HERITABILHY ESTIMATES, ceammsow COEFFICIENTS AND ’. .V OTHER PARAMETERS m Boaww'ra gum; * ‘ .~ .- Thesis for the Degree of Ph. D. MICHIGAN STATE UNWERSETY HANNA t). GEORGIS 1970' WWHWWWWWM L 31293011065897 , ' LIBRARY ' Michigan State University This is to certify that the thesis entitled Heritability Estimates, Correlation Coefficients and Other Parameters in Bobwhite Quail presented by Hanna D. Georgia has been accepted towards fulfillment of the requirements for 1311.1). degree in Poultry Science / %&4 M '. :(JL Major professor Date April 6, 1970 0-169 ~ s..":.o «12‘.» 1:) NOV-‘2 9 23; 1V»: EL HERITABILITY ESTIMATES, CORRELATION COEFFICIENTS AND OTHER PARAMETERS IN BOBWHITE QUAIL By Hanna D; Georgis AN ABSTRACT OF A THESIS Submitted to Michigan State University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Department of Poultry Science 1970 ABSTRACT HERITABILITY ESTIMATES, CORRELATION COEFFICIENTS AND OTHER PARAMETERS IN BOBWHITE QUAIL By Hanna D. Georgis Experiments were conducted to determine heritability estimates and correlation coefficients of Bobwhite quail body weights and to deter- mine average body weight, growth rate and mortality during the growing period at 4, 8, 10, 12, 14, 16, 18 and 20 weeks of age for Bobwhite quail males, females and combined sexes. Heritability estimates for egg pro- duction and percent hen-day egg production for a six-month period from 12 to 18 months of age were also determined. The experimental stock consisted of a parental generation of 50 pairs (male and female) of Bobwhite quail and the first filial generation offspring secured from six hatches of eggs from the parental generation. Birds of both generations were kept in Petersime chick starting batteries during the growing periods. The chicks were wing banded and were dis- tributed randomly with approximately 50 birds per battery compartment. They were weighed at four and eight weeks of age and at two week inter— vals thereafter to 20 weeks of age. Fifty pairs (male and female) of each generation were randomly distributed in separate cages and kept for egg production. From both generations of birds, eggs were gathered and Hanna D. Georgis recorded daily during the six-month experimental periods from 12 to 18 months of age. Feed and water were kept before the birds continuously. Light was controlled automatically at 15.5 hours per day and room tempera- ture was kept approximately constant all year round. Birds from both generations were housed in the same room. Heritability estimates for Bobwhite quail body weights were cal- culated by two methods: (1) regression of offsprings on parents and (2) variance components of full sibs. By regression, heritability estimates of body weight of Bobwhite quail from four to 20 weeks of age ranged from -O.10 to 0.22, from 0.08 to 0.52 and from 0.05 to 0.25 with an average of 0.03, 0.32 and 0.14 for males, females and combined sexes, respectively. The expected average for combined sexes (0.18) was higher than that realized. Female esti- mates were consistently higher than those of males at the corresponding ages. By variance components, heritability estimates of body weight of Bobwhite quail at the above mentioned ages were in a range from 0.19 to 0.62, from 0.26 to 0.52 and from 0.26 to 0.54 with an average of 0.47, 0.42 and 0.43 for males, females and combined sexes, respectively. The expected values were in rather close agreement with those of the combined estimates. All the estimates were positive values. Differences in heritability estimates computed by the two methods are possibly due to sampling errors, dominance, maternal effects and/or sex-linkage. It appears that selection of Bobwhite quail breeders on the basis of body weight would be most effective when the quail are from 16 to 20 Hanna D. Georgis weeks of age with best results at 18 weeks of age without regard to the method Of computing the heritability estimate or to sex of birds. At 18 weeks of age Bobwhite quail can be sexed with 100 percent accuracy on basis of external appearances. It should be possible to forecast the amount of improvement expected in body weight of succeeding generations of growing quail. The heritability estimate for egg production computed by the re— gression method for the six-month period from 12 to 18 months of age was 0.37. It appears that egg production in Bobwhite quail is a moderately heritable trait. It should be possible to forecast the amount of improve- ment in succeeding generations when selection of breeders is based upon egg production records. Correlation between four-week body weight and subsequent weights to 20 weeks of age in Bobwhite quail were in a range from 0.38 to 0.80. All the possible correlations of body weight between the different ages were in a range from 0.38 to 0.99 and were significant at the 0.05 level (a = 0.05), while 69 out of the 84 possible correlations were significant at the 0.01 level (a = 0.01). Bobwhite quail body weights were consistently correlated with sub- sequent weights at different ages; therefore, body weight records at four weeks of age or any subsequent age during the growing period could be used as a selected index for improvement in this character. Bobwhite quail chicks in the parental and first filial generation gained weight rapidly to eight weeks of age and had attained 74.3 and 72.9 percent of their adult weight by that age, respectively. The best growth rate during the growing period was between four and eight weeks Hanna D. Georgis of age. At very early ages the females were heavier than the males; however, at ten weeks of age the males were heavier than the females, a position which they maintained to 20 weeks of age. Body weights of parental and first filial generation Bobwhite quail were in close agree- ment at corresponding ages during the growing period. From a practical point of View Bobwhite quail body weight measure- ments could be a useful index in quail breeding and would be an effec- tive tool for selection and improvement. Selection could be practiced at an early age or at any age during the growing period. The average egg production in Bobwhites for a six month period from 12 to 18 months of age was 105.5 and 109.2 and the percent hen-day egg production was 61.1 and 61.4 for P1 and F1 generations, respectively. It appears that individual egg production records could be a useful index for selection of breeders. Mortality in Bobwhites was inversely proportional to age. The highest mortality (34.8 percent) was recorded during the first four weeks of age. Mortality was only 5.8 percent for the period between four and 20 weeks of age and was 0.0 percent between 18 and 20 weeks of age. HERITABILITY ESTIMATES, CORRELATION COEFFICIENTS AND OTHER PARAMETERS IN BOBWHITE QUAIL By . >\. Hanna DI Georgis A THESIS Submitted to Michigan State University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Department of Poultry Science 1970 ACKNOWLEDGEMENTS The author is most grateful to Dr. Theo H. Coleman, Professor of Poultry Science for his guidance and direction of this research project and for his constructive criticism in preparing of this manuscript, for his encouragement and assistance during the present graduate program. His generous patience and counseling will always be remembered. Appre- ciation is also extended to the members of the Graduate Committee, Dr. V. L. Sanger, Dr. E. M. Smith and Dr. C. J. Flegal. The author also wishes to express his sincere appreciation to Dr. Howard C. Zindel, Chairman of the Department of Poultry Science at Michigan State University for providing the facilities for this study, and to the people of the State of Michigan for allowing him to use the facilities of the University. He is also indebted to the remainder of the Poultry Science Staff and fellow graduate students for their COOpera- tion, suggestions and continued help. The author extends his sincere gratitude to his wife Wadia for her continuous encouragement, support and inspiration throughout his career 0 ii TABLE OF CONTENTS LIST OF TABLES . . . . . . . . . . . . . . . LIST OF FIGURES . . . . . . . . . . . . . INTRODUCTION . . . . . . . . . . . . . . . OBJECTIVES . . . . . . . . . . . . . . . . REVIEW OF LITERATURE . . . . . . . . . . . . Heritability and Correlation . . . . . . Growth Rate and Body Weight . . . . . . . Egg Production . . . . . . . . . . . . . . Mortality . . . . . . . . . . . . . . . EXPERIMENTAL PROCEDURE . . . . . . . . . . Stock Used . . . . . . . . . . . . . . . . Housing and Management . . . . . . . . . . Incubation . . . . . . . . . . . . Growing and Breeder Quail . . . . . . . Records . . . . . . . . . . . . . . . . Estimations and Statistical Procedures . RESULTS AND DISCUSSION . . . . . . . . . . . Heritability Estimates for Body Weight. . Heritability Estimates for Egg Production Correlation Coefficients of Body Weights . Growth Rate and Body Weight . . . . . . . Egg Production . . . . . . . . . . . . . . MOrtality . . . . . . . . . . . . . . . . SUMMARY AND CONCLUSIONS . . . . . . . . . LITERATURE CITED . . . . . . . . . . . . . . APPENDIX 0 O O O O O O O O O O I O O O O 0 iii Page iv 13 14 15 l6 l6 16 18 19 21 21 26 26 34 35 43 51 51 56 59 63 10. 