light male in the second pen. In the third pen
five heavy females were mated with one heavy male, while six
heavy females were mated with the second heavy male in the
fourth pen. Stud mating system was employed where two pullets
were drOpped in a 10 x 16 foot (3.05 x 4.88 m) single male
mating pen in the morning and returned to their cages in the
afternoon. Stud mating system allows all females to be
rotated so that each pullet will be available for natural
mating at least once each week. After the matings were made,
seven days were allowed to assure good fertility before pedi-
greed egg production was recorded.

Individual egg production records were maintained on
all females selected as parental stock, where daily indivi-
dual egg production was recorded between July 5, 1975 and
October 31, 1975 and then hen housed and hen day egg produc-

tions were calculated. All pedigreed eggs, which were

47
collected daily, were held at 60 degrees Fahrenheit in
order to cut down on the embryonic development during the
holding stage. During the breeding season, pedigreed eggs
were set at l4-day intervals in Jamesway 252 incubators to
allow for the maximum number of chicks per hatch and a good
hatchability. All eggs were brought to room temperature
before being placed in the incubator.

The eggs were incubated for three weeks at 99.50F
(37.30C) and 60% relative humidity. After twenty-one days
of incubation, the eggs were transferred to hatching units
operated at 98.50F (36.10C) and 70% relative humidity for
three days. At time of transfer to the hatcher, eggs were
placed in wire pedigree baskets according to dam number to
make it possible to pedigree the chicks.

On the day of hatching, percent hatchability was cal-
culated, and all birds were individually weighed, wing banded
and pedigreed by sires and dams. Chicks were then trans-
ferred to the P.S.R.T.C. for brooding. A total of five
hundred and seventy-three birds were hatched in the first
generation.

Gathering eggs from the previous pullet breeders was
continued for six weeks after the removal of the males from
the mating pens. These eggs were also set in the incubator
in order to study the duration of fertility.

Mortality was recorded as it occurred and dead birds

were removed from the pens and sent to the veterinary

48
diagnostic laboratories, Department of Pathology, M.S.U.
to determine the cause of death. Mortality calculation was
expressed as a percent of the total birds died to the total
chicks housed for each generation separately.

The first generation chicks were exposed to the same
breeding and management procedures which were practiced in
the base population. Attempts were also made to give the
same environmental conditions in order to minimize any
effect that could result from any fluctuating in these
environmental factors. All chicks which were hatched in the
first generation came from eight different hatches, where
eight breeding pens were used in 1975 to accommodate them.
Both of the growth—selected lines from each hatch were brooded
together in the same pen in order to minimize the environment-
al effect. All birds within each hatch were individually
weighed at 4, 8, 12 and 18 weeks of age.

The same feeding program as for the base population,
where pheasant starter (Appendix Table l), pheasant grower
(Appendix Table 3), pheasant flight (Appendix Table 5) and
pheasant breeder (Appendix Table 7) were used from 0-6 weeks
of age, 6-13 weeks of age, 13 weeks of age until time of
lighting, and after time of lighting, respectively, was used
for the first generation birds. Pheasant starter, grower,
flight and breeder rations were adequate in all known nutri-
ents based on calculated analysis (Appendices Tables 2, 4, 6,

8).

49

At twelve weeks of age, mass selection was used and
the same specific standards that were used on the base popu-
lation were employed. None of the heavy males or the heavy
females that were saved to produce the selected heavy line
for the next generation came from light male and light female
crossing. The same thing stands true for light males and
light females, where none of them came from heavy male and
heavy female crossing.

Fifty-seven females (27 light and 30 heavy) and
twenty-three males (6 light and 17 heavy) were saved to pro-
duce next generation progenies. The ranges of 12-week body
weight of these birds were 516-700, 591-791, 825-978 and 1186-
1387 grams for light females, light males, heavy females and
heavy males, respectively, while their 12-week body weight
means were 646, 746, 879 and 1246 grams, respectively.

All the selected birds were again raised in complete
darkness until time of lighting. On June 4, 1976 all the
selected birds were removed from darkened pens and housed in
the same individual cages mounted in battery frames which
were used the previous year. At time of caging all birds
received 16 hours of light (6 a.m. to 10 p.m.) per day as
provided by 60 watt frosted incandescent light bulbs. The
same individual wire cages that are mounted on the wall within
four single male mating pens that were used the previous year,
were used again in the second year. Thirty-one females (15

light + 16 heavy) and four breeding males (2 light + 2 heavy)

50
were used in the breeding system.

The ranges of 12-week body weight of these birds
were 516-678, 591—735, 847-978 and 1265-1387 grams for
light females, light males, heavy females and heavy males,
respectively, while their 12-week body weight means were
627, 663, 910 and 1326 grams, respectively.

Divergent mating, where heavy males were mated to
heavy females and light males were mated to light females,
was again employed.

Nine light females were mated with one light male in
the first pen, while six light females were mated with the
second light male in the second pen. In the third pen ten
heavy females were mated with one heavy male, while six heavy
females were mated to the second heavy male in the last pen.
Stud mating system was also employed so that each pullet was
rotated for natural mating at least once each week. The
rate of inbreeding in the population was kept to a minimum
by deliberately avoiding matings of close relatives.

Daily individual egg production was recorded between
June 26, 1976, and September 3, 1976, and hen housed and hen
day egg productions were calculated.

The same system of holding and incubation conditions
that was used the previous year was again used. A total of
6 hatches (four hundred and five baby chicks) were made in
the second generation.

In addition to that, a total of three hundred and

ninety eggs from the Michigan Department of Natural Resources

51
Game Farm, Mason, Michigan were set in the incubator to
secure chicks to be used as a control.

At hatching time, percent hatchability was calculated,
and all birds that were hatched were wing banded and indivi-
dually weighed at one day of age. The chicks were then trans-
ferred to the P.S.R.T.C. for brooding.

Two hundred and nineteen baby chicks were hatched
from.two different control hatches. These chicks represent a
control group that came from a random population, where no
selection and/or preferred mating system had been applied for
many generations.

This control group was to be used to make a compari-
son between the two divergent lines that were subjected to
upward and downward type of selection, and to determine how
well these two lines were responding to these kinds of selec-
tion.

The two control hatches were hatched at the same time
as the second and third selected hatches were hatched, so
chicks that came from the first control group were raised in
the same pen with the chicks that came from the second
selected hatch. The second control hatch of chicks were
raised in the same pen with the third selected hatch chicks.

Eight brooding pens were used in 1976 to accommodate
the six selected hatches and the two control hatches. Chicks
from each hatch were again put in the same pen, no matter

what type of selection was practiced on them.

52

The second generation chicks were also exposed to
the same brooding and management practices that were used
in the base and the first generation. All possible attempts
were made to furnish the same environmental conditions that
the chicks had been exposed to in the previous two genera-
tions.

The same feeding program used in the previous two
generations was used up to eighteen weeks of age. All birds
within each hatch were individually weighed at 4, 8, 12 and
18 weeks of age.

All birds, after twelve week weighings, were raised
in darkness until eighteen weeks old, at which time they
were released.

On March 2, 1977, the experiment was terminated and

all data were subjected to statistical analysis.

RESULTS AND DISCUSSION

The analysis of the data was confined to the birds
which lived until the end of 18 weeks weighing period from
each generation and gave a complete record with respect to
the required data.

The application of the regression techniques was
considered in part of the statistical analysis, where
parent's record was repeated for each progeny. Repeating
parent's records was found to be more efficient than taking
progeny means (Bohren $3.31. 1961). Regression computations
in this study were done on CYBER 170 Computer at Michigan

State University.

Effect of selection

 

Individual selection for heavy and light body weight
at 12-weeks of age has been practiced for two generations in
Ring-Necked Pheasant population.

The mean body weights for each sex at the five suc-
cessive ages for all generations are given in Tables 1 and 2.
These tables show that selection has resulted in mean body
weight differences of about 2, 49, 168, 283 and 381 gm in
the males and 2, 54, 156, 264 and 327 gm in the females at

one-day, 4-weeks, 8-weeks, 12-weeks and 18-weeks of age,

53

54

 

 

 

 

on.Hmm ~w.mmma mm.¢~m Hm.anHH oo.oom No.¢naa oo.amm mm.a¢ma mxoozuma
nm.¢~n No.0Hm om.oao Hm.o~w mo.mmm mw.omm nw.m¢m Nw.mmm mxoozuma
nm.om¢ om.mmm mo.HH¢ mm.¢m¢ o~.mm¢ Hm.mem Hq.mw¢ Hm.mmm axoosnm
No.NH~ oo.mm~ Hm.~ma N¢.HwH em.oqa mo.~na nn.nma Hm.NNN axooBuq.
m¢.H~ mo.HN Nu.mH NH.mH mH.mH Nu.aa Ho.om om.o~ oao
amonoco

owun owns mans menu moan: moans «owns «mans

moawaom moamz moamaom moamz monEom moan: moamaom moamz

nnma nmma omaa mnma

Houunoo aowumuocow oaooom aowumuoaow umhflh aowumuocom ommm ow¢

.muammmosm ooxooZuwawm mo mafia oouooaom uswfia osu

mo sowumasmom Houucoo moo one coaumhocow ocooom one umuwm .omon now own mo
mXoozlmH one mxooSuNH .mxooBuw .mxoo3u¢ .hmouoao um Aamv muswfio3 moon and: .H mqm<H

55

 

 

 

 

on.amm mm.mmma Ho.HmHH wm.a¢ma ma.mnoa Hm.o¢¢H mo.amm m~.H¢mH mxooBuwH
mm.¢~n No.0Hm mn.owm mm.moaa Hm.o¢m wo.oaaa nw.m¢m Nw.~mm mxoo3uma
mm.om¢ om.mwm “a.mem No.moo N¢.mom mw.omo H¢.mm¢ Hm.mmm mxoo3um
No.NHN oo.mm~ mm.HHN Hm.omm qm.ona mm.¢ma mn.mma Hm.NNN mxoozue
n¢.HN no.Hm mm.om «m.om Hm.om NH.HN Ho.om om.o~ oHo
moonoco

own: owns on“: mmua mm": Nona «owns Nwana

moamaom moan: moHMEom monz moamaom moamz moamaom moamz

mnma nnma omma mmmH

Houunou cowumuoaow oaooom GowumHoSow umuwh cowumuocow ommm ow<

.mucmmmonm ooxooZuwch mo mafia oouooaow h>mon can mo

aowumHomom Houunoo onu one nowumuocow ocooom onm umuwm .ommn now own mo
axooanwa ocm axooslma .mxoozum .mx003ue .hmouoco um Aawv munwwoa hoop coo: .N mAm<H

56

respectively, between the two diverse selected lines. In

addition to that the effectiveness of the two-way selection

was so pronounced that second generation females in the

heavy body weight selected line were about 1, 30, 73 and 54

gm heavier than males in the light body weight selected line

at one-day, 4-weeks, 8-weeks, and 12-weeks of age, respectiv-

ely, while they were about even in weight at 18-weeks of age.
The response in one-day, 4-weeks, 8-weeks, 12-weeks,

and 18-weeks old body weights to the divergent selection pro-

gram where the criterion of selection being weight at 12-

weeks of age over a period of 2 generations are shown in

Figures 1, 2, 3, 4 and 5. The points utilized in these figures

are the generation's body weight means at the above specific

ages as exhibited by respective sexes. The results show the

effectiveness of the divergent selection program in increas-

ing and decreasing body weight at these ages in both sexes.
The following conclusions can be drawn from an inspec-

tion of Tables 1 and 2 and Figures 1, 2, 3, 4 and 5.

