ABSTRACT

RATE OF PASSAGE OF INGESTED MATERIAL THROUGH
THE DIGESTIVE TRACT OF STEERS

by Charles M. Derrickson

Eight yearling Angus steers of uniform weight, age and from the

same sire were used in a series of four trials to study the effects of

 

particle size and level of intake on the rate of passage of "all-concen-
trate" rations and a concentrate plus 20% roughage ration. The treat-
ments were arranged with two steers on each in a reversal design so that
during the four trials eight observations were made on each treatment.
Inert plastic particles (specific gravity l.h25) with physical charac-
teristics similar to the feed were used as indicators to measure the
rate of passage. The effects of particle size were studied by separating
the plastic (Delrin Acetal Resin) into groups having a mean diameter of
h.76, 2.38, 1.19 and .595 mm. Within this size range the rate of passage
of inert particles through the digestive tract decreased as the size of
particles increased in diameter. There were highly significant differ-
ences in the rate of passage of all size particles at the 72, 96, and 120
hour intervals after feeding.

Comparison of rations showed a highly significant difference in
their rate of passage. The finely ground concentrate plus 20% roughage
ration passed at a significantly (P<<I0.01) faster rate than the finely

ground corn, coarse cracked corn or the finely ground ration force fed.

“'3'."

 

 

 

Charles M. Derrickson

The finely ground all concentrate ration passed through the digestive tract
of the steer significantly (P<<10.0l) faster than the coarse cracked ration.
Inert particles in the coarse cracked corn ration passed through the diges-
tive tract of the steer at a slower rate than the particles in the other
rations. These results indicate the importance of particle size on the
rate of passage of undigested residues through the digestive tract as
measured by the movement of inert plastic particles. The data suggest that
20% corn cobs in a concentrate-roughage ration stimulated some portion of
the digestive tract increasing the rate of passage of inert particles in
comparison to all concentrate rations. Comparing these results with other
experiments of mixed rations suggests that the cobs may act as a mechani-
cal stimulus increasing ruminal contractions and speeding up the passage
rate.
The results of this study showed that increasing the level of

feed intake of a finely ground all concentrate ration decreased the rate

of passage of inert particles in that ration during the 7 day collection
period. Observations on animals voluntarily consuming their allotted
ration plus 0.5% of their body weight more of the finely ground feed
showed a decrease in rate of passage. All particle sizes decreased in
rate of passage in contrast to the same ration consumed at a lower level.
However, the force fed steers showed a more rapid rate of passage than
steers consuming the same level of intake without force feeding. The
faster rate of passage of the inert particles in the concentrate plus
r°u8hlge ration in comparison to the all concentrate rations indicates

some physical and/or chemical changes take place in the digestive tract

 

 

Charles M. Derricksom

of steers on different rations.

The ration remaining in the digestive tract for the shortest

period of time showed a significant decrease in its digestibility as
compared to the ration with the longest retention time. The rate of
passage as measured by inert plastic particles was indirectly related
to digestibility.

 

 

RATE OF PASSAGE 0F INGESTED MATERIAL THROUGH

' THE DIGESTIVE TRACT OF STEERS

BY

Charles M. Derrickson

A THESIS

Submitted to
Michigan State University
in partial fulfillment of the requirements
v for the degree of

DOCTOR OF PHILOSOPHY
Department of Animal Husbandry
1965

 

 

 

 

RATE OF PASSAGE OF INGESTED MATERIAL THROUGH

THE DIGESTIVE TRACT OF STEERS

 

By

Charles M. Derrickson

fidfl w

“(Direct of Dissertation) .

 

 

 

flax: .2 7, M 65’
e fiiDate

 

 

ACKNOWLEDGMENTS

The author wishes to express his appreciation to the members
of his committee for their council and guidance throughout this study.
The committee is composed of Drs. J. A. Hoefer, D. E. Ullrey,

R. W. Luecke and E. P. Reineke.

Grateful acknowledgment is also extended to Drs. N. W. Bradley,
C. 0. Little and ward Crowe, University of Kentucky, for help in out—
lining, making facilities available, and guiding this research.

Special recognition is due the author's wife, Lena myrtle,

for assistance and encouragement during the course of this study.

11

 

 

TABLE OF CONTENTS

Chapter
I mTRODUC TION O O I I I O O O O I D O O O I C

II REVIEW OF LITERATURE. . . . . . . . . . . .
Techniques for Estimating Rate of Passage

Factors Influencing Rate of Passage . . .

Effect of particle size . . . . . .

Nature of ration. . . . . .

Frequency of feeding. . . .
Level of intake . . . . . .

Rate of Flow. . . . . . . . . . . . . . . .

III EXPERIMENTAL METHODS. . . . . . . . . . . .
Animals and their treatments. . . . . . .

Rations and methods of preparation.

Materials used as inert particles . . . .
Level of intake . . . . . . . . . . . . .
Measurement of rate of feed passage . . .
Digestibility trials. . . . . . . . . . .
IV RESULTS AND DISCUSSION. . . . . . . . . . .

V SUMMARX AND CONCLUSION. .

LITERATIIRE CITED 0 a o a a a a s e a e a e s
VITA. a e e s e a s a o a a a a a a a o s 0

APPENDIX. . . . . . . . . ...... . . .

 

- e a e a

Page

10
11

12

16
20
22
2h
26
27
hS
he
52
53

 

 

ii';

Amygqg-

 

Table

 

LIST OF lIllBLES

PRELIMINARY BATION I I I I I I I I I I I I I I I I I

 

Page

EXPERIMENTAL RATION I a I I I I I I I I I I I I I I I I I I 18

PROXIMATEANALYSISOFRATIONS. . . . . . . . . . . .

THE SCREEN SIZE AND PERCENT OF CORN REMAINING ON
EACH SCREEN. . . ..... . ......

THE NUMBER OF GRAPE AND APPROXIMATE NUMBER OF

EACH SIZE INERT PARTICLES .........

RATE OF PASSAGE OF FOUR SIZES 0F INERT PARTICLES
THROUGH THE DIGESTIVE TRACT OF STEERS

WHENFEDINFOURRATIONS
HEANDIGESTIONCOEFFICIENTS.............

iv

20

C I I 22

...h3

 

 

LIST OF FIGURES

Figure Page

1 Comparison of total recovery of fed particles
to cumulative fecal recovery. . . . . . . . . . . . . . 29

2 Rate of excretion of different size inert
particles by steers fed finely ground
concentrate ration . . . . . . . . . . . . . . . . . . 3O

3 Rate of excretion of different size particles
by steers fed coarsely cracked concentrate ration . . . 32

 

h Rate of excretion of different size inert
particles by steers force fed finely
ground concentrate ration. . . . . . . . . . . . . . . . 3h

5 Rate of excretion of inert particles through
steers fed at same level by voluntary
intake and by forced feeding . . . . . . . . . . . . . . 36

6 Rate of excretion of different size inert particles
by steers fed concentrate-roughage ration. . . . . . . . 38

Table

II

III

VI

VII

VIII

 

LIST OF APPENDICES

Page

IDENTIFICATION OF ANIMALS BY RATIONS
DURINGTHEhTRLAIS..................Sh
DIGESTIBILITY OF DRY MATTER BY INDIVIDUAL STEERS . . . . . SS
DIGESTIBILITY OF PROTEIN BY INDIVIDUAL STEERS. . . . . . . 57
DIGESTEILITY OF ENERGY BY INDIVIDUAL STEERS . . . . . . . 59

CHANGES IN BODY WEIGHT OF STEERS FED IN
METABOLISM CRATES BY 17 DAY PERIOIB. . . . . . . . . . 61

FECAL COLLECTION BY PERIODS (gms.) . . . . ........ 62
ANALYSIS OF VARIANCE OF MEAN PASSAGE RATE AT
72,96AND12OHOURS.... ........... .. 66
ANALYSIS OF VARIANCE 0F DRY MATTER DIGESTION ...... . 67
ANALYSIS OF VARIANCE OF CRUDE PROTEIN DIGESTION. . . . . . 68

vi

 

 

 

Chapter I

INTRODUCTION

The nutritive value of feeds depends upon what the animal's
digestive tract can extract from the feed and what the body can assimi-
late from the extracted portion of the feed. In order to evaluate
effectively the usefulness of any feedstuff for livestock, it has long
been realized that the incomplete availability of nutrients to the
animal should be considered. The length of time a given quantity of
feed spends in the digestive tract may be of considerable importance
in determining how much nutrient material can be absorbed by an animal.
Consequently, knowledge of the rate of feed passage through the diges-
tive tract is important, especially in digestibility studies. The in-
formation obtained in digestive studies would indicate how long a feed
could exert an influence on digestibility and would be especially use-
ful in interpretation of results when animals are changed from one
ration to another. If feeds are moved through the digestive tract at
a very rapid rate, enzymes may not have adequate time to exert their
nundnmm effect. A fast rate of movement may reduce absorption with
ILarge amounts of the nutrient material being excreted. If passage is
Blow, the animal may not pass the undigested residue fast enough and

vOluntary feed consumption could be reduced considerably.

 

 

 

 

 

 

There are conflicting opinions in the literature on the effects
of passage rate as well as a lack of definite information on the rate
of passage of different feeds through the digestive tract of ruminants.
The anatomy of the anterior part of the digestive tract of the ruminant
complicates the rate of passage of feeds through the digestive tract.
Indigestible substances have been utilized in investigating passage
rate. They have included both natural and foreign components of the

feed. Since physical characteristics exhibited by the reference sub-

 

stance influence its rate of passage through the digestive tract
(Campling and Freer, 1962 and Johnson st 31., 196k), the usefulness of
inert reference materials is restricted to the study of nutrients with
similar physical properties. When solid materials such as plastics are
fed, consideration must be taken of the fact that the bovine regurgi-
tates and remasticates a considerable portion of the food consumed;
therefore the plastic material should be of a structure that will not
be broken down during rumination. Campling and Freer (1962) have shown
that the size and specific gravity of feed particles may be factors
which influence the passage of various feedstuffs. Little considera-
tion has been given to the use of indicators which have physical
characteristics similar to those of the feed.

This study attempts to evaluate particle size, as a factor
ilmfluencing passage by using an indicator which possesses many of the
F*wsical properties of feeds. The material should possess the follow-
ing characteristics to be used as reference substance. The material

mmst be inert, indigestible and recovery from the feces must be

 

 

possilile. Therefore it is necessary to feed substances which the animal
will not digest nor absorb and which do not affect the digestive system.
The material should possess characteristics that would permit it to be

ground into particle sizes similar to those of the feed.

 

 

 

 

 

Chapter II
REVIEW OF LITERATURE

It has been generally assumed that an increased rate of feed
passage is accompanied by an increased voluntary feed intake and a lower
digestibility. It was concluded by Blaxter st 31. (1956) that the method

of preparation modified the rate of feed passage through the gut and this

 

rate was the determinant of its digestibility. Wright (1929) suggested
that changes in the rate of feed passage influenced voluntary intake.
Blaxter 33 21. (1956) and Crampton (1957) stressed the importance of the
rate of disappearance of digesta from the reticulo-rumen in determining
the voluntary intake of roughage. Ewing and Smith (1917) reported that,
in general, more complete digestion of total dry matter was associated
with more rapid passage of feed residue through the ruminant while crude
fiber digestibility decreased. Blaxter gt :1. (1956) found that increas-
ing the feeding level resulted in an increase in the passage of food and

a fall in its digestibility.
Techniques for Estimating Rate of Passage

Various techniques have been employed in studying the rate of
passage of feed through the digestive system of the ruminant. From
these techniques have come several different terms used to indicate the

rate of movement of digesta. Balch (1961) defines "rate of passage" as

h

 

 

the tinae taken by undigested residues from a given meal to pass through
the digestive tract or through some part of the digestive tract. This is
distinctly different from the "flow of digests" which is expressed as the
rate at which the mixture of undigested residues from a previous meal
passes a given point in the digestive tract. These terms are nearly
synonymous when referring to the lower tract of the ruminant; but anterior
to the reticulo-omasal orifice, mixing and sifting of rumen contents
occurs to such an extent that digests flowing past any one point at any

one time contains residues from several meals.