11. LIST OF TABLES Composition of Quail Breeder Ration . . . . . . . . . . Record of Bobwhite Parental and First Filial Generation . . . . . . . . . . . . . . . . . . . . Heritability Estimates for Body Weight in Bobwhite Quail from Four to 20 Weeks of Age and for Egg Production from 12 to 18 Months of Age (Regression Method) . . . . . . . . . . . . . . . . . . . . . . . . Heritability Estimates for Body Weight in Bobwhite Quail from Four to 20 Weeks of Age (Variance Components Method) . . . . . . . . . . . . . . . . . . The Correlation Estimates of Body Weight in Bobwhite Males from Four to 20 Weeks of Age . . . . . . . . . . The Correlation Estimates of Body Weight in Bobwhite Females from Four to 20 Weeks of Age . . . . . . . . . The Correlation Estimates of Body Weight in Bobwhite Combined Sexes from Four to 20 Weeks of Age . . . . . . Average Body Weight (Grams) and Growth Rate (Grams Gain/Bird/Day) of First Filial Generation of Bobwhite Quail from Four to 20 Weeks of Age (Growing Period) . . . . . . . . . . . . . . . . . . . Average Body Weight (Grams) and Growth Rate (Grams Gain/Bird/Day) of Parental Generation Bobwhite Quail from Four to 20 Weeks of Age (Growing Period) . . Egg Production of Parental and First Filial Generation Bobwhite Quail from 12 to 18 MOnths of Age (Six— Month Period) . . . . . . . . . . . . . . . . . . . . . Mortality of First Filial Generation Bobwhites from Hatching Time to 20 Weeks of Age (Growing Period) . . . iv Page 17 22 27 30 36 37 38 44 46 52 53 LIST OF FIGURES Figure Page 1. Heritability Estimates for Body Weight in Bobwhite Quail from Four to 20 Weeks of Age (Regression Method) 0 O O O O O O O I O O O O O I O O C O C O O O O I 28 2. Heritability Estimates for Body Weight in Bobwhite Quail from Four to 20 Weeks of Age (Variance Components Method) . . . . . . . . . . . . . . . . . . . 31 3. Correlations of Body Weight in Bobwhite Males from Four to 20 Weeks of Age . . . . . . . . . . . . . . . . . 40 4. Correlations of Body Weight in Bobwhite Males from Four to 20 Weeks of Age . . . . . . . . . . . . . . . . . 41 5. Correlations of Body Weight in Bobwhite Combined Sexes from Four to 20 Weeks of Age . . . . . . . . . . . 42 6. Average Body Weights of First Filial Generation Bobwhite Quail from Four to 20 Weeks of Age (GrOWing Period) 0 O O O O O O O O O O I O O I O O O C O 45 7. Average Body Weight of Parental Generation Bobwhite Quail from Four to 20 Weeks of Age (Growing PeriOd) O I O O O O O O O O O O O I O O I O O O O O I O O 47 8. Comparison of Body Weight of Combined Sexes in Parental and First Filial Generation Bobwhite Quail from Four to 20 Weeks of Age . . . . . . . . . . . 48 9. Mortality of First Filial Generation Bobwhite Quail from Hatching Time to 20 Weeks of Age . . . . . . . . . . 55 INTRODUCTION The Bobwhite quail (Colinus virginianus and its races, Aldrich, 1946) has the possibility of being useful as a pilot animal for poultry research. In addition, in nature Bobwhites are considered to be one of the first among the game birds in America. Additional basic information on the Bobwhite is needed. Little or no information on genetic parameters such as heritability and correla- tion is available. Poultry scientists are generally in agreement that the amount of genetic change of reproductive traits in poultry depends on the size of the genetic variances and the heritability of traits studied. The heritability estimate is a key to improving the population by breeding methods. It is considered one of the most important para- meters in breeding and in forecasting the amount of improvement expected in each generation. The correlation coefficient is a measure of how closely two char- acters tend to vary. Accurate estimates of correlation allow the pre— diction of direct and correlated responses in one trait resulting from selection for another single trait. Good information is a prerequisite for good decisions. Such in- formation might be useful, whether Bobwhite quail were raised for profit or were used as a pilot animal. 2 Reviews reveal no estimate of heritability in Bobwhites for body weight or egg production or for any other traits, but in the last 20 years numerous studies have been made providing heritability estimates for traits in chickens and turkeys and they are high enough for selection to be reasonably effective. The present study was undertaken to estimate the parameters of heritability of body weight during the growing period and heritability of egg production, to determine correlation of body weight during the growing period, to determine the growth rate and the average body weight and the mortality during the growing period and egg production in Bob- white quail from 12 to 18 months of age. OBJECTIVES The objectives of this experiment were: To determine heritability estimates for body weight in the Bobwhite quail from four to 20 weeks of age. To determine heritability estimates for egg production in Bobwhite quail for a six-month period from 12 to 18 months of age. To determine correlation coefficients for body weight in Bobwhite quail from four to 20 weeks of age. To determine the growth rate of Bobwhite quail during the growing period and the average body weights at various times from four to 20 weeks of age. To determine egg production of Bobwhite quail from 12 to 18 months of age. To determine mortality in Bobwhite quail during the growing period (to 20 weeks of age). REVIEW OF LITERATURE Heritability and Correlation The heritability estimate is a key to improving the population by breeding methods. It is considered one of the most important parameters in animal and poultry breeding. Lush (1948) stated as follows: "A characteristic is not inherited as such. The thing inherited is the ability to respond in a given manner to a given environmental circum- stance. The observed phenotype is the net result of these inherited potentialities and the environmental circumstances, such as nutrient supply, temperature, diseases, accidents, etc., which they encounter. Between the genes which are transmitted and the observed phenotype of the plant or animal is a considerable gulf of time and of chemical and physical processes in which the genes interact with environmental sub- stances, forces and conditions, and also with the primary and secondary products of each other. The complete story of all that happens in this period includes the whole subject matter of embryology and the physiology of growth and development. Heritability is a statistic which describes a certain population in terms of observed phenotypic variance due to differences between individuals in their heredity." Heritability, as defined by Lush (1949) is: "The fraction of the observed or phenotypic variance which was caused by differences between the genes or genotypes of the individual." 