1) There is no doubt about the efficacy of selection both in
increasing and decreasing weight.

2) Selection response as exhibited by the divergence between
the two selected lines shows a considerable amount of
change in two-way directions.\

3) In general the heavy selected line gained more weight by
plus selection than was lost from the light selected line

by minus selection.

57
4) In general males gained or lost more weight than females.
5) Progress in both selected lines appears erratic. This
irregularity is similar to that reported in other selec-
tion experiments.

Falconer (1953a) suggested possible causes of an
asymmetrical response to two-way selection. These causes are:

l) Unequal gene frequencies: where the frequency of
genes acting in one direction being higher than those acting
in the other direction. Bohren £2,21- (1966) stated that
"probably the most frequent contribution to asymmetry in
practice will be from loci contributing negatively to the
covariance and having frequencies other than .5."

2) Directional dominance: where more numerous loci
having the dominant allele act in one direction than those that
have the dominant allele and act in other direction. In addi-
tion to that, directional dominance causes inbreeding depres-
sion which in turn results in an asymmetrical response to
selection.

3) Unsuitable metric: when scale of measurement used
makes the genes action multiplicative instead of additive.

Falconer (1953a) referred to Mather (1949) by saying
that removing directional dominance due to unsuitable scale
can be obtained by transforming weight measurement to a suit-
able scale. It should be noted that MacArthur (1944a) and
Falconer (1953a) agree that logarithmic scale meets the condi-

tions of being a suitable scale.

One-day body weight (gm)

22

21

20

19

 

58

 

o:
*****oo******" "****tt.*,*. Heavyline
* .0. ....0. ‘
.ffi. '0. Heavy line
0'. ”a Female
0' at
0 fl
'0. W
.0... fig.
0"... # # #
...‘0 * ‘fl’
.'0. It # *.
.O. * o o
’0.... a # Light line
000000....... # Male
ooooooog... Light line
Female
0 1 2
Generation

Figure l. The effect of selection for lZ—week body weight
on one day body weight

4-week body weight (gm)

59

 

 

250
1 Heavy line
a 1‘ Male
:6
t 1*
‘*;4". ,*‘
I; *4)? 1* . Heavy line
# a 1* 0' Female
’3 *4 c '
§ * * a .0.
200 ## i * ¥ E 0..
o. - t +1 .0
0... fl * .
O. .... * ...
. '0 o
0.. .....fi# ....
‘o ' 0 Light line
'o *0. c. an, it
.o r“ . # *t # Male
.0 fl’ fl: ”1* ”I *t
0.. ** #
.3. O... Light line
.0. ....o'... Female
150 .0. ....o...
0 1 2
Generation
Figure 2. The effect of selection for lZ-week

body weight on 4-week body weight

8-week body weight (gm)

60

 

 

** Heavy line
V* i * Male
650 p «I I
p 4
p s
‘ l»
y
#1;
# I
#1
‘ 4
* 4
“¥
'*¥
it,“ a Heavy line
# .
g .0 Female
## O
* * .0.
550 # .0
*8 fl! .
#y# ..o
##t....
0.. It I“ #1:
' #
......... # t #
...00°.. ”3* Light line
’2'... Male
‘50 ..'o..
ooooooooo.... Light line
°' Female
0 1 2
Generation

Figure 3. The effect of selection for lZ-week body weight
on 8-week body weight

lZ-week body weight (gm)

 

61

 

1200
t i :k * t :t i t t a a Heavy line
*‘* Male
*
t
i
a
t
1000 a
4" fl
* # .g, 4" 2" 1w 11*
a
it} if
a u", Heavy line
........oo-°“°'" Female
* a, Light line
..o'.. tn. Male
800 ....000
U:::oooooo..........
Light line
Female
6JJO
0 1 2
Generation
Figure 4. The effect of selection for 12-week body weight

on lZ-week body weight

18-week body weight (gm).

62

 

 

. Heavy line
i * Male
*
* i
1500 a
$
$
‘
1.
fl
‘-
:6
fi
‘
I»
is
u
a
y
a a
a
fi *4!
1300 t
- it
{It
§
a
a
it
* * Light line
...-°°°°. Heavy line
1100 "0""... Female
900
0000.... Light line
Female
0 1 2
Generation

Figure 5. The effect of selection for 12-week body weight
on l8-week body weight

63

Experimental data transformation to logarithmic and
percentage scale are shown in Tables 3, 4, 5, 6 and 7.

The final conclusionsto be drawn from examining
these tables are:

l. Transformed measurement to logarithmic or percent-
age scale did not appear to give a noticeably better fit than
the actual scale.

2. There was little evidence that size genes were

acting multiplicatively.

Heritability estimates

 

The heritability estimates obtained herein were calcu-
lated from parent-offspring regression and from cumulative
effects of selection (realized heritability) techniques.

The general model for the regression of offspring on

one parent or mid-parent was considered in this study as

Yijk=u+3j+b(Xi-X)+eijk

where :

Yijk = the phenotypic value of the kth

the ith parent.

offspring of

u= overall mean of the offspring population

Sj=Sex effect, j = l for males, 2 for females

b= regression coefficient

Xi=observed parent value (sire, dam or mid-parent)
is average phenotypic value of the parent p0pulation
h

e.. =the deviation peculiar to the kt

13k progeny of parent

i and sex j.

64

Aeqemav unnun<oez Eonw oeuneoe mes anom eHoer

 

 

 

 

 

 

mm.mH «a.ma onHA
oeuooaom
oemnn
whe¢.cu hmmoqfii mm.Hn www.mn moho.o- ew.Hu
Ho.om om.o~ omem
mmm.H whoo.o+ om.o+ emao.u eooo.ou No.0:
mm.cm em.o~ enHA
oeuooaom
h>eem
N mwoq maenw unwwoz N mmoq maeno unwaoz
nH monouemwwa nH mononewmaa
meaeaem meaez
a.moweuneonon nH one .munmaes mo manuanemoa mo moonouommwo nH .maenw ounaomne
nH oemmonnxo memmoa one mnflew .enwa unwwa one nw nOHuoeHom mnnwa one enaH
h>een onu nH nonuoeaem mnan mo mnoaueuenem 03u Heume one noaueuenew omen man
no munemeonn ooxooZuwnHm eaeaem one oHeE.mo Aamv munwweB oHo heoueno ewene>< .m mgmnfi

65

.Aeeqmav unnun<oez Bonw oouneoe me3 Show oaoefis

 

 

 

 

 

 

 

Hm.nma Ne.HmH onHA
oeuooaem
ocean
om.omu omob.0u mm.oqu mm.mH- mwwo.ou mm.oeu
NN.NmH Hm.N- omem
mH.N mmmo.o+ Ha.¢a+ Nw.m moao.o+ m.m+
mm.HH~ Hm.omm enHA
oouuoaem
h>eem
N .mmOA maeno unwwez N mwou maenu uaneB
nH meononemmnn na meoneHeMMHo
meaeaem moaez
a.meweuneonen nH one .munmwe3 mo manuwnewoa mo moonenommwo n“ .maeuw eunHomoe
nw oemmennxe memmoa one mnHew .enHH unwed enu nw noauooaem mnnwe one onHH
m>een enu nw nowuooaem mnan mo mnOHueHonew 03u Heume one nowuenenem omen enu
mo munemeonn oexernmnwm eHeEem one eHeE mo Aawv munwwe3 xee3ue owene>< .e mam<e

66

.Aeeemav unnun<oez Eonm oooneoe me3 Show maneet

 

 

 

 

 

 

 

mo.HHe mm.eme ean
oeuooaom
. oewnn
mm mat ammo.bu NN.NNI MH.QHI memo.0u mm.Hmu
He.mwe Hm.mmm omem
mm.mH memo.o+ oo.wn+ mH.mH Naoo.o+ Ha.nw+
Nq.nom No.moo oan
oeuooaem
h>eem
N mwoq maeno uanoB N awoq maenu unwwez
nH eoneHoMMHn na eonenommwa
meaeaeh meHeZ
a.meweuneonon nH one .munwfle3 mo manuaneon mo meonenemmao nw .meeuw ounaomne
nH oommennxe memmoa one mnwew .enfiH unwfia onu nw nowuooaee ennwa one enwa
m>een enu nH noauooaem mnan mo enoauenenow can Heume one nowuenonew omen
enu mo munemeenn oexeruwnwm oHeEem one maea mo Aawv munwwe3 xeeSuw oweno>< .m mqm<H

67

.Aeeemav unnun<oez Eonm oeuneoe meB Show eaoeat

 

 

 

 

ou.oao Hm.omm oan
oeuooaem
semen

mouth eHwo.ou HH.NNHu mm.HHc ewmo.o: Ho.oOHn
mm.mem Nw.Nmm eeem

wm.mH mmmo.o+ on.oma+ mm.wa mmno.o+ Hm.oNH+
mm.oww mm.mOHH onHA
oeuoeaem
h>eem

N mwoA enema unwflez N mwoa maenu unwwoz

 

nH monouemmaa

nw eoneuemmwn

 

meHeEom

meHeE

 

«.meweuneouen nw
one .munwwe3.mo manuwnewoa mo meoneuommao nw .waenw eunaomoe na oemmennxe
eeemoa one mnweu .onwa unwaa one n“ nowuoeaem ennwa one onfia h>een
one na noauoeaem mnan mo mnowueuonew asp noume one nowuenenew omen enu

mo munemeenn ooxooZumnwm eHeaem one eaea mo ABwv eunwwe3 xee3uNH oweno>< .o mum<H

68

.Aeeemav unnun<oe2 Eonm ooumeoe meB Ehom waneBs

 

 

 

 

N¢.emw Hm.mmHH enaq
oeuooaom
Bowen

mmme-mmno.ou mnwwmau ,mmeHniNmoo.ou mw.HwH:
mo.awm mm.HemH emem
Hm.NH mono.o+ No.moa+ ww.eH Nooo.o+ mo.mma+ l.
Hw.HmHH mm.aema onwg
oeuoeaom
h>eem

N mwoq maenu unwwoz N mwoq maenu unwaoz

 

nw oonenemmwo

nH mononemmwa

 

meaeaem

moaez

 

a.meweuneonon nH
one .munwwos mo manuwnewoa mo moonenommwo nH .maeuw eunHOmne nw oemmennxe
memmoa one enfiew .enHH unwaa one nw nowuoeaem mnnwa.one enHH h>een
onu nH nowuoeaem mean mo mnowuenenew ozu Heume one nowueuenew omen one

mo eunemeenn oexooZIwnflm oHeEem one oHeB mo Aawv munwwe3 xeezuma ewene>< .N mqmnH

69
Estimates of the realized heritability in this study
were calculated as outlined by Falconer (1960). Realized

heritabilities were determined by the following formulae:

2 = R
h s
where:
h2 = realized heritability
R = response (gain)
S = Selection differential (intensity)

Falconer (1960) stated that "the ratio of response
to selection differential, however, has an intrinsic interest
of its own, quite apart from whether it provides a valid
estimate of the heritability. It provides the most useful
empirical description of the effectiveness of selection,
which allows comparison of different experiments to be made,
even when the intensity of selection is not the same." Lush
(1945) has defined selection differential as the difference
between the mean of the selected animals and the mean of the
population in which they were born. The cumulative selec-
tion differential at any one generation is the selection
differential for the generation added to the sum of the differ-
ential for all previous generations.