 

The "mean retention time", defined as the mean length of time food
stays in the digestive tract, was obtained by Blaxter gt :1. (1956) by
dividing the sum of the times which individual stained dried grass parti-
cles spent in the tract by the total number of particles. Castle (1956)
measured the "mean retention time" by adding together the times of excre-
tion from 5 to 95% at intervals of 107. and then dividing by 10. This
value termed "R" represented the mean retention time in hours of stained
hay, was calculated from percentage excretion curves and was used as a
measure of rate of passage.

The most widely accepted technique of measuring rate of passage
is the one based on the method of Balch (1950). It involves counting the
number of previously stained feed particles appearing in the feces in
successive intervals of time. Blaxter st 21. (1956) using nature sheep
and Balch (1950) using mature cattle estimated the effect of grinding on
the passage rate of stained hays. The investigations of rate of passage

With goats by Castle (1956) have included use of stained oats, straw, hay

 

 

 

and fecal fibers .

The conventional method of measuring rate of passage by using non-
feed markers ingested as a loose mixture with feed has not generally been
accepted as satisfactory since the markers have a tendency to become
separated from the food with which they were originally fed. Many such
substances have been used in studying the rate of passage of feeds through
the digestive system. Hoelzel (1930) used rubber, cotton threads, seeds,
glass beads and several metals. Mbore and Winter (1930) used ferric oxide
and rubber. Campling and Freer (1962) investigated the passage of inert
particles through the cow using rubber and several plastics.

The early work of Ewing and Smith (1917) estimated the rate of
feed passage through steers using rubber markers and moisture content of
feces. They assumed that a higher moisture content of feces was indica-
tive of a rapid rate of passage; however, no actual determination of the
time taken by food to pass through the gut was made. These workers also
used digestion trials followed by slaughter and examination of the diges-
tive tract contents. King and Moore (1957) used inert plastic materials
of different size and density along with powdered chronic oxide to study
passage rate and Johnson 2E.2l3(196h) used chronic oxide incorporated as
a component of paper and as a powder. Brandt and Thacker (1958) studied
the passage of radio-active chronic oxide and'Wcller gt :1. (1962) com-
pared the passage ef lignin and polyethylene glycol.

Indices of the rate of passage have been developed by several
workers (Balch, 1950; Blaxter gt 21., 1956; Castle, 1956; and Brandt and

Thacker, 1958). In a rather extensive study of feed passage through the

 

 

   

 

7

cow, Balch (1950) used a 5% excretion time and an 80% minus 5% as des-
criptive of his accumulation curves. Balch has shown that the time taken
to excrete 5% of the stained residues of a meal is approximately equiva-
lent to the time required for the feed to pass through the omasum, abomasum
and intestine. He further proposed that the 80% minus 5% excretion time
was the interval between excretion of 5% and 80% of the stained particles
and was indicative of the time the feed particles spent in the reticulo-
rumen. Brandt and Thacker (1958) introduced the terms t2 and t1 to repre-
sent the time spent by the feed in the reticulo-rumen and the remainder of
the tract, respectively.

Castle (1956) calculated a term "R" which was defined as the mean
retention time in hours which stained hay particles spent in the diges-
tive tract. This term was calculated by adding together the times of
excretion from 5% to 95% at intervals of 10%, taken from graphs plotted
on rates of excretion of undigested residues of stained hay, and dividing
the sum.by 10. This value was used as a measure of the mean retention
time in hours, of the stained particles in the alimentary tract.

Another term.used in describing rate of passage time is referred
to as "mean time" (Blaxter gt £1., 1956). Mean time is a measure of the
mean length of time food stays in the digestive tract and is determined
by dividing the sum of time which individual stained particles spend in
the digestive tract by the total number of stained particles excreted.

After using stained particle counts to calculate the rate of
passage by each of the above mentioned methods Shellcnberger and Keslor

(1961) concluded that all methods discussed appeared satisfactory, but

 

 

 

thOBe methods appeared to be slightly more reliable which measured mean

time spent in the digestive tract by each stained particle.

Factors Influencing Rate of Passage

Effect of particle size

 

There is considerable evidence which suggests that, with diets
containing normal levels of roughage, small particles are eliminated more
rapidly than large ones. Ewing and Smith (1917), using rubber markers,
concluded that finer particles of feeds and finer ground feeds passed
through the ruminant animal more rapidly than coarser feeds and that
coarse feeds and roughages retarded the rate of passage of feed residues.
Blaxter 22.21' (1956) concluded, after feeding sheep dried grass in its
natural form and in the form of cubes made from.medium.groundand finely
ground material, that the method of preparation modified the rate of
passage. The finely ground, cubed grass passed through the digestive
tract more rapidly than the long, dried grass. Castle (1956b), using
stained hay and stained fecal fragments as markers, reported that the
small fecal fragments invariably traveled faster than the hay and sug-
gested that the increased rate of passage was due mainly to the smaller
particle size. Rodrigue and Allen (1960), comparing the rate of passage
of ungroumd hay with hay ground to different degrees of fineness ob-
served a more rapid passage of finely ground hay throughout the entire
tract. These workers concluded that the finer the grind the faster
the rate of passage.

These observations are in agreement with Ewing and Smith (1917),

 

 

 

Blaxter e_t a_l. (1956) and Meyer e_t 21. (1959). Ewing and Smith (1917)

conclnided that finer particles of feeds and finer ground feeds passed
through the ruminant animal more rapidly than coarse feeds and that
coarse feeds and roughages retarded the rate of passage of feed residues.
Blaxter 3t :1. (1956) concluded from feeding sheep dried grass in its
long form and cubes made from medium ground and finely ground material,
that the method of preparation modified the rate of passage. The finely
ground, cubed grass passed through the digestive tract more rapidly

than the long dried grass. Meyer 33 21. (1959) reported that ground
pelleted hay passed through the digestive tract of sheep at a faster
rate than unground hay. The fact that finely ground, cubed grass and
hay passed through the digestive tract more quickly than long material
is contrary to the results of Balch (1950) and Balch gt 21. (195k, 1955)
who reported that ground hay in rations in which all the hay was ground
was excreted over a longer period than hay in a similar ration in which
the hay was not ground. Meyer gt :1. (1959) postulated that the increased
feed intake of sheep which resulted when hay was ground and pelleted was
the direct result of a faster rate of digestion in the reticulo-rumen.
This accelerated digestion of the finer hay particles allowed a faster
rate of passage of feed through the digestive tract. The pelleted
ground roughage passed more rapidly through the digestive tract by vir-
tue of a faster movement from the reticulo-rumen (Blaxter and Graham,
1956; Blaxter e_t_ a_1., 1956; and Meyer e_t 3;” 1959). Balch (1950) noted
that ground hay given as a small addition to unground hay was excreted

more rapidly than the unground hay. Stained hay particles were used to

 

 

10

measure the rate of passage of undigested residue.

King and Moore (1957), using inert plastic particles, reported
that particles of 1.2 specific gravity passed at a faster rate than either
lighter or heavier particles. The size particles of 1.2 specific gravity
which passed most rapidly were between 20 and 30 cu. mm. Campling and
Freer (1962) reported the mean retention time of inert particles of speci-
fic gravity 1.2 to be directly related to the size of the particle within
the range of 17-58 cu. mm. The larger particles were retained 12% longer
than the smaller.

Balch (1950) reported that the roughage in diets in which all the
hay was ground required considerably longer periods of time to pass through
the digestive tract than similar hay diets in which the hay was not ground.
Hoelzel (1930), using several species of non-ruminants, found the rate of
passage nearly proportional to the specific gravity of the materials used.
King and Moore (1957), using Cr203, suggested that factors other than den-
sity and particle size apparently influenced the rate of passage. Cr203
(with a specific gravity of 5.1 and very finely dispersed) would be ex-
pected to move very slowly through the digestive tract; however, on the
basis of comparison with plastic particles the Cr203 moved faster than
predicted. Moore and Winger (l93h) found considerable variation in the

. rate of passage of rubber rings and ferric oxide.

Nature of ration
Some of the early work on rate of passage in ruminants (Ewing and
Smith, 1917) reported that the two most important factors determining the

rate of passage were the nature of the ration and the level of feed intake.

 

CO]

for
his
dai
Ker

Isl;

We 1

 

 

 

11

Bileh e_t fl' (1956) noted very slow passage of a ration containing much
concentrate and little roughage. The roughage remained for an abnor-
mally long time in the reticulo-rumen. Castle (1956) noted greater
retention time for straw than for hay when both were fed together. Bell
(1960) reported that roughages such as wheat straw and alfalfa hay which
were least capable of swelling in water passed through the non-ruminant
digestive tract at a slower rate than other "bulks" such as bran, cellu-
lose or corn cobs. Blaxter gt :1. (1961) feeding poor, medium and good
quality roughages to sheep found the poorest quality to pass through the
gut more slowly than the medium quality roughage which, in turn, passed

through the gut more slowly than the highest quality roughage.

Frequency of feeding

As previously cited, Ewing and Smith (1917) suggested that the
rate of passage of feed residue was influenced by the quantity of ration
consumed. They reasoned that an increase in consumption would cause an
increase in the rate of passage of feed residues. Rakes st 21. (1957)
found no differences in the rate of passage of the same total daily in-
take of a medium quality chOpped alfalfa-orchard grass hay when fed twice
daily or ten times daily to dairy heifers. Campling 32 31. (1961) sug-
gested that the voluntary intake of a roughage by a cow is closely

nelated to the mean retention time in the digestive tract.

ngel of intake
The level of feed intake appears to have a direct effect on the

rate of passage of feed residue through the digestive tract. The work

 

 

 

12

of Campling gt 31. (1961) indicating a decreased retention time with
increasing intake is in agreement with the results of Balch (1950) and
Blaxter st 21. (1956). Blaxter st 31. (1956) found that increasing
the level of feeding resulted in an increase in the rate of passage of
feed and a decrease in its digestibility. These workers concluded that
the method of preparation modified the rate of passage of feed through
the digestive tract and this rate was the determinant of its digestibi-
lity. Castle (1956) reported the mean retention time to be directly
related to the daily intake of feeds. As the feed intake increased the
mean retention time ("R") decreased. Shellenberger and Kesler (1961)
reported the rate of passage of feed residues to be faster in high
producing cows consuming greater quantities of feed than low producing
cows. These researchers found the level of dry matter intake was

correlated with the rate of passage.

Rate of Flow

The flow of digesta along the digestive tract has been measured
by using surgical preparations in which the flow of digesta was perma-
nently exteriorized by means of re-entrant fistulas.