4 5 Jull (1952) stated that heritability can be measured by several different means, but regardless of the mechanics used, the essential factor is to determine the relative importance of heredity and environ- ment in contributing to the variation among individuals of a given pOpu— lation. The variation within inbred lines can be compared with the variation within random breeding populations to secure an estimate of heritability. He mentioned that another method of estimating herita- bility is to study the relationship between parent and offspring for a given trait and that this method is rather commonly used, but it has the disadvantage that the estimate is apt to be too high, since the parents and offspring are, in general, apt to have some environmental factors in common. He stated, however, that this objection is not serious in poultry and in a more limited sense, heritability refers only to the average influence of the genes, and is used when the main purpose is to express what fraction of the phenotypic variance between parents may be expected to be recovered in their offspring. He stated further that it is this latter expression of heritability that is of the greatest value in predicting the amount of improvement that can be expected. Probably the most widely used method of estimating heritability is to study the sources of variation within a population. Heritability is studied by calculating differences among individuals rather than by using absolute values. In statistical procedures, these differences are used to secure a value which is a measure of variations and is called variance. If a character is highly heritable, then the individual's record should be given first consideration. In this case, the phenotype is a reliable expression of the genotype. If a character has a low degree of heritability, meaning that the phenotypic expression is not a very 6 reliable estimate of the genotype, then it will be necessary to use the sib test, progeny test, or some other method of making selection in which less importance is attached to the record of the individual and more importance to the estimate of its genotype (Jull, 1952). A further use of heritability data is indicated by Lerner (1958) who suggested that when the heritability of a character is known and the difference between the records of the flocks as a whole and the records of the stock used for breeders is likewise known (called selection dif— ferential), it is possible to forecast the amount of improvement expected in each generation. Lush (1956) stated that the correlation coefficient is a measure of how closely two things tend to vary in the same direction. Examples of this are the tendency in human data for father and son both to be tall or both to be short, and the tendency for tall men to weigh more than short men. The coefficient for measuring degrees of correlation is technical enough so that considerable practice in computing it on various kinds of data is usually necessary for proficiency in understanding it. The coefficient of correlation is expressed on a scale running from +1.0, where two characteristics vary in perfect step with each other, through zero, where there is no correspondence at all, to -1.0, where there is a perfect tendency to vary in exactly opposite directions from each other. Lerner and Donald (1966) stated that phenotypic correlations be- tween different traits are the result of combination of genetic and environmental correlations. Many estimates of heritability of most productive characters in chickens and turkeys already exist in published literature; rather fewer correlations have been reported. No documented reports could be located 7 concerning heritability estimates or correlation of any productive char- acters for the Bobwhite quail; they have received little or no attention from researchers and have been largely neglected. Consideration of the Japanese quail as a pilot animal for poultry investigations has recently received considerable attention and several estimates of some genetic parameters have been reported by researchers. Heritability estimates for mature Japanese quail body weight (134 days of age) from sire components was 0.36 and for percent hen-day pro- duction was 0.46 (Marks and Kinney, 1964). For four-week body weight this estimate was 0.59 for males and 0.47 for females (Yoshida and Collins, 1967). The realized heritability for six—week body weight was estimated at 0.14 (Collins and Abplanalp, 1965). Marks and Lepore (1968) conducted an experiment on Japanese quail with two different protein levels (28% and 20% with 0.2% thiouracil to depress growth). They found that heritability estimates for four-week body weight computed by the regression method were 0.48 and 0.39, respectively, and after five genera- tions of selection on the two respective diets, the birds at six weeks of age weighed an average of 23 and 18 grams more than their respective unselected controls. Hazel and Lamoreux (1947) reported that the heritability esti— mates from components of variance of 22-week body weights for White Leghorn chickens hatched in spring and summer were 0.226 and 0.316, respectively, with standard errors of 0.05. Phenotypic selection for this characteristic was effective in promoting genetic improvement quite rapidly. Wyatt (1954) reported the heritability estimates from regression of daughters on dams of body weight in nineteen different breeds of chickens (both meat type and egg production type) as 0.40 with a range 8 of i:0.15 at eight weeks of age and 0.18 i 0.15 at 23 weeks of age and from full-sib correlation they were 0.46 and 0.31 for the mentioned ages, respectively. Goodman and Godfrey (1956) found that heritability of body weights for New Hampshire and Silver Oklabar chickens from variance components and from intrasire regression of offsprings on dams at nine weeks and at ten months of age, averaged at 0.43 and 0.47, respectively and that heritability estimates calculated by variance components were slightly higher than those computed by use of regression. They found that in- dividual selection was the most efficient selection method to improve either broiler body weight or mature body weight in these pOpulations. Moyer gt_§l. (1962) found that heritability estimates from the sire variance components appeared in general to increase slightly be— tween four and eight weeks of age. Sire component heritability estimates from the crosses of two lines of broiler chickens at four and eight weeks of age averaged 0.20 and 0.24, respectively, for males and 0.26 and 0.35, respectively, for females. Heritability estimates from the dam variance components compared to those from the sire were somewhat larger and generally decreased between four and eight weeks of age. Average heri- tability estimates from the dam variance component for male progeny at four and eight weeks of age were 0.72 and 0.65, respectively, and for females 0.81 and 0.57, respectively. Siegel (1962) stated that body weight in chickens at eight weeks of age is a quantitative characteristic influenced by complex physio- logical mechanisms. He made a summary of 176 published heritability estimates of body weight obtained for chickens 6 to 12 weeks of age and found that the median heritability was 0.41 with an interquartile range 9 of 0.29 to 0.54. This would indicate that in most of the populations studied, body weights at these ages had a moderate to high heritability. Although the overall range of the estimate given above may appear wide, it should be remembered that several methods of estimations were employed and that the parameters were obtained for many different populations. Discussions of these and other factors which also influenced the magni- tude of the heritability estimates are given by Lerner (1950, 1958) and Falconer (1960). Siegel (1962), after reviewing the literature noted that body weight in chickens was generally reported to have a moderate to high heritability, and stated that, if most of the gene action is of the additive type, individual phenotypic selection should be effective in changing the population means for this characteristic in either an up- ward or a downward direction. He found that a single generation of mass selection resulted in highly significant differences between lines for the selected trait. These differences increased