Heritability estimates calculated by parent-offspring
regression techniques for body weights at one-day, 4-weeks,

8-weeks, lZ-weeks and l8-weeks of age for the first generation

70
(where heavy and light selected lines were considered as
one group), second generation heavy and light selected
lines, where sex differences between males and females
were adjusted are shown in Table 8.

Average heritabilities and standard errors for the
first generation of selection were .66 t .11, .44 t .08,

.66 f .07, .50 t .04 and .88 f .04 for body weights at one-
day, 4-weeks, 8-weeks, 12-weeks and l8-weeks of age,respect-
ively (Table 8). For the second generation heavy selected
line they were equal to -.07 t .11, 1.74 t .46, .79 t .27,
.31 t .31 and .33 f .16 for body weights at the same ages as
stated before, respectively, while for the second generation
light selected line they were equal to 1.05 t .29, .36 t .24,
.41 t .23, .20 t .42 and .09 t .34 at the above mentioned
time intervals, respectively (Table 8).

If estimates of heritability that fall outside the
possible biological range of heritability are omitted from
the average calculations then the average heritability esti-
mates and their associated standard errors for the first
generation of selection would be .47 t .l, .44 t .08, .66 t
.07, .50 t .04 and .63 t .03 for body weights at one-day,
4-weeks, 8-weeks, lZ-weeks and 18-weeks of age, respectively.
Heritability estimates for the second generation heavy
selected line at these time intervals would be .29 t .18,

.64 T .21, .46 T .24, .77 T .26 and .33 T .16, respectively,

while for the second generation light selected line they were

71

 

 

on o a S o No a So So a Go owouoes nag
no a So So a no So a 8o: omega
so a no no a So So a no use?
season o . seasons 8 3o season
So a go no a go So a io fleas. gotten sons so So sworn
so a So. So a «so So a Sn amass season Peso so So 983.3
so a So no a no So a go omens.
no a no no a no So a no some»:
033.3 a tomatoes so Bo 9.1.272
no a So So a Sn So a 8o uses: semen Pots so so satin
So a So So a Go. Bo a no Ewes» sonata Pane so Bo 98in
no a so no a 2o So a to settle.
So a no So s So So a go so?
seesaw Resonate so So seat.»
so ... So no a 34 So 4 To use”? vests Fons so So sees.»
So a So no Homo So a mo uses? sooio same so Bo sears
«Nd « end 36 a #4 mod n 136 030%
so a So So a to So a no two:
fists assesses so 3o 9.33
So a So go a go So a no use? soars Boas so So sense
no 4 So- no a So So a go see“! snooze Pans so So sears
no a on no a So. no a so omega
So a 2o so a So. So a to so?
.Dflounosfunwumraqa.kooaoinaouno
so a mo so a no. no a on use? as 96 sons 8 so as use
So a So no ... no So 4 3o assess so 96 Ease so So so 95
mafia enonmouqqoxaaznse annwanxome
_maOQmoieo3A nhnueanmm.snoom omnoagfixvunoflmmexxem

sknueHHUwisxoom
hnduepnn.oaflxanm
u. 33333.8:

“nunupHnooaflxanm
we bansfiflsi

tonnage

“snooqoxwmosnnunnxuw
ueHmwuou.§Hca.oaflxaflm

1.. Dansflsuom

unwoksmnonwfiflumonkdumflmaz

 

h>eon

.Nao>auooneeu .enHH oeuooaee unwaa
nowueuenew onoooe .nowueuenew unnaw can now .mHo>«uuoneoH .owe mo execs

nowueuenew onoooe one onwa oeuooaem

umH one exoosuua .exeoslw .mxoezue .meo eno ue unwae3.e.uneuennow8 one when .aeo
no unwwos.wnaunmmmo mo noaeeouweu ho oeueawumo me House oueoneue H huwaaneuwuem .w mnm<H

72
equal to .47 T .42, .59 T .24, .41 T .23, .20 T

.42 and .59
t .28, respectively.

1 These results seem to indicate that heritability
estimates vary between rather wide limits, where many esti-
mates fall beyond the possible biological range of herit-
ability. Under the conditions of our study the best explana-
tion of the fluctuations of these heritability estimates
would be large sampling errors due to small number of dams,
sires and progeny.

At the time regression of offspring on mean of parents
was considered "the most nearly unbiased estimate (short of
selection experiments) of effective heritability" by
Dickerson (1959) because it is an excellent technique in re-
ducing sampling errors much more consistent and reliable esti-
mates of heritability were obtained from regression of off-
spring on mid-parents in comparison to double regression of
offspring on dam and double regression of offspring on sire.

Examining heritability estimates obtained from regres-
sion of offspring on mid-parents would reveal that most of
them fall within the possible biological range of heritability
except for the case of offspring's one-day weight which could
be due to a combination of genetic and environmental factors.

Realized heritability estimates of lZ-week old body
weights for males and females of the light and heavy selected
lines for the first, second and both generations of selection

obtained in this study are given in Table 9. The results

73

.cofluoeaem mo.:oauenenew onooom one umuwm enu.aonm maeaucenemmao nowuooaom m>Hueanasoo<

 

 

 

 

 

 

 

 

 

 

 

N
.nofiuooaem mo_n0Huenenew onooem one umnflm esu_aoym noncommeu_n6fiuoeaem e>Hueanasoo¢w
too So So So 2o Bo- sweats
3o mmo no No no So nonsense
Tenses
Noam? mnoom- 3.5+ whom- 38$ Soon. to
assessment
sfiooonom
sofl+ Hnofl- 8.3+ moon- $.81 «Non- a3 ossaoom
moaefiom meaeaom meaesom moaeaem moaeaem moaenmm
«no So 8.- So So So. bananas
newness
Son? «not? 3.5+ Room- 38? goon- eev
assesses
SOHUUOHmm
non? no.8? an- Noon... 3.5+ so? so ossosaos
sons: sons: sons: mafia sons: sows
endH mafia ”Sn; snug “nag mafia

mooooaow boom soooonow used

ghuunmaewFZOm

Hafioflmwwmzmflwomfimaownnnnq unfiommxwhamfli omfixzowunan
nnfiunnxmw_¥noom

nhnunnxownnnuh

 

.hae>«uoenmon .nowuoeaem mo enowuenenew noon one onooom .umnwm enu How menHH
oeuooaem h>eon one unwwa on» mo meaeaem one meaea_oao xooBuNH Mom munwwoz hoop mo
eeueaaume huwawoeuwnen oeeaaeon one maewunenommao nowuooaem .momnonmou nowuoeaem .m mnm<9

74
indicated that average realized heritabilities were .25 and
.33 in the light selected line for males and females, res-
pectively, while in the heavy selected line they were .47
and .38, respectively. If negative values of heritability
estimates are omitted from statistical analysis, then aver-
age realized heritabilities would be .50 and .33 in males and
females of the light selected line, respectively, while
these estimates would be equal to .71 and .38 in the heavy
selected line for males and females, respectively. In general
these estimates are not in agreement with findings reported by
Maloney (1963b), Maloney and Gilbreath (1966) and Maloney gt El-
(1967) who reported much lower values for heritability estimates
at 12—weeks of age.

Data reported in Table 9 have shown that a single
generation of two-way selection provides a very unreliable
estimate of heritability in a p0pulation of this size. As the
generations proceed the estimate from the total response be-
comes more and more reliable.

Heritability estimates obtained herein from.the cumu-
lative effects of selection and parent-offspring regression
techniques were quite high which suggests the existence of
high additive genetic variance. This will indicate that mass
selection would be the best single procedure to use to select
for body weight to ensure that highest genetic gains for body

weight are obtained.

75
Duration of Fertility

Fertility problems in chickens and turkeys have been
examined by numerous investigators, while they have received
very little attention in other species of poultry.

Several researchers have shown that spermatozoa can
live in the hen oviduct and remain active for several weeks.
Curtis and Lambert (1929) quoted Chappelier (1914) who stated
that duration of fertility in chickens ranges from 10-18 days
and in ducks from 7-11 days. Curtis and Lambert (1929) sum-
marized the work of other authors by stating "Some variation
is noted in the duration of fertility reported. Crew (1926)
reports 23 days in one case and 20 in another as mentioned in
the 1926 report. He had, however, noted a duration of 32
days in an earlier investigation. Dunn (1927) reports a maxi-
mum of about one month with two weeks as the average. Moore
(1916) gives 15 days as a limit, and Kaupp (1919) and Gilbert
(1904) 12 days. Gray (1916) suggests 15-18 days. Laurie
(1919) finds 17 days and Lienhardt (1923) says that it is not
over 30. Payne (1914) reports 16 days, Philips (1918) 15 days,
Rolf (1916) 14 days, and Waite (1911) 15 and 20 days after
the removal of the male from a flock. These findings all fall
within a range of 12-30 days with the greater number of cases
between 15 and 20."

Curtis and Lambert (1929) reported from their study of
fertility in poultry that mean duration of fertility was about

11 days with 21 daysas the extreme duration, while 15 days

76

as an average duration of fertility from single mating with
29 days as the maximum.duration of fertility was reported
by Nicolaides (1934).