Harris and Phillipson (1962) and Hogan and Phillipson (1960)
measured the flow of digesta into the duodenum.by collecting digesta
from the proximal cannula, measuring and sampling and returning the
digesta through the distal cannula. Singleton (1961) measured the flow
of digesta into the duodenum by an electromagnetic method on an unopened

tube connecting the two cannulas through permanently exteriorized duo-

 

 

 

KN
tra
Him
face

duod‘

 

 

l3

denal loops. Results of this work clearly showed the flow of digesta
into the duodenum to be phasic with variations both in size and frequency
of the gushes which were followed by varying amounts of backflow.
Phillipson (l9h8) noted that digesta in the ruminant flowed in gushes
every few minutes into the duodenum. The work of Phillipson (1952)
showed that the flow of digesta passed to the duodenum in gushes at
regular intervals for 17 out of 2h hours and that the flow was more regu-
lar during rumination. This work suggested that the flow of digesta from

the abomosal cannula was accelerated during eating. Measurements taken

 

by Hogan and Phillipson (1960) indicated the mean rate of flow to be 360
and 180 ml. per hour in the duodenum and ileum, respectively. Phillips
and Dyck (l96h) measured the flow of digesta into the duodenum of sheep
by continuously infusing an indicator solution of polyethylene glycol
h000 at a constant rate into the abomasum via a cannula. The volume of
digesta flowing was calculated from the dilution of the indicator in
samples of digesta obtained from a duodenal cannula.

Balch (1950) introduced a suspension of ground stained hay into
the abomasum of cows and found that the time at which 93 - 97% of the
marker was excreted was the same as the time required for 5% excretion
of the marker given by mouth. Castle (1956c) found stained fecal
fragments that had bebn introduced directly into the duodenum of the
goat appeared in the feces 9 to 12 hours later with a maximum concen-
tration occurring in the feces 1 to 2 hours after their first appearance.
Ninety-five percent of these particles fed by mouth appeared in the
feces 1 to h hours after the appearance of the particles placed in the

duodenum.

 

tn

the

the.

int

Peric

 

 

 

Chapter III

EXPERIMENTAL METHODS

0

Animals and their treatments .
Fourteen yearling Angus steers were used in a series of four r-fia

trials. They were selected from one herd and had all previously been

treated similarly. The steers were from the same sire and were of

uniform weight and age.

 

The steers were placed in individual box stalls and fed a uni-
form ration for a 60 day adjustment period. The ingredients used in
the ration fed during the adjustment period are given in table 1. The
shelled corn was finely ground in a hammer mill and mixed with the other
ingredients in a conventional feed mixer. The high concentrate ration
consisting mainly of ground shelled corn was supplemented with protein,
minerals and vitamins. All ingredients were mixed for at least 20
minutes. The steers were given only a small amount of the ration in
the beginning of the adjustment period and gradually increased until
they were receiving all they would conswme each day. If a steer did
not consume his daily ration it was cut back until the allotted amount
was consumed. Steers were given free access to water while they were
‘in the box stalls. The level of water intake of the steers for the
experimental period was determined during the part of the preliminary'

periods in which the animals were kept in stanchions.

1h

 

tht

   

 

15

TABLE I. PRELIMINARY RATION

 

7"

 

 

Ingredients % of ration Pounds per ton
Ground shelled corn 83.55 1,671
Soybean meal 15.00 300
Mineralized salt 0.50 10
Ground limestone 0.50 10
Steamed bone meal 0.h0 8
Vitamin A &.D premix* 0.05 1

Total 100.00 2,000

 

*Each gram of the vitamin A & D premix supplied 10,000 I.U. of

vitamin A palmitate and 1,250 I.U. of vitamin D2.

The stalls were bedded with tdbacco stems to discourage the con-
sumption of the bedding. During the last part of this preliminary period

the steers were placed in stanchions for two 10 day periods. After re-

maining in the stanchions for 10 days the steers were returned to their

 

box stalls for a rest period. They were allowed to remain in the stalls
five days before returning to the stanchions. The conditioning period
was conducted to accustom the steers to confinement. Final selection of
the eight steers used in this study was based on the following conditions:
(a) Rapid adjustment to the confined conditions and
maintenance of uniform feed consumption.

(b) No signs of swelling in their legs and joints while

 

   

 

16

 

remaining in.the stanchions for extended periods. The eight steers were
paired according to weight and placed in stanchion type collection crates
for the 68 day feed passage and digestion experiment. The animals re-
mained in the crates throughout the entire experiment except to be taken
out at the end of each trial at which time they were weighed and returned
to the crates. Each pair of steers was arranged in a reversal type arrange-
ment so that during the four trials eight Observations were made on each
treatment.

Two steers were placed on each of the four rations with the daily
allowance determined by the steer consuming the smallest amount of feed
during the preliminary period. The feed offered and that left uneaten
was weighed daily until the steers were on a constant level of intake.
The steers were fed twice daily at 12 hour intervals. One-half of the
daily ration was fed at 6 A.Mh and the other one-half was fed at 6 PgM.
The steers were watered twice daily, just prior to the morning and
evening feeding. The level of water intake was held constant throughout
the four feeding trials. The animals were offered two gallons of water
before each feeding. The level of water intake determined during the
preliminary period did not appear to affect the dry matter intake. The
two steers on each of the four trials receiving the higher level of
feed intake were given the same amount of water as the animals on the

lower level of feed intake.

Rations and methods of preparation
The rations required for all four trials were ground and mixed

at the same time with food ingredients from.the same source. The corn

 

 

   

 

l7

 

in ration l and 3 and the corn and cube in ration h were finely ground
in a hammer mill. The corn in ration 2 was coarsely cracked with a burr
mill. The remaining ration ingredients were not altered from their
usual form.

One ton each of the four rations was mixed at the'beginning of
the experimental period. The rations were mixed in 1,000 pound lots in
a 1,500 pound commercial feed mixer. The minerals and vitamins were
premixed before adding to the corn and protein mixture. Each batch of
the experimental ration was mixed for a period of thirty minutes.

During each trial two steers were fed (ration l) finely ground
shelled corn as the basal ration; two steers were fed (ration 2) the
coarsely cracked corn; two steers were given (ration 3) the finely
ground corn ration and force fed at the rate of 0.5% of the animals
live weight above the basal ration; and two steers were fed (ration h)
finely ground corn plus 20% ground cobs. All four of the rations were
supplemented with protein, minerals and vitamins A and D. The daily ra-
tion contained a total of 22,680 I.U. of vitamin A palmitate and 2,835
I.U. of supplemental vitamin D2. The composition of each of the four
rations is given in table 2. Rations l, 2 and 3 were all concentrate
rations of identical composition, they differed in particle size and

method of administration.

 

 

 

 

 

 

 

 

18

TKBLE 2. EXEERIMENTAL RATIONS

 

 

 

Rations-pounds per ton

 

 

Ingredients ' '1, 2 and 3 h
Ground shelled corn 1,686 - 1,286
Soybean meal (hh% C.P.) 275 275
Ground corn cobs . --- I ' KOO
Trace mineralized salt 20 20
Ground limestone 10 10
Steamed bone meal 8 8
Vitamin A & D premix* 1 1
Total 2,000 2,000

 

fl

*Each gram.of the vitamin.A & D premix furnished 10,000 I.U. of

vitamin A palmitate and 1,250 I.U. of vitamin D2

Proximate analyses of the experimental nations are given in
table 3. In preparing the feed for analysis samples were taken each
day during the experimental periods. The composite sample was mixed
well at the end of each trial and an aliquot taken for analysis. The
sample was ground_in a'Wiley mill, mixed and stored in an air tight
container until analyzed. The rations were analyzed according to
standard methods (A.0.A.C.,l960). Crude fiber determinations were
not made; however, average cellulose percentages are listed for the

four trials.

 

 

 

   

19

TABLE 3. PRDXIMATE ANALYSIS OF RATIONSI

 

 

 

 

Ration
Component 1 2 3 h
Moisture (S) 12 . 37 11. 95 12. 37 11. 79 F]
Crude protein (i) 13.63 1h.56 13.63 13.22 m:
Cellulose (%) 6.26 6.8h 6.26 11.33 F
Gross energy (kcal./g) 3.881 3.831 3.881 3.860 r J

 

 

1Analysis made by the fientucky Agricultural Experiment

Station Animal Nutrition Laboratory.

Since attempts were made to study the rate of passage of corn, the
fineness of grind of the corn was measured. Representative samples of
ground corn were taken from the mixer after the corn was well mixed. The
remainder of the ration ingredients were added to the corn and mixed for
30 minutes in a commercial feed mixer. The particle size or degree of
fineness was established from the percentage of a 250 gram sample of the
ground corn remaining on each of six screens (h, 8, 16, 30, SO, and 100
mesh) after the sample was shaken for five minutes on a mechanical shaker.
The particle size was established from the average of five 250 gram sam-
ples taken from each mixture of cracked and fine ground corn. Therefore,
the fineness of grind, as determined by the above method, is a measure
of the particles remaining on each of the screens. The percent of ground

corn remaining on each screen, taken as the average of five samples is

 

   

20

given in table 1;. The majority of particles in the finely ground feed
were 2.38 mm and smaller while the majority of the particles in the

cracked corn were 2.38 mm and larger.

TABLE h. THE SCREEN SIZE AND PERCENT OF CORN REMAINING ON EACH SCREEN

 

 

% of material on each screen

 

 

 

 

Screen mesh Diameter of opening (mm) Fine grind Cracked
b 11.76 1.5 25.7
8 2.38 22.5 61.8
16 1.19 36.5 7.9
30 .595 21.5 2.7
50 .297 17.0 1.3
100 .1h9 1.0 .6

 

Material used as inertparticles

The inert plastic material used in this study to measure the
rate of passage of feeds through the digestive tract was based on the
same percentage of fineness as the ground corn. A 250 gram sample of
the ground plastic was placed in the number h mesh screen and shaken
for five minutes on the mechanical shaker. Particle size was then
separated according to the diameter of the opening of the screens as
shown in table h.

The material used as inert particles was Delrin Acetal Resin

‘1

av

 

 

21

(E. I. du an , Wilmington 98, Del.). This material was selected for use
because of its hardness, its grinding properties, which allowed it to be
separated into sizes similar to ground corn, and its specific gravity
(1.h2S) which is similar to that of ground corn. Since it has been shown
that the physical characteristics of a feed determine to a large extent
its passage rate, it appears logical that the inert material should
possess as near as possible the physical characteristics of the feed.

The specific gravity of both the ground corn and plastic was
determined with a Beckman Medal 930 air compressed pycnometer. Since the
specific gravity of the plastic was similar when measured with this in-
strument to the specific gravity given by the manufacturer it was assumed_
that measurements made were reasonably accurate. The pycnometer measures
the volume of powder, granular, porous or solid materials. Therefore the
specific gravity of a sample, which is the ratio of the sample density to
water at hOC, is readily computed since the pycnometer provides a method
for volume measurement. To further check the reliability of the air com-
pressed pycnometer the specific gravity of ground corn was calculated by
first weighing the substance in the air and then weighing it under water.
The values obtained by this method were similar to those given by the
pyonometer.

The plastic which was obtained in 1/2".x 5' plastic rods was
ground in the same hammer mill, through the same screen as was the corn.
The ground plastic was separated into particle sizes, and ratio of
sizes fed was based on the percentage of the respective size particles

of corn as determined by separating through the different size screens.

 

TV

 

22

The particle size and quantity of the inert material fed is given in

table 5.