each generation and in the F4 high weight line, females and males weighed 294 and 321 grams more, respectively, than those in the low weight line. Natural selec- tion was a minor factor in influencing the short—term response to arti— ficial selection for eight-week body weight and heritability estimates of White Plymouth Rocks for eight week body weight, calculated by regres- sion, in the F generation for males, females and combined sexes were 1 0.23, 0.21 and 0.22, respectively, and calculated by variance components were 0.37, 0.39 and 0.38, respectively. Siegel (1963) reported that the mean heritability estimates, based on full—sib correlation, for unselected body weight in White Plymouth Rocks at four weeks of age were 0.43 for males and 0.53 for 10 females with a combined estimate of 0.48. The mean heritability esti- mates at 24 and 38 weeks of age were 0.46 and 0.38, respectively. These heritability estimates for body weights were in close agreement with the mean estimates reported by Siegel (1963) of 0.47, 0.44 and 0.43 for four-, 24— and 38-week weights, respectively. Amer (1965) found that the dam's contribution to estimates of heritability of body weight in the Fayoumi chicken was higher than that of the sire. The estimate became higher as chicks advanced in age, being 0.36, 0.54 and 0.76 on the basis of both parents' contributions at hatching, at four weeks of age and at eight weeks of age, respectively. This may be explained by the great influence of environment when the chicks are young. Kinney £5 31. (1968) found that the average heritability esti- mates in White Leghorn chickens were 0.45, 0.63 and 0.63 for eight-, 32- and 55-week body weight. El-Ibiary and Shaffner (1950), investigating the heritability of rate of growth in chickens, found that the maternal effect was rather important during the early growth period but was largely overcome by the sixth week of age. With respect to egg production in the domestic fowl, it has been reported by Lerner and Cruden (1948) that the heritability estimate of the annual egg production for the first laying year in Single Comb White Leghorns was nearly constant throughout the year and in the neighborhood of 0.33, while it was estimated as 0.34 by Shaffner (1946). King and Henderson (1954) found in their studies of White Leg- horns that the heritability estimate of 0.312 for the annual egg produc- tion agreed very closely with the average of 0.31 which they computed 11 from published estimates of other investigators. The estimation of Waring g£_al. (1962) was 0.329 which was very close to that of Lerner and Cruden (1948). A heritability estimate of 0.232 was reported by Jaffe (1966) for this character. Heritability estimates of egg produc- tion in White Leghorn chickens by Kinney g£_§l, (1968) were 0.18, 0.10, 0.08 and 0.13 from the first egg production time to 40 weeks of age, 41 to 55 weeks of age, 56 to 70 weeks of age and total percent production, respectively. Amer (1967), in his studies on the Fayoumi chicken, the native fowl of Egypt, found that the estimate of heritability of the annual egg production during the first year of egg production was 0.14. Turkeys are noted for extreme sex dimorphism in body weight; the females of most varieties weighing about 65 percent as much as males at 24 weeks of age. The sex difference of body weight in turkeys is in- fluenced by heredity, the females are less variable than males in body weight (Shaklee g£_gl,, 1952), and 60 percent of the variation of body weight in turkeys is due to sex (Asmundson, 1948). A survey of the literature reveals only a few estimates of the heritability of body weight in turkeys. These estimates have been sum- marized by Nestor EE_21' (1967). They found the averages of these esti- mates were 0.40, 0.42, 0.43 and 0.36, respectively, for turkeys in the age group 0 to 8, 9 to l6, 17 to 24 and greater than 24 weeks of age. Estimates varied considerably because of age, sex and environmental factors. Some reported heritability estimates for this trait in turkeys were 0.16 to 0.71 by Abplanalp and Kosin (1952); an average of 0.30 with a range of 0.18 to 0.50 by Goodman 35 a1. (1954); from 0.025 to 0.464 (males) and from 0.003 to 0.322 (females) by Bumgardner and Shaffner 12 (1954); a range of 0.23 to 0.33 for males and 0.59 to 0.61 for females by McCartney (1955); and 0.50 to 0.60 by Johnson and Asmundson (1957). McCartney (1961) estimated the heritability of body weight at 8, l6 and 24 weeks of age. These estimates averaged 0.68, 0.61 and 0.62, respec- tively, at the three ages. Nestor, 35 31. (1967) reported that the heritability estimates of body weights in turkeys were 0.44, 0.42 and 0.33 for 8, l6 and 24 weeks of age, respectively. Recently, Mahmoud (1966) studied the growth rate of Bobwhite quail and the relationship between the weight of a quail chick at hatching time and its subsequent weight up to 18 weeks of age. He re- ported that the size of the Bobwhite chick at hatching time influences its subsequent growth and there was a high correlation (0.7) between body weight of the Bobwhites at hatching time and at two weeks of age. That relation did not hold at four weeks of age but was again apparent by 16 weeks of age and was true for both sexes. High correlations were also noted between body weight at ten weeks of age and its subsequent growth. Similar correlations held true with respect to different sexes. He stated that the influence of body size of the Bobwhite quail chicks at hatching time on their subsequent growth should be of considerable importance from the standpoint of selection for rapid growth. Ideta and Siegel (1966), in chickens, estimated the phenotypic correlations between body weight at eight weeks of age and body weight at 24 and 38 weeks of age for the parental generation and subsequent generations up to the seventh filial. They found that the rate of in- crease per generation was 0.06 for the correlation between eight- and 24-week body weight and 0.08 for the correlation between eight- and 38-weeks body weight from parents to the seventh generation. It 13 started from 0.48 and increased gradually to 0.86 for 24-week body weight and from 0.33 to 0.78 for 38-week body weight from parental to seventh filial generation. Johnson and Asmundson (1957) reported a significant correlation between turkey body weight at eight weeks of age and body weight at 16 and 24 weeks of age for both male and female turkeys. It was approxi- mately 0.76 and 0.58 for 16 and 24 weeks of age, respectively. McCartney's estimates (1955) for body weight correlation in the turkey between 16 and 24 weeks of age were 0.74 for males and 0.72 for females, and his correlation estimates (1961) between turkey body weight at eight weeks of age and body weight at 16 and 24 weeks of age and between 16 and 24 weeks of age were 0.65, 0.57 and 0.79 for males and 0.73, 0.59 and 0.74 for females, respectively. The estimates for the same mentioned three ages were 0.76, 0.54 and 0.79, respectively, as made by Nestor et 31. (1967). These estimates for the three ages as calculated by different investigators were quite similar. Growth Rate and Body Weight Few reports could be located concerning body weight and growth rate of the Bobwhite quail during the growing period. It has received little or no attention from researchers in the past. Mahmoud (1966) calculated average Bobwhite weights from one-day- old up to 18 weeks of age. He reported that female Bobwhite quail grew faster than males and that they were heavier when they reached full body maturity. Baldini (1951) showed that Bobwhite quail gained weight rapidly up to eight weeks of age and had attained 73 percent of their adult 14 weight by that age. Mahmoud's results (1966) agreed to a great extent with those reported by Baldini. Asmundson and Lerner (1933) reported that Single Comb White Leg- horn male chicks grew more rapidly than the females and the earlier hatched chicks grew more rapidly than the later hatched chicks. These results point to the conclusion that there were genetic differences with respect to rate of growth; these differences were