As was stated in the procedure section, gathering
eggs from previous pullet breeders in the base generation con-
tinued for 6 weeks (from November 1 until December 14, 1975)
after removal of males from the mating pens. Regarding the
duration of fertility, data from 16 pullet breeders which con-
tinued to lay eggs after the removal of the males show that
laying of the last fertile egg from a single mating varied
from 10-21 days with an average of about 15 days (Table 10).
In general these results are in close agreement with most of

.

the published results that have been reported by previous

investigators.

Relationship of egg weight to chick weight at hatching

Data from one hundred and eighty-six one day old con-
trol pheasant chicks (80 males + 86 females) and one hundred
forty-seven one-day old second generation chicks (19 males
and 25 females from the light selected line + 59 males and 44
females from the heavy selected line) were used to determine
the relationship of egg weight to chick weight at hatching.

From the results that were summarized in Table 11, it
seems that the body weight of the chick at hatching time
depends upon the weight of the egg from which that chick

hatches.

77

TABLE 10. Duration of fertility

 

 

Female Total eggs laid after Time last fer-
number removal of the male tile egg was
(Nov.l-Dec.12, 1975) laid after
removal of the
male (Day)

11057 21 17
11302 27 18
11189 24 17
11255 21 14
10945 22 16
11004 12 10
10931 18 15
11342 21 15
11299 23 17
11137 8 13
11264 17 15
11030 21 ' 14
10968 24 21
11272 21 18
11284 19 14
11139 14 12

 

Average 15

 

78

An intimate degree of association between egg weight
and day-old chick weight was observed, where positive
coefficient of correlation was .91, .86, .83, .76, .81 and .78
for control males, control females, second generation light
selected line males, second generation light selected line
females, second generation heavy selected line males and
second generation heavy selected line females, respectively.
These results confirmed findings reported previously by
Halbersleben and Mussehl (1922), Upp (1928) and Wiley (1950).

In Table 11 is given the mean weight of the chicks
hatched from the control group and the second generation which
were used in this study and the mean weight of eggs used.
From these results it was concluded that chick weight at hatch-
ing time represents 64-67 percent of the egg from which it
hatched and that heavier eggs produced heavier chicks. It may
be noted that these results confirmed Halbersleben and Mussehl
(1922) and Hutt (1949) reports.

The slope and the Y—intercept for the regression of
chick weight on egg weight that wenacharacterized in Table 11
were calculated by using HP. 32E calculator. These statisti-
cal parameters were calculated by using the following equations
which were already programmed into the calculator.

Slope of the least square line = n2XY - ZXZY
' nXX2 - (XX)2

Y-intercept of the least square line = 21sz2 - ZXZXY

nZX2 - (EX)2

 

 

79

 

eeHeEew mnHH

 

«mm. mo.~ Hem. «0.00 em.om mn.nm «a emsomnmm m>mma
nowueuenew onooem
meaen enHH
men. m~.m- mom. em.oo no.0m mw.om an emuumnmm m>mmn
nowueuonow onooem
moHeaem enHH
eon. NN.N mom. mm.ee wo.mn eo.m~ mm emuomnmm unwnn
nOHueHenew onoomm
modes enfla
0mm. Hm.¢u wmm. om.eo em.mH mm.m~ ma oeuooaee unwwa
nOHueHenew onooem
oqo. mm.o «ow. mm.mo n¢.HN mm.~m ow moaeaem Houunoo
wwo. no.Hu mom. wm.~o mo.HN ma.~m ow meaea Houunoo
unwwea xofino unwfle3 Aamv
oHou%eo ou wwe mo unmwe3
enHH uneo unmwe3 mwe unwfioS .oHo Anwv maeno
enu mo uueunw mo coauea xofino neoua omen ammo mo uw>flonfl
macaw -w neaenuoo unmohem eweue>< unwwe3 neoz. mo .02

 

mawnenowueaeu unwwe3 xowno oHOumeo ou unwwes wwe mo hueaanm .aH mqmnH

80
Eggproduction

 

Daily individual egg production was recorded for all
females selected as parental stock in base and first
generation only.

Mortality that occurred among the selected female
parental stock at time where egg production was recorded
resulted in a loss of 10 females in the base generation, where
7 females were lost from.the light selected line and 3 females
from the heavy selected line, while in the first generation 7
females were lost, where 5 and 2 females were lost from.the
light and heavy selected line, respectively.

From the individual egg production records, hen-housed
and hen-day egg production were calculated by using the

following formulae:

_ Total eggproduction
H'H' - Number of hen housed 100

= Emiresfizadszgim x

Table 12 shows that hen-housed egg production for the
heavy females selected as parental stock was 60.63 and 48.57
percent for base and first generation, respectively. For the
light selected females it was 48.83 and 34.19 percent for the
same generations, respectively. Hen-day egg production for
heavy females selected as parental stock was 61.87 and 51.61
percent for base and first generation, respectively. For the
light selected females it was 56.70 and 39.66 percent for the

same generations, respectively.

81
Although hen-day and hen-housed egg production was
lower for the first generation than for the base generation
for both heavy and light selected lines, no conclusion can
be drawn that this difference was due to genetics because egg
production records for the control groups were not available

for statistical comparisons.

Mortality and Cause of Death

 

Mortality calculation was expressed as a percent of
the total birds that died to the total chicks housed for each
generation separately. Data from Table 13 show that percent
mortality was 19.58, 31.93, 37.03 and 24.20 for the base,
first, second generation and control population, respectively.
Both heavy and light selected lines were grouped together in
the first generation and in the second generation when percent
mortality was calculated.

Chi—square analyses have shown that one may have 99.9
percent confidence that mortality is not independent of
selection. Bonferroni chi-square analysis was performed to
check which populations differ from the others (p < .01), where
the following comparisons were investigated:

1) Control vs. base generation

2) Control vs. first generation

3) Control vs. second generation

4) Base generation vs. first generation

5) Base generation vs. second generation

6) First generation vs. second generation

82

TABLE 12. Hen-housed and hen-day egg production for base and
first generation females selected as parental

 

 

stock.

Egg production Base generation First generation
production (%) production (%)

Hen-housed (for
heavy selected 60.63 48.57
females)
Hen-housed (for
light selected 48.83 34.19
females)
Hen-day (for heavy
selected (females) 61.87 51.61
Hen-day (for light
selected females) 56.70 39.66

 

TABLE 13. Number of birds hatched, survived, died and percent
mortality for the total period of the experiment
(October 1,1974» -March 2, 1977)

 

Generation Number Number Number Percent of
Hatched Alive Dead Mortality

Base a

generation 480 386 94 19.58

(1975)

First , b

generation 573 390 183 31.93 C

(1976)

Second

generation 405 255 150 37.03c

(1977) '

Control 219 166 53 24.20ab

(1977)

 

NOTE: 1) Values with different superscript differ significant-
ly, p < 0.01).
2) Mortality was recorded up to 18 weeks of age.

83
Highly statistical differences (p < 0.01) were found between
base generation and first generation, base generation and
second generation and, finally, between control and second
generation (Table 13).

The evidence so far suggests that two-way response to
artificial selection for body weight in Ring-Necked pheasant
depresses livability. This is in accord with Falconer (1953a,
1960) and Nordskog gt a1. (1964, 1974), who stated that total
reproductive fitness is expected to decline when artificial
selection for any character upsets equilibrium gene frequen-
cies. Since livability is a component of the total reproduc-
tive fitness, it is not surprising that this character may
decline when artificial selection changes the population mean
in either direction.

Reports of laboratory examinations received from vet-
erinary diagnostic laboratories, Department of Pathology, M.S.U.
have indicated that according to the history, gross lesions and
laboratory findings, diagnosis was characterized into air
sacculitis, cecal coccidiosis, emaciation, necrotic core in
cecum, pericarditis, peritonitis, pneumonia, post-mortem de-
composition and pulmonary hemorrhage. These diagnoses were

characterized about evenly among all generations.

SUMMARY AND CONCLUSIONS

Individual selection for heavy and light selected
lines at lZ-weeks of age which was practiced for two genera-
tions in Ring-Necked pheasant populations have resulted in
mean body weight differences of about 2, 49, 168, 283 and 381 gm
in the males and 2, 54, 156, 264 and 327 gm in the females at
one-day, 4-weeks, 8-weeks, lZ-weeks and 18-weeks of age, res-
pectively, between the two diverse selected lines.

The heavy selected line gained more weight by plus
selection than was lost from the light selected line by minus
selection. In addition to that males gained or lost more
weight than females.

Progress due to selection for body weight in the light
and heavy selected lines appears to be erratic. This irregular-
ity is similar to that reported in other selection experiments.

Experimental data transformation to logarithmic and
percentage scale did not appear to give a noticeably better
fit than the actual scale. In addition to that there was
little evidence that size genes were acting multiplicatively.

Heritability estimates obtained in this study were
calculated from parent-offspring regression and from cumulative

effects of selection (realized heritability) techniques.

84

85

After omitting all values that fall outside the
possible biological range of heritability, then average
heritability estimates calculated from parent-offspring
regression techniques for the first generation of selection
would be equal to .47 T .1, .44 T .08, .66 T .07, .50 T .04
and .63 t .03 for body weights at one-day, 4-weeks, 8-weeks,
lZ-weeks, and 18-weeks of age, respectively. Heritability
estimates for the second generation heavy selected line at
these time intervals would be .29 t .18, .64 t .21, .46 t
.24, .77 t .26 and .33 f .16, respectively, while for the
second generation light selected line they were equal to .47
T .42, .59 T .24, .41 T .23, .20 T .42 and .59 T .08, res-
pectively.

The best explanation of fluctuations of these values
would be large sampling errors due to small number of dams,
sires, and progeny.

Much more consistent and reliable estimates of herit-
ability were obtained from regression of offspring on mid-
parents in comparison to double regression of offspring on
dam and double regression of offspring on sire.

Average realized heritability estimates after negative
heritability estimates were omitted from the statistical
analysis were found to be .50 and .33 in males and females of
the light selected 1ine,respectively, while they were equal
to .71 and .38 in the heavy selected line for males and

females, respectively.

86

These results suggest the existence of high addi-
tive genetic variance, which in turn indicates that mass
selection would be the best method to ensure that highest
genetic gains for body weight are obtained.

Duration of fertility ranged from 10-21 days with an
average of about 15 days.

An intimate degree of association between egg weight
and day-old chick weight was observed, where positive co-
efficient of correlation was .91, .86, .83, .76, .81 and .78
for control males, control females, second generation light
selected line males, second generation light selected line
females, second generation heavy selected line males and
second generation heavy selected line females, respectively.
It was also noted that chick weight at hatching time repre-
sents 64-67 percent of the weight of the egg from which it
hatched and that heavier eggs produced heavier chicks.