TABLE 5. THE NUMBER OF GRAMB AND APPROXIMATE NUMBER OF EACH SIZE
INERT PARTICLES

 

 

 

 

 

Amount fed (gms) Approx. no. particles fed
Screen opening Fine grind Cracked Fine grind Cracked
b.76 3.h 58.6 118 282
2.38 51.3 1uo.8 1,938 5,068
1.19 83.2 18.0 30,916 6,h26
.595 h9.0 6.2 ' 105,052 16,625
.297 38.8 3.0 --- —--
.1h9 2.3 1.h ——- ---

 

Level of intake

 

 

The animals were fed at two levels of intake. During a prelimi-
nary period all steers were fed free choice, to determine the daily intake
of full feeding as near as possible. The level of feed intake was deter-
mined by the steer consuming the smaller amount during this period. The
daily allowance was set at h560 grams with 2280 grams being fed at 6 A.M.
and 6 P.M. daily. Two of the eight steers were force fed in each trial.
The term "forced feeding" in this experiment is used to describe the
method of feeding animals more than they would voluntarily consume. Two

animals on each trial were fed 0.5% of their body weight more feed daily

 

 

23

than the intake level of the other steers. For example, steers weighing
600 pounds would receive an additional 3 pounds of feed daily or a total
of 13 pounds of feed. The animals receiving the extra allowance were
first offered their feed in metal feed boxes attached to the metabolism
crates. The steers were not force fed unless they refused to consume
their ration within a thirty minute period. The amount of feed remaining
at the end of one half hour was mixed into a slurry and again offered to
the animal. The portion of the feed not consumed by the animal was then
force fed by using a plunger type gun which would hold approximately 6
pounds of the finely ground feed made into a slurry. To force feed an
animal its head was elevated with the nipple like extension of the gun
placed over the back part of the tongue. The slurry was then slowly
forced into the animal's month. Most of the animals swallowed the feed
with very little resistance after the first few feedings. The feed was
made into a slurry by mixing with the 2 gallon portion of water allotted
to the animal at each feeding. Although the steers were offered their
feed in the dry and wet form, it was necessary to force feed a portion
of their ration with the gun after two or three days of feeding. It was
necessary to force the ration down six of the eight steers on the force
fed ration. Once the animal failed to consume his total ration, it was
usually necessary to force feed the entire ration throughout the
remainder of the trial.

The force feeding mechanism was a simple plunger type gun made
of 16 gauge stainless steel. The feeder was h inches in diameter and

15 inches long. It was designed so the feed and water mixture could be

 

 

2h

poured in from.the plunger end. The opposite end had a h inch bevel
which reduced it to 1 inch in diameter. The inch diameter was extended

to a length of 6 inches for placing on the back of the animal's tongue.

Hbasurement of rate of feed passage

The measurement of the rate of feed passage through the digestive
tract was a modification of the method of Balch (1950). At a single
feeding the steers were given a small amount of stained corn and colored
plastic particles so undigested particles could be identified visually
in the feces. Brilliant green stain (Fisher certified) was used in con-
centrations of one gram per liter of water. The grain was colored by
steeping for six hours in a hot solution of the stain then thoroughly
washed with cold water and dried.

0n the morning of the 11th day of the experimental period 5.0%
of the daily intake of dry matter was fed as stained corn and 5.0% sub-
stituted with the plastic particles. The plastic particles and the
stained grain were mixed with a portion of the normal diet before being
offered to the animals. In order to get the steers to consume the mixture
it was moistened with a portion of the water allotted to the steer. The
feed and marker mixtures were very rapidly consumed when made into a
slurry. The animals were allowed one-half hour to eat the allotted feed
with the midpoint in this half hour taken as the time of feeding. A11
steers consumed their feed in the allotted time.

The collection of feces began 12 hours after feeding the

indicators and continued at 6 hour intervals for the first 72 hours of

 

25

the collection period and at 12 hour intervals for the following 96 hours.
At each time of sampling the accumulated feces were weighed, thoroughly
mixed and sampled. A ZOO-gram sample was taken for plastic and stained
particle counts. Additional portions of 10% of the total collection for
each period were taken for dry matter determinations, the dried material
being retained for the analyses connected with digestibility trials. The
fecal samples were stored at -l7°C. in polyethylene freezer bags until
they were prepared for analysis.

For the plastic and stained particle count two SO-gram aliquots
of feces were taken and washed through sieves that had previously been
used to separate the plastic particles into different sizes. The fecal
material was placed on the h mesh screen and each particle size washed
over to its respective screen by placing under a stream of water. After
thoroughly washing the sample over each screen, the plastic particles
and the stained corn particles were counted and recorded. Particles
were retained on the h, 8, l6 and 30 mesh screens with none being found
on the 50 screen. Total plastic particles on each screen were counted
when the total did not exceed 100. ‘When the count exceeded 100, the
feed residue and particles retained on a screen were washed from the
screen onto a 12.5 cm filter paper in a suction funnel. The materials
were evenly distributed on the filter paper by shaking and rotating the
funnel and then pulling the water into the suction flask. A hardware
cloth with 1/2 inch square Openings was placed over the filter paper
and particles from 10 of the 76 squares were counted. The number of

those particles of different sizes for each individual sampling period

 

 

 

26

was then calculated and the recovery for each period was expressed as a

percentage of the total number of the respective size particles fed.

Digestibility trials

 

Determination of digestibility of dry matter, crude protein and
gross energy was made from the composited fecal samples for each of the
7 day collection periods and results are given in appendix tables II,
III and IV. During the collection periods the feces were collected on
plastic sheets in metal pans placed behind the steer. The 20 samples
collected from each steer during each trial were composited and an
aliquot was taken and stored for chemical analysis. During the experi—
mental periods the feeds were sampled daily. The feces were dried in a
forced-draft oven at 65°C. to a constant weight and then allowed to
equilibrate with the atmospheric moisture. The samples of feed and
feces were then ground in a Wiley mill through a medium-fine screen.
After the samples were ground, each was mixed and stored in an air
tight sample bottle. Rations and feces were analyzed according to
standard methods (A.0.A.C., 1960). The digestion data were analyzed
by the analysis of variance technique (Snedecor, 1956) and significance
of individual differences determined by Duncan's Multiple Range Test
(Duncan, 1955).

 

Chapter IV

RESULTS AND DISCUSSION

The term "rate of passage" has been used in this study to denote
the time taken by inert particles after feeding to pass through the
digestive tract of the steer. Since corn made up 6h.3% of ration h and
814.3% of ration 1, 2 and 3 it was used as the basis in determining the
material selected for studying the rate of passage in this study.

The cumulative percent excretion of the inert particles is shown
on figures 2-6. Each curve represents the mean values of observations
on eight steers. The cumulative percent excretion was used in order to
calculate the rate of feed passage by various methods as R, 5% and 80%
minus 5% values. These methods are explained on pages 6 and 7 of the
review of literature. R refers to the mean retention time as determined
by Castle (1956a). The 5% value as the rate of passage through the
omasum, abomasum and intestines and the 80% mdnus 5% as the rate of
passage through the rumen and reticulum as determined by Balch (1950).
Since a 95% recovery is required for calculation of R and the recovery
rate in this study'was below 95% in.most cases, calculations could not
be made on the percent recovery of the total number of particles fed.
However, the excretion curves calculated on the percent of inert particles
fed appear to follow the same general pattern as those calculated on the
percent of the total particles excreted in the feces. This can be ob-

served in figure 1. These two curves represent data obtained with the

27

 

28

finely ground corn ration l.

The recovery of undigested particles of stained corn when wash-
ing samples over the screens was insufficient to calculate passage rate.
The stained corn was digested or broken into particles less than .595 mm
which would not have been retained on the screens or it may be possible
that the dye was extracted from the grain during digestion. However, the
stained feed particles recovered had retained a sufficient amount of
their artificial coloration to differentiate them from regular feed par-
ticles. No attempts were made to calculate curves from the few particles
that were recovered.

These data show that the rate of passage of inert particles
through the digestive tract of the steer is significantly affected by
the nature of the ration and the size of particles fed. Statistical
analyses show ration composition and particle size have a highly signifi-
cant (P«<:.Ol) effect, whereas the rate of passage between animals ap-
proached significance only at the 10% level. Figure 2 illustrates the
cumulative percent excretion of inert particles for the finely ground
concentrate ration 1. These excretion curves show that the finer parti-
cles represented in the top curve with a mean diameter of .595 II in
size, were excreted more rapidly'(fh<:.01) than the larger particles
shown in the lower curves. Others have made similar observations and
attempted to explain the faster movement of smaller particles. Shalk
and.Amadon (1928) suggested that small particles of ground hay moved
rapidly out of the rumen because they would absorb water faster than

the large particles. These workers further theorized that the digesta

 

 

A9305 3.3.3an amen.“ mmavoom means as;

 

 

«in a: a: 62 , a m1. me "a -
- p p p . \o\ 0
caused \.\\.. r
m as Robeson Hence .uIII. \.\ .\ OH
.\\ .\
\ \ f
venomous a no bo>ooem . .\x. .\ om
\ .\
\
.\. .\ .om
\ \
a\ Q
.\ \ .3
x .\ x
\ . dm
8 x \ \ . \.\
\. .
.\ \ S
\ \ \ \ o
a\\ \e e\ 6N
\ \.\ \ \ .\ \
.\ \s O@
.\. om
.\
o\ f
\ OH

Shampoos.” Haoom $33258 op 333me com Ho @9682 Hence mo nominees .H omsmfim

 

pensioxe setornied niau; go 98s3ueoled annsInmng

 

 

30

AF.

«ma

€305,333an when.“ ”nausea menus and.
QWH 44H DNA 0% NF m: 4N

p P

a. \
#\\\.\
x \. \x
_\

J—
p
b

 

2.4. x

 

as mmé xulllx \ .\
E and . . \.\\\
same. 7'... \\ \
omen eaoapnam \. xxx

$\\ \\

a .53.: openness-o0 meson»
Human pom shoe...» .3 3.3.“me when.“ on: amonomnwv mo compose: mo 3mm .m shaman

dd'
scans-5.23:9.
paaazoxe setotazsd amen; go efisaueoled antistnmng

d
O\

 

.8.

 

31

in the reticulo-rumen separated into two layers and as the particles of
digesta became saturated and partly decomposed the specific gravity of
the particles increased and the particles tended to sink into the ven-
tral region of the reticulo-rumen, thus increasing their chance of pass-
age to the omasum and abomasum. Balch (1950) suggested that the differ-
ence in passage rate of feeds with different particle size was due to a
more rapid removal of fine particles from the reticulo-rumen. After
studying the size of particles in the digesta at the reticulo-omasal
orifice and in the feces, Balch suggested that either sifting of large
food particles occurred at the orifice or the particle size was reduced
at a later site in the digestive tract. The explanation presented would
fit the present data, which suggest that the larger particles remain for
a longer period in the reticulo—rumen until reduced to smaller sizes.
The percent recovery of the large particles (b.76 mm) to small particles
(.595 mm) during the 120 hour period for ration l was 60, 70, 76 and 80%
respectively. Only 22 hours were required for excretion of 5% of the
smallest (.595 mm) particles, whereas 3h hours were required for excre-
tion of 5% of the large (h.76 mm) particles.

The results Obtained with inert particles in a ration consisting
of coarsely cracked corn (ration 2) are shown by the cumulative percent
excretion of inert particles in figure 3. The excretion for the first
2h-h8 hours was slow; however, after h8 hours it increased with a con-
stant and continuous curve.