determined by multiple factors. Female turkeys are less variable than males in body weight. Sex difference of body weight in turkeys is influenced by heredity. The female body weights at 24 weeks of age were 58-65 percent as much as the male body weights (Asmundson, 1942; Knox and Marsden, 1944). Egg Production Information about egg production of Bobwhite quail is sparse. Nestler gt 31. (1944) reported that the best egg production, an average of 58 eggs per hen for the season of 168 days (34.5% egg production), was obtained from birds on a diet containing 23 percent protein. Similar results concerning egg production level of Bobwhite quail have been re- ported by Baldini gt 21. (1952). Mahmoud (1966) measured egg production of Bobwhite quail housed at several population densities for an experimental period of four months egg production. The average egg production was 0.10, 0.14, and 0.32 eggs/bird/day for a population density of 0.06, 0.12 and 0.24 square feet of floor space/bird, respectively, and under 16 hours of constant light per day. 15 The influence of light on egg production of Bobwhite quail has been studied by some investigators (Funk g£_al,, 1941; Kirkpatrick, 1955, 1964; and Robinson, 1963). Bobwhite quail could be stimulated by continuous light to reproduce during other than the normal season, and under these conditions Bobwhite quail attained sexual maturity as early as 139 days of age (Baldini £5 31., 1952). Mahmoud (1966) found that average age at sexual maturity calculated by the first egg produced was 118, 137, and 137.7 days for birds housed at 0.24, 0.12 and 0.06 square feet of floor space/bird density. More recently, daily egg production in Bobwhite quail was recorded by Kulenkamp and Coleman (1968) on two unselected groups over a period of more than two years. Peak production was reached between five and six months after the first egg was laid. First year survivor production for these birds averaged 165 and 179 eggs, respectively, for single females and for those paired with males, while the second year averages were 115 and 150 eggs for the two groups. Several females had records in excess of 200 eggs over a period of 365 days with one outstanding female having a record of 300 eggs. Mortality Information concerning mortality in Bobwhite quail is extremely limited in the literature. McNamara (1933) reported that mortality among Bobwhite quail to four weeks of age was between 16 and 20 percent. Nestler EE.§1' (1942) found after discussion with a number of reliable quail breeders that a 45 percent mortality to eight weeks of age was considered about average by many. EXPERIMENTAL PROCEDURE Stock Used Bobwhite quail used in all experiments were from stock which has been maintained as a closed flock by the Department of Poultry Science, Michigan State University for more than five years. Housing and Management Birds of the parental generation of the experimental Bobwhite quail were hatched on June 29, 1965. When they were twenty weeks of age and were approaching sexual maturity, at which time sex could be rather easily determined, 50 pairs were randomly selected and kept in modified individual handmade wire cages, each cage for one pair (male and female) of Bobwhite quail. Feed and water were kept before the birds at all times. There was no source of heat inside the cages, but the tempera- ture in the room where the cages were located was kept at approximately 75° F. by means of two central heating system lines and two installed air conditioners. The light was controlled automatically for 15.5 hours per day all the year round. The eggs were gathered and recorded daily, in the afternoon, for each pair of birds and were then kept at room temperature in egg-flat trays in the incubator room, and were set for incubation every two weeks. A quail breeder ration (Table 1) was fed throughout the experiment to the parental and the first filial generation birds. 16 17 TABLE l.--Composition of quail breeder ration Ingredients Percent of ration Ground yellow corn Soybean oil meal, dehulled, 50% protein Alfalfa meal, 17% protein Dried whey Meat and bone scraps, 50% protein Fish meal, menhaden, 60% protein Ground limestone (CaCo3) Dicalcium phosphate Salt, iodized Vitamin premix* Fat Total Calculated analysis: Protein Fat Fiber Calcium Phosphorus Productive energy, Cal./1b. 41.25 37.00 5.00 2.50 2.50 2.50 5.00 1.50 0.50 0.25 2.00 100.00 25.66 4.27 3.47 3.03 0.83 835.63 *Nopcosol M—4, Nopco Chemical Company, Harrison, New Jersey. 18 In this experiment lack of facilities and equipment designed for the purpose of keeping and raising Bobwhite quail made it essential in many instances to utilize equipment designed for chickens. Therefore, some inconvenience was noted because of the utilization of such equipment. Jar-type gravity-fed waterers designed for baby chicks were utilized for watering the quail during the first four weeks of their lives. Although a wire net-type cover was in the exposed part of the waterers to prevent newly hatched quail from drowning, a marked loss in birds from drowning was noted, especially in the first few days of the brooding period. Cellophane tape was used where applicable to prevent the young quail from getting out of the batteries and helped somewhat to overcome this problem. The equipment utilized was responsible for some of the mortality observed in this experiment, especially in the very young quail. Growing quail were housed in Petersime chick starting battery compartments, 39 x 27 x 9 inches. Adult quail were housed in welded-wire cages which were of two sizes; the type 1 cages, where 50 pairs of parental generation quail were kept during the egg production period, were 9 x 6 x 6.5 inches. The type 2 cages, in which 50 pairs of first filial generation Bobwhites were kept after they were 20 weeks of age, were 8 x 5 x 5 inches. Both sizes of cages had a sloping floor from back to front. Neither type 1 nor type 2 cages were provided with heat. Incubation For a total of six hatches, eggs that were to be incubated were gathered from the parental birds each afternoon, recorded and kept in egg-flat trays in the incubation room at room temperature until they 19 were placed in the incubator. They were candled to detect checks, and the sound eggs were set in cone-type egg—flats which were cut to fit into the regular setting trays of the Jamesway 252 incubators which were used for incubation in these experiments. Setting was done every two weeks. During the first 21 days of incubation the incubator was operated at a temperature of 99.0° to 99.5° F., dry bulb, and 86 to 87° F., wet bulb; on the let day of incubation the eggs were transferred to a hatcher and placed in wire pedigree baskets. Dividers were placed between eggs from each pair of parental quail. Therefore, the hatching eggs from each individual female were separated from those from all other females. The hatcher was operated at a temperature of 98.5 to 99.0° F., dry bulb, and 88.0 to 90.0° F., wet bulb. 0n the 24th day of incubation the newly hatched quail chicks were removed, wing-banded with small wing bands according to families, re— corded and placed in Petersime chick starting batteries at a density of about 100 chicks in each compartment. Chicks (first filial generation) were brooded in Petersime batteries in the same cage room where their parents were housed. Thus, insofar as possible, environmental conditions (light, rations, etc.) were the same for the parental and first filial generation Bobwhites. Growing and Breeder Quail In all hatches throughout the experiment, quail chicks were reared with paper covering the wire floor of the battery brooder for the first four weeks. This was done to prevent the feet of the chicks from being trapped, as the size of mesh of the wire making up the floors of the batteries in which they were brooded was not designed for baby quail. 