Hen-housed egg production for the heavy females
selected as parental stock was 60.63 and 48.57 percent for
base and first generation, respectively. For the light
selected females it was 48.83 and 34.19 percent for the same
generations, respectively. Hen-day egg production for heavy
females selected as parental stock was 61.87 and 51.61 per-
cent for base and first generation, respectively. For the
light selected females it was 56.70 and 39.66 percent for the

same generations, respectively.

87

Percent mortality was 19.58, 31.93, 37.03 and 24.20
for the base, first, second generation and control popula-
tion, respectively. Chi-square analyses have shown that one
may have 99.9 percent confidence that mortality is not in-
dependent of selection.

Highly statistical differences (p < 0.01) in mortal—
ity were found between base generation and first generation,
base generation and second generation and, finally, between
control and second generation.

Since livability is a component of the total reproduc-
tive fitness, it is not surprising that this character may
decline when artificial selection for any trait upsets equili-
brium gene frequencies and results in decline of total repro-

ductive fitness.

BIBLIOGRAPHY

BIBLIOGRAPHY

Abplanalp, H., and I.L. Kosin. 1952. Heritability of body
measurement in turkeys. Poultry Sci. 31: 781-791.

Abplanalp, H., F.X. Ogasawara and V.S. Asmundson. 1963.
Influence of selection for body weight at different
ages on growth of turkeys. British Poultry Sci. 4:
71-82.

Amer, M.F. 1965. Heritability of body weight in Fayoumi.
Poultry Sci. 44: 741-744.

Asmundson, V.S. 1942. Crossbreeding and heterosis in
turkeys. Poultry Sci. 21:311-316.

Asmundson, V.S. 1944. Measuring strain differences in the
conformation of turkeys. Poultry Sci. 23:21-29.

Asmundson, V.S. 1945. Inheritance of breast width in
-turkeys. Poultry Sci. 24:150-154.

Asmundson, V.S. 1948. Inherited differences in weight and
conformation of Bronze turkeys. Poultry Sci. 27:
695-708.

Asmundson, V.S. and I.M. Lerner. 1933. Inheritance of rate
of growth in domestic fowl II. Genetic variation in
growth of Leghorns. Poultry Sci. 12:250-255.

Asmundson, V.S. and I.M. Lerner. 1940. Growth of turkeys.

I. Influence of strain, sex and ration. Poultry Sci.
19:49-54.

Asmundson, V.S. and C.F. Pun. 1954a. Inheritance of rate
of growth in Bronze turkeys. Poultry Sci. 33:411-416.

Asmundson, V.S. and C.F. Pun. 1954b. Growth of Bronze
turkeys. Poultry Sci. 33: 981-986.

Barker, J.S.F. 1958a. Simulation of genetic systems by auto-
matic digital computer. III. Selection between

alleles at an autosomal locus. Aust. J. Biol. Sci.
11: 603-612.

88

89

Barker, J.S.F. 1958b. Simulation of genetic systems by
automatic digital computers. IV. Selection between
alleles at a sex-linked locus. Aust. J. Biol. Sci.
11: 613-625.

Becker, WnA. 1975. Manual of quantitative genetics.
Washington State University Press, Pullman, Washington,
170 pages.

 

Becker, W.A. and G.E. Bearse. 1973. Selection for high and
low percentages of chicken eggs with blood spots.
British Poultry Sci. 14: 31-47.

Bell, A.E., and H.W. McNary. 1963. Genetic correlation and
asymmetry of the correlated response from selection for
increased body weight of Tribolium in two environments.
Proceedings of the XI International Congress of
Genetics, The Hague, Netherlands, 256.

Berger, P.J., and W.R. Harvey. 1975. Realized genetic para-
meters from index selection in mice. J. of Animal Sci.
40: 38-47.

Bogyo, T.P., and W.A. Becker. 1963. Exact confidence inter-
vals for genetic heritability estimated from paternal
half-sib correlations. Biometrics 19: 494-496.

Bohren, B.B., W.G. Hill and A. Robertson. 1966. Some obser-
vations on asymmetrical correlated responses to selection.
Genetical Research 7: 44-57.

Bohren, B.B., H.E. McKean and Y. Yamada. 1961. Relative effi-
ciencies of heritability estimates based on regression
of offspring on parent. Biometrics 17: 481-491.

Broemeling, L.D. 1969. Confidence intervals for measures of
heritability. Biometrics 25: 424-427.

Bruns, E., and W.R. Harvey. 1976. Effects of varying selec-
tion intensity for two traits on estimation of realized
genetic parameters. J. Animal Sci. 42: 291-298.

Brunson, C.C., G.F. Godfrey and B.L. Goodman. 1955. Types of
gene action in the inheritance of ten-week body weight
and breast angle in broilers. Poultry Sci. 34: 1183.
(Abstract)

Brunson, C.C., G.F. Godfrey, and B.L. Goodman. 1956. Types
of gene action in the heritability of ten-week body

weight and breast angle in broilers. Poultry Sci. 35:
524-532.

90

Bumgardner, H.L., and C.S. Shaffner. 1954. The heritability
of body weight in turkeys. Poultry Sci. 33: 601-606.

Burrows, P.M. 1972. Expected selection differentials for
directional selection. Biometrics 28: 1091-1100.

Buvanendran, V. 1969. The heritability and genetic correla-
tions of sexual dimorphism for 10-week weight in
poultry. British Poultry Sci. 10: 321-325.

Carte, I.F., and P.B. Siegel. 1968. Correlated-heritabilities
of unselected traits: A check on procedure, Poultry
Sci. 47: 1821-1827.

Chai, C.K. 1956. Analysis of quantitative inheritance of
body size in mice. 11. Gene action and segregation.
Genetics 41: 165-178.

Cheung, T.K. and R.J. Parker. 1974. Effect of selection on
heritability and genetic correlation of two quantita-
tive traits in mice. Can. J. Genet. Cytol. 16: 599-609.

Clayton, G.A., G.R. Knight, J.A. Morris and A. Robertson. 1957.
An experimental check on quantitative genetical theory.
III. Correlated responses. J. Genetics 55: 171-180.

Cockerham, C.C. 1954. An extension of the concept of parti-
tioning hereditary variance for analysis of covariances
between relatives when epistasis is present. Genetics
39: 859-882.

Collins, WLM., and H. Abplanalp. 1965. Mass selection for
body weight in Japanese quail. Genetics 52: 436-437.

Collins, W.M., H. Abplanalp, and W.G. Hill. 1970. Mass selec-
tion for body weight in quail. Poultry Sci. 49: 926-
933.

Comstock, R.E. 1956. Genetic variance for eight week weight
in strains and crosses. Poultry Sci. 35: 1137 (Abstract)

Comstock, R.E., M. Singh and F.D. Enfield. 1963. Selection
for growth in mice: Crossbred Performance. J. of
Animal Sci. 22: 1109 (Abstract)

Cook, R.E., W.L. Blow, C.C. Cockerham and E.W. Glazener. 1962.
Improvement of reproductive traits and body measure-
ments of turkeys. Poultry Sci. 41: 556-563.

Curtis, V., and W.V. Lambert. 1929. A'study of fertility in
poultry. Poultry Sci. 8: 142-150.

91

Dev, D.S., R.G. Jaap and W.R. Harvey. 1969. Results of
selection for eight-week body weight in three broiler
populations of chickens. Poultry Sci. 48: 1336-1348.

Dickerson, G.E. 1955. Genetic slippage in response to
selection for multiple objectives. Cold Spring Harbor
Symposia on Quantitative Biology 20: 213-224.

Dickerson, G.E. 1959. Techniques for research in quantitative
animal genetics. In Techniques and Procedures in
Animal Production Research. Am. Soc. Anim. Prod.
Publication. 56-104.

Dickinson, A.G., and J.L. Jinks. 1956. A generalized analysis
of diallel crosses. Genetics 41: 65-78.

Dillard, E.U., G.E. Dickerson and W.F. Lamoreux. 1953. Herit-
abilities of egg and meat production qualities and
their genetic and environmental relationships in New
Hampshire pullets. Poultry Sci. 32: 897. (Abstract)

El-Ibiary, H.M., and C.S. Shaffner. 1951. The effect of in-
duced hypothyroidism on the genetics of growth in the
chicken. Poultry Sci. 30: 435-444.

Falconer, D.S. 1953a. Selection for large and small size in
mice. J. Genetics 51: 470-501.

Falconer, D.S. 1953b. Asymmetrical response in selection
experiments. Symposium on genetics of population
structure. Pavia, Italy, 16-41.

Falconer, D.S. 1954. Validity of the theory of genetic corre-
lation. J. Heredity 45: 42-45.

Falconer, D.S. 1960a. Introduction to Quantitative Genetics.
Ronald Press Co., NewfiYofk, 365p.

Falconer, D.S. 1960b. Selection of mice for growth on high

and low planes of nutrition. Genetical Research 1: 91-
113.

Falconer, D.S., and J.W.B. King. 1953. A study of selection
limits in the mouse. J. Genetics 51: 561-581.

Falconer, D.S., and M. Latyszewski. 1952. The environment in
relation to selection for size in mice. J. Genetics

51: 67-80.

Festing, M.F., and A.W. Nordskog. 1967. Response to selection
for body weight and egg weight in chickens. Genetics
55: 219-231.

92

Fisher, RaA. 1918. The correlation between relatives on
the supposition of Mendelian inheritance. Roy. Soc.
Edin. Tran. 52, part 2: 399-433.

Fisher, R.A. 1930. The genetical theory of natural selection.
Oxford Clarendon Press. 272p.

Fisher, R.A., F.R. Immer and O. Tedin. 1932. The genetical
interpretation of statistics of the third degree in

the study of quantitative inheritance. Genetics 17:
107-124.

Fraser, A.S. 1957a. Simulation of genetic systems by auto-
matic digital computers. I. Introduction. Aust. J.
Biol. Sci. 10: 484-491.

Fraser, A.S. 1957b. Simulation of genetic systems by auto-
matic digital computers. II. Effects of linkage on
rates of advance under selection. Aust. J. Biol. Sci.
10: 492-499.

Fraser, A.S. 1960a. Simulation of genetic systems by auto-
matic digital computer. 5. Linkage, Dominance and
Epistasis. In Biometrical Genetics, Kempthorne, 0. Ed.,
Pergammon Press, New‘York, 70-83.

 

Fraser, A.S. 1960b. Simulation of genetic systems by auto-
matic digital computers. VI. Epistasis. Aust. J.
Biol. Sci. 13: 150-162.

Fraser, A.S. 1960c. Simulation of genetic systems by auto-
matic digital computers. VII. Effects of reproductive
rate and intensity of selection on genetic structure.
Aust. J. Biol. Sci. 13: 344-350.