The percent recovery of inert particles at the end of 120 hours

was much lower than was found in ration l, the recovery being 56, 62,

 

 

A9305 uoaoapna Eon.“ weaves.“ seems as;

 

   
 

 

an a: a: 02 em 2. me a...
. . . . . . \xlnnhwt- o
\»\.\ \.\
05.: .mlllla \\\\m¥\\\\\ 0H
mm . m xi I Ix \\
main ..|.|..|. \+\\ . \ UN
mmm. e.|l.|le \o \\\
\
omen eaoapnam \.\ on
\
as
am
fl
3
we
om
om
OOH

 

dogma evanescence coxomno
haounaoo emu mucous he. noacaemem £95” and. 98.333 Ho sowponouo we open .M 9:83

pSJBJOXB SQIOIJJBd amen; go eBenueoJed BAIJEInan

   

33

 

611 and 68 percent for the large to smaller particles. These results
further suggest that larger particles remain in the digestive tract for
a longer period of time than the finer particles. Whether this was due
to some screening of large particles at the reticulo-rumen orifice as
suggested by Balch (1950) was not determined. The slower rate of passage
of the inert particles in this ration was apparently due to the higher
percent of large particles fed in relation to those of smaller size. The
smallest particles (.595 mm) fed in this ration passed through the di-
gestive tract at a more rapid rate than the larger particles. This is in
agreement with the results of others (Balch, 1950; Balch gt_al., 195h;
Blaxter gt 21. 1956; and Castle, 1956) who reported small amounts of
ground hay in mixed diets passed at a faster rate than the long hay in
the ration. Although the smaller particles were excreted at a more rapid
rate than the large particles in this ration, they were not excreted as
rapidly as comparable sized particles in rations containing higher per-
centages of the finely ground material.

The effects of particle size on passage rate of a higher level
of feed intake administered by'a method of force feeding animals are
shown in figure h. The graph shows the larger particles to be excreted
faster at the beginning of the collection period than other sizes but
at a much slower rate after 8h hours. All particle sizes decreased in
rate of passage in contrast to the same ration consumed at lower levels.

However, observations on steers that voluntarily consumed the
same level as steers being forced showed a slower passage rate than the

force fed steers. The fact that increasing the level of intake

 

 

 

3h

 

Annsonv uoaoapawn enema meaneom nevus seas

 

 

        

m3 3: 11.: 0.2 on mm 3 a...

as 05.: xulllla c

H mmnm ”HM. 3

E mm. 11:.

3% Sufism 8
dm
c:
dm
do
d»
do
da
63

 

.moapam onanpmoocoo mason» haonau
can eonou scoops hp uoaoapnam amend swan amonouwae no coaaomewe no ovum .4 enemah

 

pensioxa 3910;312d amen; go 9391u9319d aAIJEInan

 

 

 

35

decreased the rate of passage of inert particles in contrast to the effect
of feeding the same ration at lower levels is contrary to the results
obtained by other researchers (Balch, 1950; Blaxter gt 11., 1956 and Cam-
pling and Freer, 1961). These workers reported that increasing the feed-
ing level resulted in an increase in the rate of passage of residues through
the digestive tract. The exact causes of the reduced rate of passage in
this study are unknown; however, two theories may be postulated. First,

the method of force feeding may cause some digestive disturbances which

in turn may alter the rate of feed passage. Second, the higher level of

 

intake may cause distention of the rumen with the feed leading to stony
of the rumen musculature. If the latter occurs, then it is likely that a
10 day preliminary period is insufficient for such a study. From obser-
vations shown in figure 5, it seems unlikely that the method of feeding
is the cause of a slower passage rate of inert particles. Two steers con-
suming the same amount of feed made into a slurry and two steers which
refused to consume this amount of feed were force fed as previously
described. These observations show a more rapid rate of passage for
force fed steers than for those consuming the feed voluntarily. From
this and daily observations of the force fed animals it is likely that
force feeding increases the fill of the rumen. Some preliminary ob-
servations with force feeding were made prior to the start of this
experiment.

Two animals were force fed at the rate of 1%% of their body
weight for 10 days without observing any abnormal disorders. The level

of one steer was increased to 2i% of its body weight. The animal showed

 

36

A9305 uoaoapmsn enema wan—"boom no»: 05m.

 

 

 

m3 3: a: 8H 8 mm. 3 ”a
p . P > \|I\ \ C
\\. x
.\e \\O\
. . exams“ hmmvmsao> \\L\\ \xx. dH
.uu..|. wmauoou voomoh .\\ .\\.
.\ \\ you
\.\
.\. \.\ an
\ x
. \ d:
\ .\
\
o \
\\\\\ .\\ dm
\
\
a \\
\ \. do
. x
\
.\ .2.
\\
. \
e\
s \
\\\\\ .\
\\
\. \ \.\ be
a \\ -\
m\
.t\\\ 62

.mmacoou bouncy use oxen-a hmopmsaob
he Hosea ones as new unseen museum» noaoapmmn enema no noaponoxo Ho seam .m enemah

panazoxe 8913;319d amen} go afienusoxsd aqusInmno

 

 

disc

high

weigh
conte

Ihove

the 14
the an
this I
with a
Tom

relain

acret e
corn co
inert p4
fitter t
filter r
Pltiol
t0 the c
traction
1' m1.
been Pet

Th0" ad

 

 

37

discomfort from the increased feed with rectal temperatures ranging as
high as 107°F. The animal died on the ninth day on this level of intake
and was examined shortly after death. The reticulo-rumen contents
weighed 117 pounds. The intestine was almost empty and the abomasal
contents appeared to have a higher dry matter content than normal and
showed some indication of blocked passage at the pyloric valve.

It can be observed in figure h that the initial excretion for
the large inert plastic particles (h.76 mm) in ration 3 was faster than

the small particles. This may have resulted from the low recovery of

 

this size particle. Less than 25% of these particles were recovered,
with some steers showing no excretion during the experimental period.
These particles were probably retained in the reticulo-rumen and may
remain in this compartment for several weeks.

Figure 6 gives the cumulative percentage of inert particles
excreted when fed with ration h, a concentrate ration containing 20%
corn cobs. Statistical analyses showed that the rate of passage of
inert particles fed with this ration was significantly (P-<:0.01)
faster than the same size particles in the other three rations. The
faster rate of passage of the inert particles in the corn and cob
ration in comparison to the all concentrate rations may have been due
to the cobs acting as a physical stimulus increasing the ruminal con-
tractions. If the roughage portion of this ration caused an increase
in ruminal contraction, it may have agitated some particles which had
been retained in the reticulo-rumen from the previous feeding trials.

These additional particles could explain the large percentage recovery of

 

 

 

00H IAOOal hfl IOHOfiOth QEOIH 0nd! HI

-Ecfialh ONIZNDOH O¢lh¢l00l00
IEOHNHU N0 EOfiQOHOND HO CHIN .0

 

.hl‘flh

 

Aunsonv uoaoapmam manna madcoou nevus ends

 

 

was mm: A»: om." Mm m.» m: :w o
a \ .\
as o~.4 alllllt $\\.n\\ 3
as wm.~ wr.l.ux t\\ .0. 0H m
E! mHA . . x\ +\\ m.
E a bal'll. \ e
mam $\ \\\.x U.
33 363.5 .\ + \ cm a
\ x. \ d
x .\ m
+ 1 \ on a
\ x a
\ \ o \ mm
a. +\ x s
\ I no
\ xx . \ 0: a
i, \+ \\ m.
\ \

\.\V cm W
1
\.\ . \.\ 3
x \ d
\.\ \\ 8 n
\ . \ 3
. \.\x 1. m
\ o b 3..
¥\ \\ 8
.\.\ \\ \\.\ m

*\ . \
\ \\ \ n
i \\ . \.\ D6 a
\\.H.\ \ \ \ m

\ \a
«\ \\\ cm
a\-\ \\\\a
K\ |||I0\\\‘ m
\u\\\... r3

.moapwn emanuoon evanescence
com snoopn ho uoaoapnag enema ouan anemonuae no coaponomo no spam .0 shaman

 

 

 

 

fed
0! t

1"“10

 

 

39

inert particles which exceeded 100%, when fed with this concentrate-
roughage ration. Eng £3 21. (1965) reported the rate of passage of an
all roughage ration to be as fast as the rate of passage of an all concen-
trate ration. It appears that the roughage portion of the ration may act
as a stimulus to increase ruminal contractions. Lack of rumination was
observed throughout the entire experiment, with animals showing little or
no rumination on all rations. This is in agreement with (Cole and Meade,
l9h8; Balch, 1952 and Agrawala st 31., 1953). Agrawala st 31. (1953)

observed a distinct lack of rumination by cattle and sheep fed purified

 

diets. Cole and Meade (l9h8) and Balch (1952) observed that ruminants
rarely or never ruminated when fed rations of finely ground alfalfa hay;
while Gordon (1958) found that when hay was cut into two inch lengths

the total rumination time actually increased over that of long hay, which
was apparently due to increased physical stimulus.

It was reported earlier (Agrawala st 21., 1953; Cole and Mead,
l9h8 and Balch, 1952) that rumination was rarely observed when ruminants
were fed finely ground feeds or purified rations. The slower rate of
passage of all concentrate ration in comparison to a concentrate-roughage
ration indicates that concentrates may have some inhibiting effect on the
digestive tract. Ash (1959) reported buffered solutions of acetic, pro-
pionic and butyric acids (100-200 mM) at pH 3.65 inhibited reticulo-
rumen contractions. Balch and Rowland (1957) found, when hay alone was
fed to a fistulated cow, there was little variation in the concentration
of total VFA at hourly intervals after feeding. On high concentrate

rations the VFA concentration increased to peak values between two and

 

 

 

no

six hours after feeding. Diets containing only small amounts of hay or
hay in the finely ground state produced the greatest ranges in concen-
trations. It was noted that intraruminal pH varied inversely with the
concentration of total VFA with the lowest pH and the greatest range in
pH occurring on the high concentrate ration.
These results suggest that the rate of passage of feeds through
the digestive tract of steers, as measured by plastic particles, follows
a fairly constant pattern. All curves show somewhat the same general shape,

although some animals excreted the marker more rapidly than others. The

 

excretion curves in figures 2 through 6 show that the time of the initial
appearance of the marker in the feces was between 12 and 18 hours after
feeding. These results agree with the findings of Balch (1950) who found
that stained hay particles appeared in cow feces between 12 and 2h hours
after feeding.

The various calculations of the time the different rations and
particle sizes remained in the digestive tract are shown in table 6. It
is evident from these calculations that the rate of passage of inert
particles was faster when ration h was fed than when the other rations
were fed. The R, 5% and mean time values for ration h are smaller than
for rations l, 2 and 3. It is evident that rations 2 and 3 were retained
in the digestive tract for longer periods than rations l and h. The fast-
er rate of passage for ration b has already been discussed, however it
may be of interest to point out that the percent recovery of the inert
particles for this ration was slightly greater than 100%. The high

level of recovery for the concentrate-roughage ration, which may have

 

b1

 

 

RATE OF PASSAGE OF FOUR SIZES 0F INERT PARTICLES THROUGH
THE DIGESTIVE TRACT OF STEERS WHEN FED IN FOUR RATIONS

 

 

Time index (hrs.)