20 At the end of four weeks, the paper was removed and the quail were dis- tributed at an average density of 40 to 50 birds per compartment and were kept in the batteries to 20 weeks of age. During brooding an attempt was made to provide equivalent heat for all groups. All groups received 15.5 hours of light per day (from 7:00 A.M. to 10:30 P.M. daily). The light bulbs inside the compartments of the batteries, which were located in the same areas as the heating elements and which were intended to indicate when the heating elements were operating, were taken out to reduce cannibalism and picking. A quail breeder ration (Table 1) was fed throughout all the experiment. This ration had been utilized for quail by the Michigan State University Poultry Science Department for several years and had proven to be adequate for all ages of Bobwhite quail. Mortality was recorded daily during the growing period (to 20 weeks of age). Weights of all surviving birds were taken at four weeks of age. Weights were taken again when the birds were eight weeks of age and at the end of each subsequent two-week period to twenty weeks of age.' All weights were taken to the nearest gram. All possible information con- cerning the weight of the birds which did not survive until the end of the experimental period was utilized; i.e., if a bird died at nine weeks of age, information concerning its weight at eight weeks of age was in- cluded in the data and so on. Individual records for each chick were established. Not until the quail were 15-16 weeks of age were they accurately sexed. Since sex could not be easily determined before 15-16 weeks of age, mortality with respect to sex prior to this age is not reported. 21 When the first filial generation of the experimental Bobwhites were 20 weeks of age, 50 pairs were randomly selected and kept in type 2 handmade wire cages, one pair (male and female) per cage. The eggs were gathered and recorded daily. Records Table 2 shows the number of P1 Bobwhite pairs and F1 in each of the six hatches, the hatching dates and the number of birds quail chicks alive at four and 20 weeks of age. The parental generation consisted of 50 pairs (male and female) of Bobwhites and the first filial generation of 985 Quail chicks at hatching time, 642 at four weeks of age and 585 Bobwhites at 20 weeks of age. Only 28 families from the P generation and their F offspring 1 1 were used for estimation of heritability and correlation for body weight, average body weight at different ages and the corresponding growth rate at those ages. Those families which produced more than two male and two female offspring were used. Mortality was recorded for the F genera- 1 tion from hatching time to 20 weeks of age. Nineteen Fl families and their daughters were used for egg production and heritability estimates of egg production. They were the only families which produced eggs during the recording period. Estimations and Statistical Procedures Heritability estimates of Bobwhite body weight, correlation co- efficients of body weights at different ages, average body weights, growth rates and mortality were calculated for 4, 8, 10, 12, l4, 16, 18 and 20 weeks of age. Egg production and heritability estimates of egg 22 TABLE 2.--Record of Bobwhite parental and first filial generation Number of birds Hatching @ hatching @ 4 @ 20 date time weeks weeks Parental genera- June 29, 1965 100 50 tion (P1) (50 prs.) prs. First filial gen- eration (Fl) Group 1 May 3, 1966 195 119 102 Group 2 June 21, 1966 212 175 159 Group 3 July 5, 1966 149 112 99 Group 4 Sept. 28, 1966 153 84 82 Group 5 Oct. 14, 1966 153 105 96 Group 6 Oct. 28, 1966 123 47 47 985 642 585 23 production were calculated for a six-month period from 12 to 18 months of age. Body weight and growth rate were calculated on all birds surviving to a given age. The growth rate was calculated on the basis of grams gained per bird per day and it was the average gain (grams) per bird per day during the interval between two successive weighings; the percent growth at any given age was calculated on the basis of 20-week body weight. Mortality was based on the number of Bobwhites at hatching time. The estimates of heritability for Bobwhite body weights were cal- culated by two methods (Lush, 1948): (1) from regression of offsprings on parents and (2) from variance components for full—sibs. The herita— bility estimates for egg production were calculated by the method of re— gression of F1 on Pl° 1. Regression method - By using the following formula to cal- culate the heritability estimate. Xxy — I§%X b: 2 where: b = regression coefficient, which is equivalent to the heri- tability estimate of combined sexes and half the estimate of the sex value (male or female). NF = number of families x = parent's individual weight (parental generation) y = offspring's average family weight (first filial generation) 24 Variance components method - The heritability estimates were calculated according to the following formula: 2 1/2 h2 = O F 2 O F + 0 e where: MS - MSE (Oze) 2 F O F - C1 SS F MSF ’ NF - 1 . 2 SS = Z-LEEL- - CF F n1 2 _ (GT) CF — ‘FF"' NF _ Zni Cl=__—__L_ NF — 1 MS (Oze) = SSE E (N-l) - NF - l SSE = SSy — CF SS = 2x2 - CF Y where: CF = Correction factor Cl = Coefficient 1 x = individual weight (F1) Ti = total weight of each family ni = number of each family GT grand total weight of all the birds NF = number of families N = total number of all the birds 25 The computer at Michigan State University was utilized and simple correlation coefficients were calculated for the body weight of Bobwhite quail at 4, 8, 10, 12, 14, 16, 18 and 20 weeks of age. The formula (Pearson product moment) used in these computations was (Ruble, Kiel and Rafter, 1966): N 2(xit - xi) (x,t - xj) rij _ Lt - l N - 2 2 2(x - xi (xjt — xj) RESULTS AND DISCUSSION Heritability Estimates for Body Weight As noted earlier, heritability estimates for body weights of Bob- white quail in the present experiment were calculated by two methods: (1) regression of offsprings on parents and (2) variance components of full-sibs. Regression method — The values of heritability estimates, calcu- lated by this method, of body weight for Bobwhite quail from four to 20 weeks of age are shown in Table 3. They are shown graphically in Figure 1. This illustrates the differences between males, females and combined sexes. In males, the heritability estimates for body weight from four to 20 weeks of age were in a range from -0.10 to 0.22 with an average of 0.03. The estimates for 10-, 12— and 14-week body weights were negative values (-0.06, -0.10 and -0.10, respectively). They were the lowest values among the heritability estimates. The highest male estimate was for 18-week body weight. In female Bobwhite quail, these estimates ranged from 0.08 to 0.52 with an average of 0.32. The lowest value was for four—week body weight and the highest for 14-week body weight. All female estimates were positive and were, in all cases, higher than those for male body weights at the corresponding ages. 26 27 TABLE 3.--Heritability estimates for body weight in Bobwhite quail from four to 20 weeks of age and for egg production from 12 to 18 months of age (regression method). Expected Age Male Female Combined (combined) 4 wks. 0.06 0.08 0.05 0.07 8 wks. 0.04 0.40 0.15 0.22 10 wks. -0.06 0.36 0.14 0.15 12 wks. -0.10 0.46 0.08 0.18 14 wks. -0.10 0.52 0.16 0.21 16 wks. 0.06 0.14 0.10 0.10 18 wks. 0.22 0.28 0.25 0.25 20 wks. 0.14 0.32 0.22 0.23 Average 0.03 0.32 0.14 0.18 Egg production 0.37 Heritability estimates 28 0.60 . __.. Combined sexes _._.. Females 0. 501i —--— Alales ./94 0. 40 . 0. 30 . 0. 20 . 0.10 . 0.00 . \\ \ -0.10 . \.__...../ 71 3 53 1'0 {2 I4 13 I8 50 Age of birds (weeks) Figure 1. Heritability estimates for body weight in Bobwhite quail from four to 20 weeks of age (regression method). 