Friars, G.W., B.B. Bohren and H.E. McKean. 1962. Time trends
in estimates of genetic parameters in a p0pu1ation of

chickens subjected to multiple objective selection.
Poultry Sci. 41: 1773-1784.

Funk, E.M. 1930. Rate of growth in Bronze and White Holland
turkeys. Poultry Sci. 9: 343-355.

Gaffney, L.J. 1966. Studies on growth rate and estimation
of the heritability of body weight in broiler stock.
XIII World's Poultry Congress, p. 69.

Gill, J.L. 1965a. Effects of finite size on selection advance
in simulated genetic p0pu1ations. Aust. J. Biol. Sci.
18: 599-617.

93

Gill, J.L. 1965b. A Monte Carlo evaluation of predicted

selection response. Aust. J. Biol. Sci. 18: 999-
1007.

Gill, J.L. 1965c. Selection and linkage in simulated gene-
tic populations. Aust. J. Biol. Sci. 18: 1171-1187.

Gill, J.L. 1974. Lecture notes of statistics 422. (East
Lansing, Michigan State University).

Gill, J.L., and B.A. Clemmer. 1966. Effects of Selection
and linkage on degree of inbreeding. Aust. J. Biol.
Sci. 19: 307-317.

Glazener, E.W., W.L. Blow, C.H. Bostian and R.S. Dearstyne.
1951. Effect of inbreeding on broiler weights and
feathering in the fowl. Poultry Sci. 30: 108-112.

Godfrey, E.F. 1953. The genetic control of growth and adult

body weight in the domestic fowl. Poultry Sci. 32:
248-259.

Godfrey, G.F., and B.L. Goodman. 1955. Selection for small
and large body size in broiler chickens. Poultry Sci.
34: 1196-1197. (Abstract)

Godfrey, G.F., and B.L. Goodman. 1956. Genetic variation
and covariation in broiler body weight and breast
width. Poultry Sci. 35: 47-50.

Godfrey, G.F., and C.N. Williams. 1952. Heritability of
growth in the domestic fowl. Genetics 37: 585
(Abstract)

Goodale, H.D. 1938. A study of the inheritance of body

weight in the Albino mouse by selection. J. Heredity
29: 101-112.

Goodale, H.D. 1941. Progress report on possibilities in
progeny-test breeding. Science 94: 442-443.

Goodman, B.L., C.C. Brunson and G.F. Godfrey. 1954. Herit-
ability of 25-week body weight in turkeys. Poultry
Sci. 33: 305-307.

Goodman, B.L., and G.F. Godfrey. 1956. Heritability of body
weight in the domestic fowl. Poultry Sci. 35: 50-53.

Goodman, B.L., J.F. Grimes and R.G. Jaap. 1957. Repeatability
estimates of genetic variance within two closed-flock
strains. Poultry Sci. 36: 1121. (Abstract)

94

Goodman, B.L., and R.G. Jaap. 1960. Improving accuracy of
heritability estimates from diallel and triallel
matings in poultry. I. Eight-week body weight in
closed-flock strains. Poultry Sci. 39: 938-944.

Graybill, F.A., and W.H. Robertson. 1957. Calculating con-

fidence intervals for genetic heritability. Poultry
Sci. 36: 261-265.

Graybill, F.A., F. Martin and G. Godfrey. 1956. Confidence
intervals for variance ratios specifying genetic
heritability. Biometrics 12: 99-109.

Griffing, B. 1956. A generalized treatment of the use of
diallel crosses in quantitative inheritance. Heredity
10: 31-50.

Halbersleben, D.L., and F.E. Mussehl. 1922. Relation of egg
weight to chick weight at hatching. Poultry Sci. 1:
143-144.

Haldane, J.B.S. 1932. The Causes of Evolution. Cornell
Paperbacks, Cornell University Press, Ithaca, New York.
235p.

Hayman, B.I. 1954a. The analysis of variance of diallel
tables. Biometrics 10: 235-244.

Hayman, B.I. 1954b. The theory and analysis of diallel crosses.
Genetics 39: 789-809.

Hazel, L.N. 1943. The genetic basis for constructing selec-
tion indexes. Genetics 28: 476-490.

Hazel, L.N., M.L. Baker and C.F. Reinmiller. 1943. Genetic
and environmental correlations between the growth rates

of pigs at different ages. J. of Animal Sci. 2: 118-
128.

Hazel, L.N., and W.F. Lamoreux. 1947. Heritability, maternal
effects and nicking in relation to sexual maturity and
body weight in White Leghorns. Poultry Sci. 26: 508-
514.

Hazel, L.N., and J.L. Lush. 1942. The efficiency of three
methods of selection. J. Heredity 33: 393-399.

Henderson, G.R. 1959. Design and analysis of animal husbandry
experiments. In techniques and procedures in animal
production research. Am. Soc. Anim. Prod. Publication.
1-55.

Je:

95

Hill, W.G. 1970. Design of experiments to estimate herit-
ability by regression of offspring on selected
parents. Biometrics 26: 566-571.

Hill, W.G. 1971. Design and efficiency of selection experi-
ments for estimating genetic parameters. Biometrics
27: 293-311.

Hill, W.G. 1972. Estimation of realized heritabilities from
selection experiments. 1. Divergent selection. .
Biometrics 28: 747-765. 1

Hill, W.G., and F.W. Nicholas. 1974. Estimation of herit- :
ability by both regression of offspring on parent

and intra-class correlation of sibs in one experiment.
Biometrics 30: 447-468.

 

Hurry, H.E., and A.W. Nordskog. 1953. A genetic analysis of
chick feathering and its influence on growth rate.
Poultry Sci. 32: 18-25.

Hutt, F.B. 1949. Genetics of the Fowl. McGraw-Hill Book Co.,
New York, 590p.

Hutt, F.B. 1959. Sex-linked dwarfism in the fowl. J.
Heredity 50: 209-221.

Ideta, G., and P.B. Siegel. 1966a. Selection for body weight
at eight weeks of age. 3. Realized heritabilities of
unselected traits. Poultry Sci. 45: 923-933.

Ideta, G., and P.B. Siegel. 1966b. Selection for body weight
at eight weeks of age. 4. Phenotypic, genetic and
environmental correlations between selected and un-
selected traits. Poultry Sci. 45: 933-939.

Jaap, R.G. 1938. Estimating the influence of heredity on the
tarso-metatarsal length of the domestic turkey. Proc.
Oklahoma Acad. Sci. 18: 11-13.

Jaap, R.G., and J.F. Grimes. 1956. Growth rate and plumage
color. Poultry Sci. 35: 1148-1149.

Jensen, B.L., and G.R. Barr. 1971. Standard errors of herit-
ability estimates calculated from variance component
analysis of a two-way classification. J. of Animal Sci.
32: 1069-1077.

Jerome, F.N., G.R. Henderson and S.C. Kings. 1956. Herit-
abilities, gene interactions, and correlations associ-
ated with certain traits in the domestic fowl. Poultry
Sci. 35: 995-1013.

96

Jinks, J.L. 1954. The analysis of continuous variation in
a diallel cross of Nicotiana Rustica varieties.
Genetics 39: 767-788.

Johnson, A.S., and V.S. Asmundson. 1957a. Genetic and
environment factors affecting size of body and body
parts of turkeys. 1. The heritability and inter-
relationships of body weight and live body measure-
ments. Poultry Sci. 36: 296-301.

Johnson, A.S., and V.S. Asmundson. 1957b. Genetic and
environmental factors affecting size of body and body
parts of turkeys. 2. The relation of body weight and
certain body measurements to pectoral and tibial
muscle weights. Poultry Sci. 36: 959-966.

Johnson, A.S.,and R.S. Gowe. 1962. Modification of the
growth pattern of the domestic turkey by selection at
two ages. XIIth WOrld's Poultry Congress, pp. 57-62.

Joubert, J.J., J.E. Erasmus and J.P. Jordaan. 1974. Genetic
variability in the slaughtering characteristics of
three broiler breeds. 2. Heritability estimates.
Agroanimalia. 6: 59-60, Eng. Sum.

Kan, J., N.R. Gyles and RWM. Smith. 1959a. Non-additive gene-
tic variance of eight-week body weight as studied by
the analysis of diallel matings. Poultry Sci. 38:
486-487.

Kan, J., W.F. Krueger and J.H. Quisenberry. 1959b. Non-
additive gene effect of six broiler traits as studied
from a series of diallel matings. Poultry Sci. 38:
972-981.

Kawahara, T., and T. Inoue. 1966. Estimation of genetic para-
meters of the productive traits of Japanese Quail.
Ann. Report Nat. Inst. Genet. 16: 44.

Kawahara, T., and R. Kusaka. 1970. Variance and covariance
analysis of some traits of Japanese Quail. Ann. Rept.
Nat. Inst. Genet. 20: 116-117.

Kawahara, T., and K. Saito. 1976. Genetic parameters of organ
and body weights in the Japanese Quail. Poultry Sci.
55: 1247-1252.

Kempthorne, O. 1956. The theory of the diallel cross.
Genetics 41: 451-459.

Kempthorne, 0., and O.B. Tandon. 1953. The estimation of
heritability by regression of offspring on parent.
Biometrics 9: 90-100.

97
Kentucky. Agr. Expt. Sta. 1950. 63rd Annual Report, p. 50.

King, S.C. 1961. Inheritance of economic traits in the
Regional Cornell Control Population. Poultry Sci. 40:
975-986.

Kinney, T.B. Jr. 1969. A summary of reported estimates of
heritabilities and of genetic and phenotypic correla-
tions for traits of chickens. Washington, U.S. Govern-
ment Printing Off., 49p.

Kinney, T.B. Jr., and R.N. Shoffner. 1965. Heritability
estimates and genetic correlations among several

traits in a meat-type poultry population. Poultry Sci.
44: 1020-1032.

Kinney, T.B. Jr., and R.N. Shoffner. 1967. Phenotypic and
genetic responses to selection in a meat type poultry
p0pu1ation. Poultry Sci. 46: 900-910.

Klein, T.W., J.C. DeFries, and C.T. Finkbeiner. 1973. Herit-
ability and genetic correlation: Standard errors of

estimate and sample size. Behavior Genetics 3: 355-
364.

Knox, C.W., and S.J. Marsden.‘ 1944. The inheritance of some

quantitative characteristics in turkeys. J. Heredity
35: 89-96.

Knox, C.W., S.J. Marsden, and W.E. Shaklee. 1952. Inherit-
ance of the sex difference of body weight in turkeys.
Poultry Sci. 31: 822-825.

Kondra, P.A., and R.N. Shoffner. 1955. Heritability of some
body measurements and reproductive characters in
turkeys. Poultry Sci. 34: 1262-1267.