 

 

Particle
size (mm) B? 55b 80%-5%° Mean tine
0.595 81.1 22.0 99.0 85.1
1.19 88.1 28.0 99.0 91.9
2.38 91.1 28.0 102.0 9h.h
h.76 98.9 3h.0 106.0 100.5
0.595 97.0 30.0 108.0 102.1
1.19 10h.u 37.0 107.0 108.6
2.38 107.9 h8.0 106.0 111.6
b.76 123.1 5h.0 9h.0 116.2
0.595 86.2 26.0 101.0 91.1
1.19 92.2 30.0, 103.0 95.5
2.38 9u.h 30.0 110.0 98.6
h.76 102.6 23.0 131.0 106.8
0.595 66.1 26.0 69.0 73.9
1.19 71.1 27.0 75.0 7h.u
2.38 75.1 28.0 92.0 78.9
b.76 105.1 3h.o 123.0 110.6

 

Mean retention time (Castle, 1956a).
Rate of passage through the omasun, abomasum
and intestines (Balch, 1950).
Rate of passage through the rumen and reticulum (Balch, 1950).
Mean retention time (Blaxter 33 al., 1956).

 

 

 

 

 

 

 

h2

been.due to inert particles remaining in the digestive tract from the

previous feeding may aid in explaining the increased rate of passage.

There were greater differences between steers in the rate of
passage on all concentrate rations than on a concentrate-roughage ration.
The addition of the roughage to the ration lowering the specific gravity
may account for some of the differences by speeding up the passage rate.
However, the passage of the larger particles (h.76 mm) was somewhat
slower than for the same particle size in the basal ration 1. King and
Meore (1957) reported maximum rate of passage of particles with a spe-
cific gravity of 1.20 in a ration of hay and grain. Campling and Freer
(1962), feeding concentrates, reported that the fastest rate of passage
was for particles with a specific gravity of 1.21 as compared with par-
ticles of specific gravity of .96 to 1.02. However these workers state
that for cows receiving all concentrate rations the average mean reten-
tion time in the reticulo-rumen was no longer for particles of specific
gravity 1.h0 than of particles of 1.21 specific gravity.

The results of this experiment show the importance of particle
size in determining the rate of passage of inert particles through the
digestive tract of the steer. With all concentrate rations and concen-
trate plus roughage ration, the rate of passage of inert particles
decreased from the small (.595 mm) to the large size (h.76 mm). The
effects of particle size on the rate of passage probably result from
the rate at which the particles separate from the main mass of digesta
and sink to the floor of the rumen and reticulum. The larger feed

particles are probably retained in the reticulo-rumen until broken into

 

 

 

 

h3

smaller sizes before passing to the onasum with the liquid digesta from
the rumen.

In the four digestion trials, the digestibility of dry matter,
crude protein and gross energy was determined. The mean coefficients
of apparent digestibility are given in table 7. The all concentrate
rations show much higher mean digestion coefficients than the concentrate-

roughage ration.

TABLE 7. «MEAN DIGESTION COEFFICIENTS

 

 

 

Ration 1 2 3 h

D. M. 88.09 89.13 88.58 78.80
Crude protein 82.h2 85.79 83.53 75.21
Gross energy 85.02 86.21 85.hh 75.12
Cellulose 72.h6 75.70 66.33 56.05

 

The ration spending shorter periods of time in the digestive tract
of steers showed a lower mean digestion coefficient than rations with a
slower passage rate. The corn and cob ration (h) which showed the fastest
passage rate through the digestive tract shows a considerable drop in the
digestion coefficients of dry matter, crude protein and gross energy. The
digestion coefficients for all concentrate rations are significantly

(P<<f0.01) greater than for the concentrate-roughage ration.

 

 

 

NJ.

The results of this study indicate that factors which cause an
increase in the rate of passage result in a decrease in digestibility and
the rate of passage as measured by inert particles is affected by the
nature of the ration as well as the size of particles fed. Increasing
the feeding level did not result in a decrease in digestibility, but
the additios of cobs to the ration resulted in a significant (P< 0.01)
increase in the rate of passage and a decrease in the digestibility of
the ration. Blaxter st 31. (1956) reported an increase in the feeding
level resulted in a very slight fall in digestibility of long hay and
a fall in digestibility of the finely ground cubed hay.

The digestibility of all rations in this experiment was very
high, especially the all concentrate rations which were retained in the

digestive tract for long periods of time.

 

 

 

Chapter V

SUMMARY AND CONCLUSION

Eight yearling.Angus steers of uniform weight and age and by
the same sire were used in a series of four trials to study the effects
of particle size and level of intake on the rate of passage of all
concentrate rations and concentrate plus 20% roughage ration. The
treatments were arranged with two steers on each in a reversal type
design so that during the four trials eight observations were made on
each treatment. Inert plastic particles (specific gravity l.h25) with
physical characteristics similar to the feed were used as indicators to
measure the rate of passage. The effects of particle size were studied
by separating the plastic (Delrin Acetal Resin) into groups having a
mean diadeter of b.76, 2.38, 1.19 and .595 mm. ‘Within this size range
the rate of passage of inert particles through the digestive tract
decreased as the size of particles increased. There were highly signi-
ficant differences in the rate of passage of all size particles at the
72, 96, and 120 hour intervals after feeding.

Comparison of rations showed a highly significant difference in
their rate of passage. The finely ground concentrate plus 20% roughage
ration passed at a significantly (P-<:0.0l) faster rate than the finely
ground, coarse cracked corn or the finely ground ration force fed. The

finely ground all concentrate ration passed through the digestive tract

hS

a. "

 

 

 

‘, _i

 

 

 

146

of the steer significantly (P<<:0.01) faster than the coarse cracked
ration. Inert particles in the coarse cracked corn ration passed through
the digestive tract of the steer at a slower rate than the particles in
the other rations. These results indicate the importance of particle size
on the rate of passage of undigested residues through the digestive tract
as measured by the movement of inert plastic particles. The data suggest
that 20% corn cobs in a concentrate—roughage ration stimulated some por-
tion of the digestive tract, increasing the rate of passage of inert par-
ticles in comparison to all concentrate rations. A comparison of these
results with other experiments with mixed rations suggests that the cobs
may act as a mechanical stimulus increasing ruminal contractions speeding
the passage rate.

The results of this study showed that increasing the level of feed
intake of a finely ground all concentrate ration decreased the rate of
passage of inert particles in that ration during the seven day collection
period. Observations on animals voluntarily consuming their allotted
ration plus 0.5% of their body weight more of the finely ground feed with-
out forcing with the plunger type gun showed a decrease in rate of passage.
All particle sizes decreased in rate of passage in contrast to the same
ration consumed at a lower level. However, the force fed steers showed a
more rapid rate of passage than steers with the same level of intake
without force feeding. The faster rate of passage of the inert particles
in the concentrate plus roughage ration indicate that sone physical and/or
chemical changes take place in the digestive tract of steers on rations

of different composition.

 

 

 

 

 

 

 

 

 

147

The ration remaining in the digestive tract for the shortest
period of time showed a significant decrease in its digestibility as
compared to the ration with the longest retention time. The rate of

passage as measured by inert plastic particles was indirectly related
to digestibility.

 

 

 

 

 

 

 

B;

Bel

 

 

LITERATURE CITED

Agrawala, I. P., C. W. Duncan and C. F. Huffman. 1953. A quantitative
study of rumen synthesis in the bovine on natural and purified
rations. I. Protein, dry matter and non-protein nitrogen.

J. Nutr. h9:29.

Ash, R. W. 1959. Inhibition and excitation of reticulo-rumen contrac-
tions following the introduction of acids into the rumen and
abomasum. J. Physiol. 1h?:58.

Association of Official Agricultural Chemists. 1960. Official methods
of analysis. (9th ed.). Association of Official Agricultural
Chemists, Washington, D. C.

Balch, C. C. 1950. Factors affecting the utilization of food by dairy
cows. I. The rate of passage of food through the digestive
tract. British J. Nutr. h:361.

Balch, C. C. 1961. Movement of digesta through the digestive tract.
Digestive Physiology and Nutrition of the Ruminant, p. 23.
The White Friars Press Ltd., London, England.

Balch, C. C., D. A. Balch, S. Bartlett, M. P. Bartrum, V. W. Johnson,
S. J. Rowland and Jill Turner. 1955. Studies of the secre-
tion of milk of low fat content by cows on diets low in hay
and high in concentrates. 6. The effect on the physical and
biochemical processes of the reticulo-rumen. J. Dairy Res. 22:270.

Balch, C. C., D. A. Balch, S. Bartlett, V. W. Johnson and S. J. Rowland.
1952. Factors affecting the utilization of food by dairy'cows.
5. The digestibility and rate of passage of foods during L-
thyroxine administration. British J. Nutr. 6:357.

Balch, C. C., D. A. Balch, V. W. Johnson, S. J. Rowland and Jill Turner.
l95h. Studies of the secretion of milk of low fat content
by cows on diets low in hay and high in concentrates. h.
The effect of variations in the intake of digestible nutrients.
J. Dairy Res. 21:305.

Balch, C. C., D. A. Balch, V. W. Johnson and Jill Turner. 1953. Factors
affecting the utilization of food by dairy cows. 7. The effect
of limited water intake on the digestibility and rate of passage
of hay. British J. Nutr. 7:212.

h8

 

 

 

 

 

 

     

 

 

h9

Balch, D. A. and S. J. Rowland. 1957. Volatile fatty acids and lactic
acid in the rumen of dairy cows receiving a variety of diets.
British J. Nutr. 11:288.

Bell, J. M. 1960. A comparison of fibrous foodstuffs in non-ruminant
rations. 1. Effects on growth responses, digestibility, rates
of passage and ingesta volume. Canad. J. Animal Sci. h0:71.

Blaxter, K. L. and N. M. Graham. 1956. The effect of the grinding and
cubing process on the utilization of the energy of dried grass.
J. Agr. Sci. h7:207. '

Blaxter, K. L., N. M. Graham and F. W. Whinman. 1956. Some observations '
on the digestibility of food by sheep, and on related problems.
British J. Nutr. 10:69.

Blaxter, K. L., F. W. wainman and R. S. Wilson. 1961. The regulation
of food intake by sheep. Animal Prod. 3:51.

 

r—. .—....-—- —._———e lll .

Bouchaert, J. H. and W. Oyaert. 19Sh. A method of collecting fluid
leaving the omasum of sheep. Nature, London 17h:ll95.

Brandt, C. S. and E. J. Thacker. 1958. A concept of rate of food
passage through the gastro-intestinal tract. J. Animal Sci.
17:218.

Campling, R. C., M. Freer and C. C. Balch. 1961. Factors affecting
voluntary intake of food by cows. The relationship between volun-
tary intake of roughage, the amount of digesta in the reticulo-
rumen and the rate of disappearance of digesta from the intestinal
tract. British J. Nutr. 15:531.

Campling, R. 0., M. Freer. 1962. The effect of specific gravity and
size on the mean retention.tine of inert particles in the
alimentary tract of the cow. British J. Nutr. 16:507.

Castle, Elizabeth J. 1956a. The rate of passage of foodstuffs through
the alimentary tract of the goat. 1. Studies on adult animals
fed on hay and concdntrates. British J. Nutr. 10:15.

Castle, Elizabeth J. 1956b. The rate of passage of foodstuffs through
the alimentary tract of the goat. 2. Studies on growing kids.
British J. Nutr. 10:115.