29 The lowest male and the highest female heritability estimates for body weight were those for l4—week-Old birds. Heritability estimates of body weight for the two sexes at 18 weeks of age were in close agreement (0.22 and 0.28 for male and female, respectively). In combined sexes, the lowest heritability estimate was 0.05 for four-week body weight and the highest was 0.25 for the 18-week body weight with an average of 0.14. All the estimates were higher than those of males and lower than those of females at the corresponding ages. The combined heritability estimates for 16-, 18- and 20-week body weights (0.10, 0.25 and 0.22, respectively) were in close agree- ment with those of the expected values at the corresponding ages. The average heritability estimates for Bobwhite body weights in the present experiment from four to 20 weeks of age were 0.03, 0.32 and 0.14 for male, female and combined sexes, respectively. The expected average body weight heritability estimate from four to 20 weeks of age, 0.18, was higher than that realized. Variance components method — The values of heritability estimates of Bobwhite body weights calculated by the method of variance components of full-sibs for the previously mentioned ages in the present experiment for the same birds are shown in Table 4. Figure 2 shows graphically the differences between male, female and mixed sexes as calculated by this method. In male Bobwhite quail, these estimates were in a range from 0.19 to 0.62 with an average of 0.47. The lowest value was for four-week body weight and the highest was for 14— and 16-week body weights. Heri— tability estimates for Bobwhite male body weights were positive values. 30 TABLE 4.-—Heritability estimates for body weight in Bobwhite quail from four to 20 weeks of age (variance components method) Expected Age Male Female Combined (combined) 4 wks. 0.19 0.40 0.32 0.30 8 wks. 0.26 0.26 0.26 0.26 10 wks. 0.46 0.46 0.44 0.46 12 wks. 0.54 0.48 0.48 0.51 14 wks. 0.62 0.48 0.52 0.55 16 wks. 0.62 0.44 0.54 0.53 18 wks. 0.56 0.52 0.52 0.54 20 wks. 0.54 0.32 0.44 0.43 Average 0.47 0.42 0.43 0.45 Heritability estimates .70 31 —— Combined ———- Males —-—-— Females 16 12 i4 I6 133 27) Age of birds (weeks) Figure 2. Heritability estimates for body weight in Bobwhite quail from four to 20 weeks of age (variance components method). 5" O on 32 In females, the lowest estimate was 0.26 for eight-week body weight and the highest was 0.52 for 18—week body weight with an average at 0.42. In combined estimates, the average was 0.43 with a range from 0.26 for eight—week body weights to 0.54 for l6-week body weights. The combined heritability estimates rather closely agreed with the expected values at all corresponding ages. All the heritability estimates of Bobwhite body weights calcu- lated by variance components were positive values. For 4-week body weight, male heritability estimates were lower than those for female, but for 12— to 20-week body weight male estimates were higher than those for females. All the combined estimates were between male and female estimates of the corresponding ages except at 10 weeks of age where the combined estimate was 0.44 whereas both the male and female estimates were 0.46. Generally, the estimates computed by the variance components method were somewhat larger than those estimates computed by the regres- sion method at the corresponding ages. The average estimates by variance components methods were 0.47, 0.42 and 0.43 and those by the regression method were 0.03, 0.32 and 0.14 for Bobwhite males, females and com- bined sexes, respectively. The lowest body weight heritability estimate was -0.10 (regression) and the highest was 0.62 (variance components). Both were for 14-week-old male Bobwhites. The possibility of having these differences between the two methods used in computing heritability estimates of Bobwhite body weight may be due to the following: 1. Sampling errors. 2. Dominance plus fractions of epistatic components. 33 3. Maternal effects. 4. Sex-linked effects. Lerner (1958) stated that the heritability of a given trait may differ from one population to another, or vary in the same population at different times, and that this should not occasion any surprise. He stated further that it is not easy to determine the cause of dif- ferences. From the extensive data which were mentioned previously in the review of literature, not all of the heritability estimate figures cited by the workers are comparable. Various techniques were used in the different studies and several methods of estimations were employed. Heritability estimates from variance components for Japanese quail body weight at four weeks of age were 0.59 and 0.47 for males and females, respectively (Yoshida and Collins, 1967), and were in rather close agreement with those computed for 14-week-old Bobwhite quail in the present experiment (0.62 and 0.48 for males and females, respec— tively). Heritability estimates from variance components for Bobwhite quail body weights (combined estimates) in the present experiment aver- aged 0.43 and ranged from 0.26 to 0.54. In chickens, Siegel (1962) made a summary of 176 published heritability estimates for body weight and found that the median heritability estimate was 0.41 with an inter- quartile range of 0.29 to 0.54. In turkeys, the average was 0.52 with a range of 0.33 to 0.68 (Abplanalp and Kosin, 1952; Goodman gt_gl,, 1954; Bumgardner and Shaffner, 1954; McCartney, 1955 and 1961; Johnson and Asmundson, 1957; and Nestor £3 31., 1967). From the present study it appears that the Bobwhite quail body weight heritability estimates 34 computed by the variance components method are in agreement with those previously reported for chickens, turkeys and Japanese quail. Therefore, these heritability estimates of Bobwhite quail body weights are in a range of moderate to high. Results from computation of heritability estimates by the variance components method indicate that selection of Bobwhite quail breeders for body weight could be practiced on an individual basis from 10 to 20 weeks of age as a useful tool for influencing this character in breeding stock. Results from computation of heritability estimates by the regres- sion method indicate that selection of individual Bobwhite quail breeders for this character could be successfully practiced from 16 to 20 weeks of age. It was mentioned previously that the differentiation between sexes in Bobwhite quail is difficult to detect before the birds are 16 weeks of age. From this, and from the fact that heritability estimates of body weight in both sexes are highest between 16 and 20 weeks of age, it appears that selection of Bobwhite breeders on the basis of body weight within a given sex would be most practical from 16 to 20 weeks of age in either sex, without regard to the way of computing the herita- bility and it will be possible to forecast the amount of improvement expected. Probably, the most practical time for selection would be at 18 weeks of age. Since at this age Bobwhite quail can be sexed with 100 percent accuracy on basis of external appearances. Heritability Estimates for Egg Production The heritability estimate of Bobwhite quail egg production for the six-month period from 12 to 18 months of age, calculated by the 35 method of regression of offsprings on parents, is shown in Table 3. The estimate was 0.37. From a review of literature, no documented reports could be located concerning heritability estimates for egg production in Bobwhite quail; however, several investigators reported estimates for chickens (Lerner and Cruden, 1948; King and Henderson, 1954; Waring g£_al,, 1962; Jaffe, 1966; Amer, 1967; and Kinney gt 31., 1968). These heritability estimates for egg production in chickens averaged 0.23, with a range from 0.13 to 0.33, which was lower than that for the Bobwhite quail in the present experiment. Based on the results of these experiments, it appears that egg production in Bobwhite quail is a positively heritable trait. This means that selection of breeders based upon individual egg production records should lead to rapid improvement in egg production in Bobwhite quail. This information should be of value to Bobwhite quail breeders who desire to improve reproductive capacity of their stocks and to forecast the amount of improvement. Correlation Coefficients of Body Weights In Tables 5, 6 and 7 are shown all the possible 96 correlations between body weights in the Bobwhite quail in this experiment for male, female and combined sexes from four to 20 weeks of age. All body weight correlations were positive values and were significant at the 0.05 level (a = 0.05). Sixty-nine body weight correlation coefficients out of 84 correlated values were highly significant at the 0.01 level (a = 0.01). These correlations were within a range from 0.38 to 0.99. 