Krueger, W.F., R.L. Atkinson, J.H. Quisenberry and J.W.
Bradley. 1972. Heritability of body weight and con-
formation traits and their genetic association in
turkeys. Poultry Sci. 51: 1276-1282.

Krueger, W.F., G.E. Dickerson, Q.B. Kinder and H.L. Kempster.
1952. The genetic and environmental relationship of
total egg production to its components and to body
weight in the domestic fowl. Poultry Sci. 31: 922-
923. (Abstract)

Kyle, W.H., and A.B. Chapman. 1953. Experimental check of the
effectiveness of selection for a quantitative character.
Genetics 38: 421-443.

 

98

Lankford, L., and.M.R. McClung. 1952. Heritability of 10-
week weight in a broiler strain of chickens. Poultry
Sci. 31: 923. (Abstract)

Lawrence, M.J. 1964. Environment and Selection in Drosophila
‘melanogaster. Heredity 19: 105-124.

Lerner, I.M. 1946. The effect of selection for shank length
on sexual maturity and early egg weight in Single Comb
White Leghorn pullets. Poultry Sci. 25: 204-209.

Lerner, I.M. 1950. Population genetics and animal im'rove-
ment. Cambridge University Press, Cambridge, nondon,

342p.

 

Lerner, I.M. 1954. Genetic Homeostasis. John Wiley and Sons,
Inc., New York, 134p.

 

Lerner, I.M. 1958. The genetic basis of selection. John
Wiley and Sons,IInc., New York, 298p.

 

Lerner, I.M., V.S. Asmundson and D.M. Cruden. 1947. The
improvement of New Hampshire fryers. Poultry Sci. 26:
515-524.

Lerner, I.M., and E.R. Dempster. 1951. Attenuation of genetic
progress under continued selection in poultry.
Heredity 5: 75-94.

Lewontin, R.G., and L.C. Dunn. 1960. The evolutionary dynamics
of a polymorphism in the house mouse. Genetics 45:
705-722.

Lush, J.L. 1940. Intra-sire correlations or regressions of
offspring on dam as a method of estimating herit-
ability of characteristics. Proc. Am. Soc. An. Prod.,
pp. 293-301.

Lush, J.L. 1945. Animal breeding plans. Iowa State College
Press, Ames, Iowa, 443p.

 

Lush, J.L. 1948. The genetics of populations. Mimeographed
notes, Iowa State University, Ames, Iowa, 381p.

MacArthur, J.W. 1944a. Genetics of body size and related
characters. American Naturalist 78: 142-157.

MacArthur, J.W. 1944b. Genetics of body size and related
characters. II. Satellite characters associated with
body size in mice. American Naturalist 78: 224-237.

 

99

MacArthur, J.W. 1949. Selection for small and large body
size in the house mouse. Genetics 34: 194-209.

MacArthur, J.W., and L.P. Chiasson. 1945. Relative growth
in races of mice produced by selection. Growth 9:
303-315.

Magee, W.T. 1965. Estimating response to selection. J. of
Animal Sci. 24: 242-247.

Mahmoud, M.H., W.F. Krueger, J.W. Bradley, and J.H.
Quisenberry. 1965. Heritability of eight-week body
weight under two environments and related gene-
environment interactions. Poultry Sci. 44: 1395.
(Abstract)

Maloney, M1A., Jr. and J.C. Gilbreath. 1962. Selection for
body size in broiler chickens. Poultry Sci. 41: 1661.
(Abstract)

Maloney, MMA. Jr. and J.C. Gilbreath. 1966. Selection for
differential body weight at twelve weeks of age in the
domestic fowl. Poultry Sci. 45: 1102. (Abstract)

Maloney, MQA. Jr., J.C. Gilbreath, and R.D. Morrison. 1963a.
Two-way selection for body weight in chickens.
Oklahoma Expt. Stat. Tech. Bull. T-99, 38p.

Maloney, MMA. Jr., J.C. Gilbreath, and ReD. Morrison. 1963b.
Two-way selection for body weight in chickens.

l. The effectiveness of selection for twelve-week body
weight. Poultry Sci. 42: 326-334.

Maloney, MNA. Jr., J.C. Gilbreath, and R.D. Mbrrison. 1963c.
Two-way selection for body weight in chickens.

2. The effect of selection for body weight on other
traits. Poultry Sci. 42: 334-344.

Maloney, MNA. Jr., J.C. Gilbreath, J. F. Tierce and R.D.
Morrison. 1967. Divergent selection for twelve-week

body weight in the domestic fowl. Poultry Sci. 46:
1116-1127.

Marais, C.L., and J.J. Joubert. 1964. Water fowls. Bull.
Dept. Agric. Tech. Services, South Africa, 366.

Marks, H.L. 1971. Selection for four-week body weight in

Japanese Quail under two nutritional environments.
Poultry Sci. 50: 931-937.

Marks, H.L. 1978. Long term selection for four-week body
weight in Japanese Quail under different nutritional
environments. Theoretical and Applied Genetics 52:
105-111.

 

100

Marks, H.L., and T.B. Kinney, Jr. 1964. Estimates of some
genetic parameters in Coturnix Quail. Poultry Sci.
43: 1338.(Abstract)

Marks, H.L., and P.D. Lepore. 1968. Growth rate inheritance
in Japanese Quail. 2. Early responses to selection
under different nutritional environments. Poultry
Sci. 47: 1540-1546.

Martin, G.A., and A.B. Bell. 1960. An experimental check on
the accuracy of response during selection. In Big-
metrical Genetics, Kempthorne, 0., Ed., Pergammon
Press, New York, 178-187.

 

Martin, G.A., E.W. Glazener and W.L. Blow. 1953. Efficiency
of selection for broiler growth at various ages.
Poultry Sci. 32: 716-720.

Mather, K. 1949. Biometrical Genetics, Dover Publications
Inc., New York, 158p.

 

Mather, K., and B.J. Harrison. 1949. The manifold effect of
selection. Heredity 3: 1-52.

McCartney, M.G. 1955. Heritability and genetic correlations
of body weights of White Holland turkeys. Poultry Sci.
34: 617-621.

McCartney, M.G. 1961. Heritabilities and correlations for
body weight and conformation in a random bred popula-
tion of turkeys. Poultry Sci. 40: 1694-1700.

McCartney, M.G., K.E. Nestor and W.R. Harvey. 1968. Genetics
of growth and reproduction in the turkey. 2. Selection

for increased body weight and egg production. Poultry
Sci. 47: 981-990.

Merat, P. 1970. Mendelian genetics and selection for quanti-
tative traits in poultry. Results and perspectives.
WOrld Poultry Sci. J. 26: 571-586.

Merritt, E.S. 1966. Estimates by sex of genetic parameters
for body weight and skeletal dimensions in a random
bred strain of meat type fowl. Poultry Sci. 45: 118-
125.

Merritt, E.S., M. Zawalsky and S.B. Slen. 1966. Direct and
correlated responses to selection for 63-day body
weight in chickens. XIII World's Poultry Congress,
pp. 86-91.

 

101

Miller, R.H., J.E. Legates and C.C. Cockerham. 1963.
Estimation of nonadditive hereditary variance in
traits of mice. Genetics 48: 177-188.

Mode, C.J., and H.F. Robinson. 1959. PleiotrOpism and the
genetic variance and covariance. Biometrics 15:
518-537.

Meyer, S.E., W.M. Collins and W.G. Skoglund. 1962. Herit-
ability of body weight at three ages in crossbred
broiler chickens resulting from two systems of breed-
ing. Poultry Sci. 41: 1374-1382.

Mukherjee, T.K., and G.W. Friars. 1970. Heritability esti-
mates and selection responses of some growth and
reproductive traits in control and early growth

selected strains of turkeys. Poultry Sci. 49: 1215-
1222.

Nestor, K.E., M.G. McCartney, and W.R. Harvey. 1967. Genetics
of growth and reproduction in the turkey.
1. Genetic and non-genetic variation in body weight and
body measurements. Poultry Sci. 46: 1374-1384.

Newcomer, E.H. 1957. The mitotic chromosomes of the
domestic fowl. J. Heredity 48: 227-234.

Nicolaides, C. 1934. Fertility studies in poultry. Poultry
Sci. 13: 178-183.

Nordskog, A.W., and M. Festing. 1962. Selection and corre-
lated responses in the fowl. XII World's Poultry Cong.
Proc., pp. 25-29.

Nordskog, A.W., M. Festing, and M. Wehrli. 1964. Results
from a 7-year selection experiment. Poultry Sci. 43:
1347.(Abstract)

Nordskog, A.W., H.S. Tolman, D.W. Casey and C.Y. Lin. 1974.

Selection in small populations of chickens. Poultry
Sci. 53: 1188-1219.

Osborne, R. 1957. Family selection in poultry. The use of

sire and dam family averages in choosing male parents.
Proc. Roy. Soc. Edin. 66: 374-393.

Osborne, R., and W.S.B. Paterson. 1952. On the sampling
variance of heritability estimates derived from vari-
ance analysis. Proc. Roy. Soc. Edin. B 64: 456-461.

102

Parker, R.J., L.D. McGilliard and J.L. Gill. 1969. Genetic
correlation and response to selection in simulated
populations. 1. Additive Model. Theoretical and
Applied Genetics 39: 365-370.

Parker, R.J., L.D. McGilliard, and J.L. Gill. 1970a. Genetic
correlation and response to selection in simulated
populations. II. Model of complete dominance.
Theoretical and Applied Genetics 40: 106-110.

Parker, R.J., L.D. McGilliard and J.L. Gill. 1970b. Genetic
correlation and response to selection in simulated
populations. III. Correlated response to selection.
Theoretical and Applied Genetics 40: 157-162.

Parshotam, S.C., and W.A. Johnson. 1974. Intra-Sire regres-
sion of offspring on dam as a measure of the additive
genetic variance for five week body weight in Coturnix
coturnix Japonica. Poultry Sci. 53: 2070-2072.

Peeler, R.J., E.W. Glazener and W.L. Blow. 1955. The herit-
ability of broiler weight and weight and age at sexual
maturity and the genetic and environmental correlations
between these traits. Poultry Sci. 34: 420-426.

Pirchner, F., and C.M. Von Krosigk. 1973. Genetic parameters
of cross and purebred poultry. British Poultry Sci.
14: 193-202.

Rahnefeld, G.W., W.J. Boylan, R.E. Comstock, and M. Singh.
1963. Mass selection for post-weaning growth in mice.
Genetics 48: 1567-1583.

Reeve, E.C.R., and F.W. Robertson. 1953. Studies in quanti-
tative inheritance. II. Analysis of a strain of
Drosophila melanogaster selected for long wings.

J. Genetics 51: 276-316.

Richardson, R.H., K. Kojima and H.L. Lucas. 1968. An analysis
of short-term selection experiments. Heredity 23:
493-506.