Castle, Elizabeth J. 1956c. The rate of passage of foodstuffs through
the alimentary tract of the goat. 3. The intestines.
British J. Nutr. 10:338.

 

 

 

 

 

 

 

50

Cole, H. H. and S. W. Mead. 191:8. Aiphysical deficiency in the ration
of ruminants. Science. 98:5h3.

Crampton, E. W. 1957. Interrelations between digestible nutrient and
energy content, voluntary dry matter intake, and the overall
feeding value of forages. J. Animal Sci. 16:5h6.

Duncan, D. B. 1955. Multiple range and mmltiple F - tests.
Biometrics. 11:1.

Eng, Jr., K. S., M. E. Riewe, J. H. Craig, Jr. and J. C. Smith. l96h.
Rate of passage of concentrate and roughage through the digestive
tract of sheep. J. Animal Sci. 23:1129.

Ewing, P. V. and F. H. Smith. 1917. A study of the rate of passage of
food residues through the steer and its influence on digestion
coefficients. J. Agr. Res. 10:55.

 

Harris, L. E. and A. T. Phillipson. 1962. The measurement of the flow
of food to the duodenum.of sheep. Animal Prod. h:97.

Hoelzel, Frederick. 1930. The rate of passage of inert materials through
the digestive tract. Am, J. Physiol. 92:h66.

Hogan, J. P. and A. T. Phillipson. 1960. The rate of flow of digesta
and their removal along the digestive tract of the sheep.
British J. Nutr. 1h:1h7.

Johnson, D. E., W. E. Dinusson and D. W3 Bolin. 196k. The rate of
passage of chronic oxide and composition of digesta along the
alimentary tract of wethers. J. Animal Sci. 232hl9.

King, K. W. and W. E. C. Moore. 1957. Density and size as factors
affecting passage rate of ingesta in the bovine and human
digestive tracts. J. Dairy Sci. h0:528.

Lambourne, L. J. 1957. Measurement of feed intake of grazing sheep.
1. Rate of passage of inert reference material through the
§ruminant digestive tract. J. Agr. Sci. h8:273.

Meyer, J. H., R. L. Gaskill, G. S.'Stoewsand and w. c. Weir. 1959.
‘ Influence of pelleting on the utilization of alfalfa.
J. Animal Sci. 18:336.

lMitchell, H. H., T. S. Hamilton and C. H. Kick. 1928. Feeding rate
determines speed of passage. I11. Sta. Rpt. Bul. No. 216, p. 117.

IMoore, L..Ar and 0. B. Winter. 193h. Rate of passage of inert materials
through the digestive tract of the bovine. J. Dairy Sci. 17:297.

 

 

51

Oyaert, W. and J. H. Bouchaert. 1961. A study of the passage of fluid
through the sheep omasum. Res. Vet. Sci. 2zhl.

Phillips, G. D. and G. W. Dyck. 196k. The flow of digesta into the
duodenum of sheep. Canad. J. Animal Sci. hh:220.

Phillipson, A. T. l9h8. A method of measuring the flow of digesta from
the stomach of the sheep. J. Physiol. 107:21.

Phillipson, A. T. 1952. The passage of digesta from the abomasum of
sheep. J. Physiol. 116:8h.

Rakes, A. H., W. W. Hardison, J. Albert, W. E. C. Moore and G. C. Graf.
1957. Response of growing dairy heifers to frequenqy of feed-
ing. J. Dairy Sci. h021621.

Rodrigue, C. B. and N. N. Allen. 1960. The effect of fine grinding
of hay on ration digestibility, rate of passage, and fat content
of milk. Canad. J. Animal Sci. h0:23.

Shalk, A. F. and R. S. Amadon. 1928. Physiology of the ruminant
stomach (bovine). N. Dakota Agr. Exp. Sta. Bull. 216.

Shellenberger, P. R. and E. M. Kesler. 1961. The rate of passage of
feeds through the digestive tract of Holstein cows.
J. Animal Sci. 20:h16.

Singleton, A. G. 1961. The electromagnetic measurement of the flow
of digesta through the duodenum of the goat and the sheep.
J. Physiol. 155:13h.

Snedecor, George W. 1956. Statistical Methods (5th ed.) Iowa State
College Press, Ames, Iowa.

Weller, R. A., A. F. Pilgrim and F. V. Gray. 1962. Digestion of food-
stuffs in the rumen of sheep and the passage of digesta through
its compartments. British J. Nutr. 16:83.

 

 

 

 

VITA

The author of this thesis was born in Broathitt County, Ken-
tucky, April 26, 1927. He attended the Breathitt County School system
and graduated from Breathitt County High School at Jackson, Kentucky
in January 19h8. He entered the United States Navy in 19h5, and was
honorably discharged in 19h6. In 19h8 he enrolled at Lees Junior Col-
lege in Jackson, Kentucky for three semesters. In 19h9 he enrolled in
the College of Agriculture at the University of Kentucky and received
a Bachelor of Science Degree in Agriculture in August, 1951. The
author was employed by the Kentucky Agricultural Extension Service
until February, 1955. He entered Graduate School at the University of
Kentucky in February, 1955, where he held a research assistantship in
the Animal Husbandry Department and was engaged in studies leading to
a Master of Science Degree in Agriculture which was awarded in,May,
1956. He then returned to his position with the Agricultural Exten-
sion Service until January 1, 1957 at which time he was transferred to
the Robinson Agricultural Experiment substation, Quicksand, Kentucky
as its Superintendent. In June 1961 he entered Graduate School at
Michigan State University for two terms. In January 1963 he took.

sabbatical leave and re-entered Michigan State to study toward the
Degree of Doctor of PhilosOphy in Animal Husbandry.

He was married to Lena Myrtle Noble in.March l9h9. They have
three children, Ralph, Ada Ruth and Charlene, ages 13, 8 and 7,

respectively.
52

 

 

 

 

 

APPENDIX

53

 

 

 

 

 

5h

APPENDIX TABLE I

IDENTIFICATION OF.ANIMALS BY RATIONS DURING THE h TRIALS

 

 

 

 

vTrial
Animal number 1 2 3 h

136 h 2' 3 1a
137 2 h 1 3
139 h 2 3 1
11.0 1 3 h 2
11.2 3 1 2 h
1&3 1 3 h ' 2
1116 2 h 1 3
11,7 , 3 1 2 h
aRation 1 Consisted of finely ground corn plus protein,

minerals, and vitaminm.
Ration 2 Consisted of cracked corn plus protein,

minerals and vitamins.
Ration 3 Same as ration 1 fed at a higher level.
Ration h Consisted of finely ground corn plus 20% cobs,

proteins, minerals and vitamins.

 

 

 

 

M.

M.

DIGESTIBILITY OF DR! MATTER BI INDIVIDUAL STEERS

 

55

APPENDIX TABLE II

‘ “_‘—-I' —r

 

 

 

 

 

Steer number
136 I137 139 Th0
11:21.}.
D.M. intake (gms) 28,310.0 28,070.0 28,310. ........
D.M. excreted in
feces (ass) 6,063.0 3,091.0 5,t9o. ........
Percent digested 78.6 89.0 80.
1121.2.
D.M. intake (gms) 28,07h.0 28,070.0 28,07h. 36,351.0
D.M. excreted in
feces (gas) 2,uus.0 5,803.0 3,109. h,088.0
Percent digested 91.3 79.3 88. 88.8
Trial 3
D.M. intake (gm) 37,808.0 27,987.0 37,808. 28,07h.0
D.M. excreted in
feces (gms) h,030.0 3,302.0 h,305. 6,hh6.0
Percent digested 89.3 88.2 88. 77.0
Trial h
D.M. intake (gms) 27,983.0 37,7h7.0 27,9h3. 28,153.0
D.M. excreted in
feces (gms) 2,637.0 3,362.0 2,5h8. 3,539.0
Percent digested 90.6 91.1 90. 87.h

k

 

 

 

 

 

DJ

Pen

 

DIGESTIBILITY OF DR! MATTER BY INDIVIDUAL STEERS

 

 

 

APPENDIX TABIE II CONTINUED

 

 

 

 

 

Steer number
1u2 1h3 186 it? -
2.12.1.3
D.M. intake (gms) 37,270.0 27,952.0 28,070.0 36,270.0
D.M. excreted in
feces (gnu) 5,356.0 2,h33.0 3,088.0 h,261.0
Percent digested 85.6 91.3 89.0 88.6
12211.2
D.M. intake (gnu) 28,000.0 37,088.0 28,109.0 28,000.0
D.M. excreted in
feces (gnu) h,827.o 3,782.0 6,181.0 3,725.0
Percent '~ digested 82 . 8 90 . 7 78 . O 86. 7
Trial 3
D.M. intake (gnu) 28,125.o 28,07h.0 27,987.0 28,125.0
D.M. excreted in
feces (gnu) 3,518.0 5,260.0 8,0h3.o 3,089.0
Percent digested 88.5 81.3 85.6 89.2
111211
13.x. intake (gma) 25,355.0 28,153.0 37,7t7.0 28,125.0
D.M. excreted in
feces (gnu) 5,851.0 2,595.0 5,319.0 5,859.0
Percent digested 78.5 90.8 85.9 79.2

¥

 

 

 

 

 

DIGESTIBILIT! OF PROTEIN BI INDIVIDUAL STEEIB

.APPENDIX TABLE III

57

 

 

 

 

 

Steer number
136 137 Y 139 180
11:12.;
Intake (gma) 8,325.8 8,028.1 h,325.8 -------
Output (gun) 917.3 602.2 839.9 -------
Percent digested 78.8 85.1 80.6 -------
EZ$E£_§
Intake (gma) h,166.1 1,058.1 8,166.1 h,769.3
Output (gms) 565.2 2h0.8 h88.b 816.8
Percent digested 86.h 7h.2 86.0 82.9
Trial 3
Intake (gms) 5,126.7 3,795.1 5,126.7 3,683.3
Output (gnu) 836.6 683.9 759.1 1,035.3
Percent digested 83.7 82.0 85.2 71.9
Trial h
:Intake (gms) 3,926.0 5,303.5 3,926.0 h,591.8
Output (gms) 558.1 696.2 525.1 565.8
Percent digested 85.8 86.9 86.6 87.7

¥

 

 

 

 

DIGESTIBILITY OF PROTEIN BY INDIVIDUAL STEERS

 

 

58

APPENDIX TABLE III CONTINUED

 

 

 

 

Steer nunber
11:2 1143 1116 1117
Trial 1
Intake (gins) 5,1h7.0 3,860.2 h,028.1 5,110.0
Output (gm!) 881.0 536.0 595.0 832.5
Percent digested 82.9 86.1 85.2 83.8
Trial 2
Intake (glee) 3,673.6 [1,866.0 3,701.9 3,673.6
Output (gms) 7701; 802.1 1,011.3 762.2
Percent digested 79.0 33.5 72.7 79.3
Trial 3
Intake (all) h,1hS-6 3,683-3 3,795.1 hams-6
Output (gnu) 616.8 7119.6 827.2 701.6
Percent digested 85.1 79.7 78.2 83.1
Trial 14
Intake (gms) 3,085.7 h.591.8 5,331.6 3,h22.8
Output (gr-a) 891.3 561.5 1,096.3 9311.5
Percent dilgested 71.1 87.8 79.11 72.7

¥

 

 

 

APPENDIX TABLE IV

 

 

DIGESTIBILITY OF ENERGY BY INDIVIDUAL STEERS

 

 

 

 

Steer number
136 137 139 1h0
3118;;
Intake (kca1.) 111,229.0 107,h82.0 111,229.0 ---------
Fecal loss (kca1.) 28,319.0 15,120.0 28,903.0 ---------
Percent digested 7h.5 85.9 77.6 ---------
my
Intake (kca1.) 102,918.0 30,986.0 102,918.O 1h1,697.0
Fecal loss (kca1.) 11,611.0 6,h99.0 18,759.0 19,123.0
Percent digested 88.7 79.0 85.7 86.5
Trial 3
Intake (kca1.) 187,37h.0 109,095.O 1h7,37h.o 107,550.O
Fecal loss (kca1.) 19,767.0 15,7h1.o 21,235.0 29,h21.o
Percent digested 85.6 85.6 85.6 72.6
Trial h
:Intake (kca1.) 108,809.0 1h6,988.0 108,809.0 107,602.0
IPecal loss (kcal.) 12,h9l.O lé,1h6.0 12,082.0 16,001.0
IPercent digested 88.5 89.0 88.9 85.1

g

 

 

APPENDIX TABLE IV CONTINUED

60

DIGESTIBILITY OF ENERGY BI INDIVIDUAL STEERS

 

 

 

 

 

Steer number
1&2 lh3 1&6 1h?
3211.1
Intake (kca1.) l38,681.0 92,830.0 107,h82.0 138,631.0
Fecal loss (kca1.) 25,525.0 12,1h2.0 15,038.0 21,756.0
Percent digested 81.6 86.9 86.0 8h.3
£81.?
Intake (kca1.) 109,1h5.0 1hh,569.0 108,h15.0 109,1h5.0
Fecal loss (kca1.) 21,803.0 17,789.0 28,929.0 18,355.0
Percent digested 80.0 87.7 73.3 83.2
211.3.
Intake (kcal.) 106,930.0 107,550.0 109,095.0 106,930.0
Fecal loss (kcal.) l6,75h.0 23,5h6.0 19,588.0 15,513.0
Percent digested 8h.3 78.1 82.0 85.5
1221.1
.Intake (kcal.) 96,931.0 107,602.0 1h6,988.0 107,521.0
]?eca1 loss (kcal.) 25,hh2.0 12,h77.0 26,197.0 26,938.0
I’ercent digested 73.8 88.0 82.2 75.0

 

 

 

 

 

61

APPENDIX TABLE V

 

 

 

CHANGES IN BODY WEIGHT OF STEERS FED IN

METABOLISM CRATES BY 17 DAY PERIODS

 

 

Steer number

 

 

136 137 139 11.0 11.2 11.3 11.6 11.7
Trial 1
Ration fed h 2 h l 3 l 2 3
Initial weight 6h8 65h 652 616 678 600 676 680
Final weight 670 677 657 --- 7&6 6h8 675 733
Gain or loss (lbs.) 22 23 5 --- 72 88 -1 58
Trial 2
Ration fed 2 h 2 3 l 3 h 1
Initial weight 670 677 657 605 7h6 688 675 733
Final weight 722 70b 700 680 706 700 692 706
Gain or loss (lbs. 52 31 h3 35 -ho 52 15 -27
Trial 3
Ration fed 3 1 3 h 2 h l 2
Initial weight 722 70h 700 6&0 706 700 692 706
Final weight 758 698 730 6th 692 688 68h 73h
Gain or loss (lbs. 36 -6 30 h -1h -12 -8 28
Trial h
Ration fed 1 3 l 2 h 2 3 11
:Initial weight 758 698 730 6th 692 688' 68h 73h
J?ina1 weight 750 735 736 675 696 688 755 750
(3ain or loss (lbs. -8 37 6 31 h 0 71 16

‘

 

 

 

 

62

APPENDIX TABLE VI

TRIAL 1

 

FECAL COLLECTIONS BY PERIODS (gms.)

 

 

Steer number

 

 

Collections 136 137 139 1h2 183 186 1b?
1 220 350 h20 8&0 380 h60 5h0
2 1,200 290 720 600 620 280 820
3 800 h00 980 860 --- 560 9h0
b 1,000 --- 1,190 900 D80 h30 180
5 600 580 1,3h0 660 360 290 880
6 7h0 -—- 970 790 530 630 620
7 870 700 h70 1,000 D80 130 320
8 620 100 1,080 680 290 510 860
9 1,080 --- 1,h20 1,120 --— -—- 600

10 990 580 980 620 1,060 1,060 700
11 8hO 890 1,600 520 --- h9O h60
12 1,270 280 960 760 th -—- 2&0
13 1,820 9&0 2,680 1,660 1,350 1,0h0 1,280
It 1,060 980 2,0hO 1,230 520 980 1,190
15 1,560 1,050 2,000 1,520 930 1,030 780
16 1,5h0 580 2,880 1,3hO 1,060 1,130 580
17 1,390 760 920 1,520 510 980 1,150
18 2,280 1,1h0 2,580 1,hOO 920 710 880
19 1,560 570 990 1,500 250 1,000 1,980
20 1,520 790 1,520 1,500 7hO 1,110 1,610

 

 

 

 

FECAL COLLECTIONS BY PERIODS (gms.)

63

APPENDIX TABLE VI

TRIAL II

 

 

 

 

 

Steer number

Collections 136 139 1&0 1&2 1&3 lh6 1h?
1 520 160 780 780 9ho 1,860 390
2 500 800 780 520 650 1,020 710
3 300 850 260 8h0 270 670 500
h 220 680 1,380 390 930 560 350
5 180 530 25 970 310 hlo 860
6 580 900 1,250 h90 1,860 1,660 “"
7 860 h30 1,070 780 h90 750 h70
8 330 130 h80 23o h20 1,0ho 590
9 --- h6O 66o hzo 380 860 230
10 530 -—- 580 1,010 590 1,590 900
11 170 510 720 720 500 1,020 héo
12 300 580 190 570 790 820 h20
13 820 1,000 780 1,390 750 2,0ho 9ho
11 720 110 760 1,5hO 1,320 2,100 900
15 660 960 1,060 1,h30 600 2,870 1,130
16 310 860 950 820 1,020 1,080 1,670
17 860 500 1,760 1,130 1,300 2,670 1,620
18 650 710 1,000 9ho 770 1,710 830
19 5145 690 1,530 1, 280 1,130 1, 970 790
20 750 720 Steer 1,080 750 1,150 880

died

 

 

 

 

APPENDIX TABLE VI

68

TRIAL III

FECAL COLLECTIONS BY PERIODS (gms.)

 

 

 

 

 

Steer number

Collections 135 136 137 139 182 183 186 187
1 1,580 580 650 920 820 670 730 260
2 500 360 510 530 280 750 700 520
3 860 220 580 600 280 580 660 360
8 930 880 220 330 230 1,780 860 900
5 810 720 620 600 890 820 830 310
6 1 , 350 360 280 860 360 980 320 880
7 290 670 820 550 620 530 -—- 890
8 1,290 880 680 330 250 950 1,260 550
9 530 880 800 510 550 710 500 ---
10 1,180 610 190 990 1,020 1,020 810 880
11 280 310 880 280 660 800 780 180
12 980 760 280 610 870 1,170 500 670
13 1,780 960 1,180 1,210 1,260 1,820 1,380 580
18 2,250 1,220 580 1,060 1,030 1,700 1,070 770
15 1,690 760 860 1,110 1,080 1,720 610 790
16 2,230 1,880 830 1,380 1,210 1,980 1,310 980
17 1,870 860 700 1,580 1,100 1,650 770 960
18 1,980 880 650 500 1,060 1,370 780 790
19 1,880 1,390 1,190 920 1,280 1,330 1,790 920
20 1,680 880 880 1,870 850 1,810 990 810

 

 

 

 

FECAL COLLECTIONS BY PERIODS (gms.)

APPENDIX TABLE VI

65

TRIAL IV

 

 

 

Steer number

 

 

Collections 135 136 137 139 182 183 186 187
1 --- 390 220 820 1,080 1,000 880 800
2 850 320 650 520 880 380 880 500
3 830 ——— 600 200 1,000 ——- 600 790
8 260 880 550 230 760 860 830 760
5 800 360 680 300 910 --- 760 680
6 620 290 360 310 1,830 580 1,260 1,800
7 860 280 160 --- 1,380 620 880 520
8 870 860 760 880 680 170 300 780
9 350 260 900 500 390 570 1,180 1,860

10 980 870 290 780 870 270 1,530 1,360
11 180 280 260 --- 220 630 590 1,080
12 900 660 700 390 —-- 250 770 990
13 920 780 920 180 1,200 900 2,190 2,880
18 1,090 780 980 980 1,710 780 1,810 2,130
15 1,270 620 850 1,270 2,180 800 1,180 1,920
16 1,050 610 590 620 1,670 750 2,200 2,000
17 910 910 860 880 2,080 580 1,080 1,150
18 1,300 880 600 920 2,010 720 1,880 2,210
19 1,190 580 610 680 2,370 690 2,560 1,560
20 990 950 550 810 1,160 680 960 1,680

 

 

 

 

66

APPENDIX TABLE VII

ANAIKSIS OF VARIANCE OF MEAN PASSAGE

RATE AT 72, 96 AND 120 HOURS

 

 

 

 

Mean
Source of variation DF SS Square F-ratio
Total 127 67 , 373. 28
Replications 1 888 . 26
Treatments 63 86,816. 25 736. 77 2 . 268a
Rations 3 7,972.96 2,657.65 8.1808
Particle size 3 19,881.20 6,613.73 20.356b
Steers 3 2,057.83 685.81 2.111
R x P S 9 2,152.68 239.19 .736
R x S 9 5,588.81 620.53 1.910
P s x s 9 3,951.39 839.08 1.351
R x P S x S 27 8,855.78 179.88 .558
Error 63 20,868.77 328.90

 

a
Significant (P < 0 . 05)

b
Highly significant (P <0.01)

 

 

 

 

67

APPENDIX TABLE VIII

ANAIJSIS OF VARIANCE OF DRY MATTER DIGESTION

 

 

 

 

 

 

 

 

Mean
Source of variation DF SS Square F-ratio
Total 31 698.11
Ration 3 580. 33 160.11 73. 88‘
Steers 7 71.97 10.28 8.71a
Error 21 85.81 2.18
aHighly significant (P <0 . Ol)
DUNCANB MULTIPLE RANGE TEST
78.80 88.09 88.58
89.13 10.33 1.08 .55
88.58 9.78 .89
88.09 9.29
Difference for
SP 128]: VEJHQ significance
1‘ I 7h ha 31 3 e 18
3 .78 8.20 3.11
2 .78 8.02 2.97

 

 

 

 

 

68

APPENDIX TABLE IX

ANALYSIS OF VARIANCE OF CRUDE PROTEIN DIGESTION

 

 

 

 

 

 

 

 

Mean
Source of variation DF SS Square F-ratio
Total 31 735.88
Ration 3 501 . 95 167.32 32. 55a
Steers 7 125.89 17.93 3.89
Error 21 108.08 5.18
81113th significant (P< 0.01)
DUNCANS MULTIPLE RANGE TEST
75.21 82.82 83.53
85.79 10.58 . 3.37 2.26
83.53 8.32 1.11
82.82 7.21
_ Difference for
Sr Table value significance
8 1.138 8.31 8.89
3 1.138 8.20 8.76
2 1.138 8.02 8.59

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

    

 

777“

WW
3 O 71 0 5 7

771717

77777777