Rico, M. 1964. Inheritance of quantitative characters in the
species Gallus domesticus. 1. Heritability of egg
production, egg weight and body weight. Animal Breeding.
Abs. 32: 2453.

Roberts, R.C. 1966a. The limits to artificial selection for
body weight in the mouse. 1. The limits attained in
earlier experiments. Genetical Research 8: 347-360.

103

Roberts, R.G. 1966b. The limits to artificial selection for
body weight in the mouse. II. The genetic nature of
the limits. Genetical Research 8: 361-375.

Roberts, R.G. 1967a. The limits to artificial selection for
body weight in the mouse. III. Selection from
crosses between previously selected lines. Genetical
Research 9: 73-85.

Roberts, R.C. 1967b. The limits to artificial selection for
body weight in the mouse. IV. Sources of new
genetic variance-irradiation and outcrossing.
Genetical Research 9: 87-98.

Robertson, A. 1959. The sampling variance of the genetic
correlation coefficient. Biometrics 15: 469-485.

Robertson, A. 1961. Inbreeding in artificial selection pro-
grammes. Genetical Research 2: 189-194.

Robertson, F.W. 1962. Changing the relative size of the body
parts of DrOSOphila by selection. Genetical Research
3: 169-180.

Robertson, F.W. and E.C.R. Reeve. 1952. Studies in quanti-
tative inheritance. 1. The effects of selection of
wing and thorax length in Drosophila melanogaster.
J. Genetics 50: 414-448.

Rodero, A., and R. Martinez de Miguel. 1963. Heritability of
body weight in black Castilian, Franciscan, Utrera
and White Leghorn pullets. Anim. Breeding Abs. 31:
703.

Schierman, L.W., A.W. Nordskog and R.E. Phillips. 1959.
Correlated responses in selecting for egg production,
egg size and body size. Poultry Sci. 38: 1244.
(Abstract)

Schnetzler, E.E. 1936. Inheritance of rate of growth in
Barred Plymouth Rocks. Poultry Sci. 15: 369-376.

Searle, S.R. 1965. The value of indirect selection: 1.
Mass selection, Biometrics 21: 682-707.

Sefton, A.E., and P.B. Siegel./ 1974. Inheritance of body
weight in Japanese Quail. Poultry Sci. 53: 1597-1603.

Shaklee, W.E., G.W. Knox and S.J. Marsden. 1952. Inheritance
of the sex differences of body weight in turkeys.
Poultry Sci. 31: 822-825.

104

Shimizu, H., Y. Hachinohe and H. Kawana. 1968. A study on
genetic improvement of New Hampshire chickens.

I. An investigation of selection methods. Japanese
Poultry Sci. 5: 126-130.

Shoffner, R.N., and H.J. Sloan. 1948. Heritability Studies
in the Domestic Fowl. VIII. World's Poultry Cong.
Proc., pp. 269-281.

Siegel, P.B. 1962a. Selection for body weight at eight weeks
of age. 1. Short term response and heritabilities.
Poultry Sci. 41: 954-962.

Siegel, P.B. 1962b. A double selection experiment for body
weight and breast angle at eight weeks of age in
chickens. Genetics 47: 1313-1319.

Siegel, P.B. 1963a. Selection for breast angle at eight
weeks of age. 11. Correlated responses of feathering,
body weights and reproductive characteristics.

Poultry Sci. 42: 437-449.

Siegel, P.B. 1963b. Selection for body weight at eight weeks
of age. 2. Correlated responses of feathering, body
weights and reproductive characteristics. Poultry Sci.
42: 896-905.

Siegel, P.B. 1978. Response to twenty generations of selec-
tion for body weight in chickens. XVIth World's
Poultry Cong. Proc. 1761-1768.

Siegel, P.B., and E.0. Essary. 1952. Heritabilities and
interrelationships of live measurements and eviserated
weight in broilers. Poultry Sci. 38: 530-532.

Silva, MFA., P.J. Berger and A.W. Nordskog. 1976. On esti-
mating non-additive genetic parameters in chickens.
British Poultry Sci. 17: 525-538.

Sittman, K., H. Abplanalp and R.A. Fraser. 1966. Inbreeding
depression in Japanese Quail. Genetics 54: 371-379.

Strong, C.F., Jr., K.E. Nestor and W.L. Bacon. 1978. In-
heritance of egg production, egg weight, body weight

and certain plasma constituents in coturnix. Poultry
Sci. 57: 1-9.

Swiger, L.A., W.R. Harvey, D.0. Everson, and K.E. Gregory.
1964. The variance of intraclass correlation involving
groups with one observation. Biometrics 20: 818-826.

105

Tallis, G.M. 1959. Sampling errors of genetic correlations,
coefficients calculated from.ana1ysis of variance and
covariance. Australian J. Stat. 1: 34-43.

Thomas, C.H., W.L. Blow, C.C. Cockerham and E.W. Glazener.
1958. The heritability of body weight, gain, feed
consumption, and feed conversion in broilers.
Poultry Sci. 37: 862-869.

Turner, H.N., and S.S.Y. Young. 1969. Quantitative Genetics

in Shee Breedin . Cornell UniversityPress,Ithaca,
New YorE, 332p.

Upp, G.W. 1928. Egg weight, day old chick weight and rate of
growth in Single Comb Rhode Island Red chicks.
Poultry Sci. 7: 151-155.

 

VanVleck, L.D., and G.R. Henderson. 1961. Empirical sampling
estimates of genetic correlations. Biometrics 17:
359-371.

Washburn, K.W., and P.B. Siegel. 1963. Influence of thio-
uracil on chickens selected for high and low body
weights. Poultry Sci. 42: 161-169.

Wiley, W.H. 1950. The influence of egg weight on the pre-
hatching and post-hatching growth rate in the fowl.
11. Egg weight-chick weight ratios. Poultry Sci. 29:
595-604.

wright, S. 1921. Systems of mating. Genetics 6: 111-178.

wright, S. 1931. Evolution in Mendelian Population.
Genetics 16: 97-159.

wright, S. 1935. The analysis of variance and the correlations
between relatives with respect to deviations from an
optimum. J. Genetics 30: 243-256.

Wyatt, A.J. 1954. Genetic variation and covariation in egg
production and other economic traits in chickens.
Poultry Sci. 33: 1266-1274.

Yamada, Y. 1958. Heritability and genetic correlations in
economic characters in chickens. World's Poultry Sci.
J. 15: 181-182. (Abstract)

Yamada, Y., and A.E. Bell. 1963. Selection for l3-day larval
growth in Tribolium under two nutritional levels.
Proceedings of the XI International Congress of
Genetics, The Hague, Netherlands, pp. 256-257.

106

Yamada, Y., B.B. Bohren and L.B. Crittenden. 1958. Genetics
analysis of a White Leghorn closed flock apparently
plateaued for egg production. Poultry Sci. 37: 565-
580.

Yao, T.S. 1959. Additive and dominance effects of genes in

egg production and lO-week body weight of crossbred
chickens. Poultry Sci. 38: 284-287.

Yao, T.S. 1961. Genetic variations in the progenies of the
diallel crosses of inbred lines of chicken. Poultry
Sci. 40: 1048-1059.

Yoshida, S., and W.M. Collins. 1967. Individual selection
for 4-week body weight in Japanese Quail in relation
to sex dimorphism. Poultry Sci. 46: 1341. (Abstract)

Young, S.S.Y. 1961. The use of sire's and dam's records in
animal selection. Heredity 16: 91-102.

APPENDICES

107

APPENDIX TABLE 1

Composition of the pheasant starter ration
(fed 0-6 weeks of age) in percentage

 

 

Ingredient Percent
Corn 46.35
Soybean meal, 49% 39.40
Alfalfa, 17% 3.0
Fish meal, 60% 2.5
Meat and bone meal, 50% 3.0
Whey, dried 2.0
Salt .25
Dicalcium phosphate 1.5
Limestone . 1.25
Premix (5004)a .75

 

aPremix (5004), available from Dawes.

108

APPENDIX TABLE 2

Nutrient composition of the pheasant starter ration
on calculated analysis

 

 

Nutrient Percent
Crude protein 28.00
Fat 2.61
Fiber 3.32
Calcium 1.47
Phosphorus (available) .70

M.E., Cal/kg 2730

 

109

APPENDIX TABLE 3

Composition of the pheasant grower ration
(fed 6-13 weeks of age) in percentage

 

 

Ingredient Percent
Corn 54.5
Soybean meal, 49% 25.5
Wheat middlings 7.5
Alfalfa, 17% 3.0
Fishmeal, 60% 2.5
Meat and bone meal, 50% 3.0
Salt .25
Dicalcium phosphate 1.5
Limestone T 1.5
Premix (5004)81 .75

 

aPremix (5004), available from Dawes.

110

APPENDIX TABLE 4

Nutrient composition of the pheasant grower ration
based on calculated analysis

 

 

Nutrient Percent
Crude protein 22.00
Fat 3.15
Fiber 3.64
Calcium 1.43
Phosphorus (available) .63

M.E., Cal/Kg. 2792

 

111

APPENDIX TABLE 5

Composition of the pheasant flight ration (fed
13 weeks of age until time of lighting) in percentage

 

 

Ingredient Percent
Corn 55.4
Soybean meal, 44% 14.1
Oats 10
Wheat middlings 10
Alfalfa, 14% 3.75
Meat and bone meal, 50% 3.0
Salt .25
Dicalcium phosphate 1.5
Limestone T 1.5
Premix (5004)"‘1 .5

 

aPremix (5004), available from Dawes.

112

APPENDIX TABLE 6

Nutrient composition of the pheasant flight ration
based on calculated analysis

 

 

Nutrient Percent
Crude protein 16.00
Fat 3.51
Fiber 5.30
Calcium 1.30
Phosphorus (available) .55

'M.E., Cal/Kg. 2770

 

113

APPENDIX TABLE 7

Composition of the pheasant breeder ration
(fed after time of lighting) in percentage

 

 

Ingredient Percent
Corn 53.25
Soybean meal, 44% 15
Oats 7.5
Wheat middlings 7.5
Alfalfa, 17% 3.0
Fishmeal, 60% 2.5
Meat and bone meal, 50% 3.0
Whey, dried 2.0
Salt .25
Dicalcium phosphate 1.5
Limestone 3.75
Premix (5004)3 .75

 

aPremix (5004), available from Dawes.

114

APPENDIX TABLE 8

Nutrient composition of the pheasant breeder
ration based on calculated analysis

 

 

Nutrient Percent
Crude protein 18.00
Fat 3.44
Fiber 4.65
Calcium. 2.40
Phosphorus (available) .68

M.E., Cal/Kg 2695