36 .Aao.o u av Ha>aH Ho.o was an uaausmfiamwmee .Amo.o u do Ha>mH mo.o and um uaauncwamame .uB .us .us .mxz om .mxs ma .mxs 0H m m o oo.H no.0«s em.o«« oo.H om.os« oo.H .u3 .axz ea m oa.o** Hm.0k« qm.o«« oo.H 0“; .mx3 NH q No.0ks em.o«« mm.o«« mo.o«« oo.H .u3 .axs OH qw.oa« ow.o«a mm.os« ww.o«« mm.o«« oo.H .u3 .mxs w mm.o«s Ho.o«« mo.os« No.0ss mo.osk em.oa« oo.H tug .mxz q Nq.o« Hq.o« He.0k mm.o« Ne.oa no.0ks mm.o«« oo.H nus Qua 0U3 ou3 .u3 Qua Gus U3 .mxa om .axa ma .mxs as .mxs as .mxs NH .mxs OH .mxs m .mxs q Omm wo mxoos om ou snow Eoum moama ouwnznom 6H unwfims moon mo moumEaumo coaumaouuoo O£H11.m mqmaH Ho.o one am usaOHHHameee .Amo.o n av HO>OH mo.o mnu um uumOHmwames oua .mxz ON a oo.H oug .mxB ma Hm.o«« oo.H OUB .mxa 0H mw.o«k om.o«k oo.H oUB .mxa «H m mm.0k« ow.o«s c¢.0k« oo.H a“; .mi3 NH q mm.os« ww.oa« mm.oss mm.o«« oo.H ou3 .mxs OH qw.oa« om.o«s mm.o«« om.os« cm.os« oo.H a“; .mx3 m wo.o«« oo.o«« mm.o«« me.oa« «n.0«k mm.os« oo.H Qua .mxB q Nq.o« qq.o« mq.os oq.0k mq.o« Hm.o«« wo.o«« oo.H oUB 00.3 ouz ou3 OUB 0U3 0“; .m33 0H .mas mH .axa 0H .mxa «H .mxa NH .mxs OH .mxB w .mxs q mwm mo mxom3 om ou “sow Eoum wOHmEOw muws3nom ow unwfioa upon mo mommafiuwo coaumamuuoo oshll.o mqmOH Ho.o onu um ucmOHchmesa .Hmo.o 1 av Ha>aH mo.o was as SeaOHHHamea .u3 .u3 .us .uB .uz .u3 .u3 .u3 .mx3 om .mxs wH .mxs 0H .m&3 «H .m&3 NH .mxz OH .mxz w .mxz e w n o m q m N H oo.H mm.os« oa.os« mm.o«« qm.o«k mm.o«k cm.o«« wq.o« .uB .mxs om oo.H mm.o«« qm.oss om.osk om.o«« o~.o«« mq.o« .uB .mx3 wH oo.H no.0«k mm.0k« mm.o*« mm.o«k «c.0k .u3 .m&3 0H oo.H mm.os« mm.o«« no.0«k mm.o« .us .mx3 «H oo.H m¢.o«« mm.o«« Nq.o« .us .mxz NH oo.H ow.o«« mm.o«« .u3 .m&3 CH oo.H ow.os« .uB .mxB w oo.H .ua .mx3 q owe mo mxoms ON ou know Eoum moxmm poaHnEoo ouHcanom CH uszoz anon mo moumsHumo GOHOMHOHHOO m:H11.n MHm¢H 39 In Figures 3, 4 and 5 are shown graphically the correlations be- tween body weights in Bobwhites for male, female and combined sexes from four to 20 weeks of age. Correlation coefficients between body weights were increased according to time and age, i.e. correlations between four week body weights and subsequent weights were lower than those between eight week body weights and subsequent weights, correlations between eight week body weights and subsequent weights were lower than those between 10- week body weights and subsequent weights, and so on. The lowest correlation coefficients among Bobwhite body weights were 0.38, 0.39 and 0.40; these were the correlations between four and 14-week body weights for combined sexes, males and females, respectively. However, even these correlations were significant at the 0.05 level (a = 0.05). The only documented report which could be located in the litera- ture concerning correlation in Bobwhite quail for body weight was that of Mahmoud (1966). He calculated the correlation between body weight in Bobwhite quail at hatching time and their growth to 18 weeks of age. He reported that there was a relationship between body weight at hatching time and that at two weeks of age. That relation did not hold at four weeks of age but was again apparent by 16 weeks of age and was true for both sexes. A high correlation was also noted in his study between body weight at ten weeks of age and the weight of birds to 18 weeks of age. He found that the correlation coefficients between body weight at hatching time and subsequent weights were within a range of -0.18 to 0.71. His correlation values were in general lower than those values computed in the present experiment; he reported some negative Correlation estimates 40 '8 '93 a A O A Figure 3. 8 10 12 14 16 18 20 Age of birds (weeks) Correlations of body weight in Bobwhite males from four to 20 weeks of age. (Points at ages on each line represent correlation with weight at first age shown on that particular line.) Correlation estimates 8 '8 a '3 41 N v ' I 4 6 8 10 12 14 16 18 20 Age of birds (weeks) Figure 4. Correlations of body weight in Bobwhite males from four to 20 weeks of age. (Points at ages on each line represent correlation with weight at first age shown on that particular line.) Correlation estimates 1.“) 42 111 1'2 1'4 1'6 15 21') Age of birds (weeks) Figure 5. Correlations of body weight in Bobwhite combined sexes from four to 20 weeks of age. (Points at ages on each line represent correla- tion with weight at first age shown on that particular line.) 5.1 0: mu illlllllllllllllll lllllll 43 correlations and some uncorrelated weights while in this experiment all the correlations were positively significant. From a review of literature relatively few correlations have been reported concerning body weights of chickens and turkeys (Ideta and Siegel, 1966; Johnson and Asmundson, 1957; McCartney, 1955 and 1961 and Nestor §£_§l,, 1967). Eight-week body weights were consistently cor— related with subsequent weights and were used as a selection index for both chicken and turkey breeders. In the present investigation, Bob- white quail body weights were also consistently correlated with subse— quent weights; and could, therefore, be used as a selected index in breeding for improvement of Bobwhite quail body weight. Growth Rate and Body Weight From a review of literature, few reports could be located con- cerning growth rate and body weight in Bobwhites during the growing period (Baldini, 1951; Mahmoud, 1966). In Table 8 is shown average body weights and growth rates for male, female and combined sexes of first filial generation Bobwhite quail from four to 20 weeks of age. In Table 9 can be found the same information for the parental generation. In Figure 6 is graphically shown the average body weights of first filial generation Bobwhite quail from four to 20 weeks of age. In Figure 7 is shown graphically the same information for the parental generation. The comparisons of parental and first filial generation Bobwhite quail body weights for combined sexes from four to 20 weeks of age are demonstrated in Figure 8. The asymmetrical sigmoid curve reflects the growth responses in Bobwhites as well as in most vertebrate species. 44 TABLE 8.--Average body weight (grams) and growth rate (grams gain/bird/ day) of first filial generation of Bobwhite quail from four to 20 weeks of age (growing period). Male Female Combined Age A.B.W. G.R. A.B.W. G.R. A.B.W. G.R. % growth 4 wks. 56.4 58.6 57.5 31.0 8 wks. 135.0 2.80 135.1 2.73 135.0 2.76 72.9 10 wks. 158.4 1.66 156.2 1.51 157.3 1.58 84.9 12 wks. 169.4 0.78 166.9 0.77 168.1 0.77 90.7 14 wks. 175.2 0.39 172.6 0.41 173.8 0.40 93.8 16 wks. 180.3 0.35 177.7 0.36 179.0 0.36 96.6 18 wks. 182.3 0.15 180.6 0.18 181.4 0.16 97.9 20 wks. 185.5 0.23 185.1 0.31 185.3 0.27 100.0 . Growth rate was calculated on all birds surviving to a given age. . Percent growth was calculated on 20—week body weight basis. . A.B.W. = Average body weight. G.R. = Growth rate. le—l Average body weight (grams) 45 Combined sexes .100 _..__ Females P 90 160 . . 80 140 . . 70 120 1 D m 100 . » 50 so . . 40 60 l .30 q d :1 6 8 13 1'2 1'4 1'6 1'6 20 Age of birds (weeks) Figure 6. Average body weights of first illial generation Bobwhite quail from four to 20 weeks of age (growing period). Percent body weight (20-week body weight basis) 46 TABLE 9.--Average body weight (grams) and growth rate (grams gain/bird/ day) of parental generation Bobwhite quail from four to 20 weeks of age (growing period). Male Female Combined Age A.B.W. G.R. A.B.W. G.R. A.B.W. G.R. % growth 4 wks. 62.5 64.3 63.4 34.6 8 wks. 137.1 2.67 135.5 2.55 136.3 2.61 74.3 10 wks. 158.4 1.52 154.9 1.38 156.7 1.45 85.4 12 wks. 169.4 0.78 165.8 0.78 167.6 0.78 91.4 14 wks. 174.8 0.39 172.2 0.46 173.5 0.43 94.6 16 wks. 182.6 0.55 178.9 0.48 180.7 0.52 98.5 18 wks. 181.9 -0.05 177.1 -0.12 179.6 —0.09 97.9 20 wks. 185.9 0.29 180.1 0.27 183.4 0.28 100.0 N.B. 1. Growth rate was calculated on all birds surviving to given ages. 2. Percent growth was calculated on 20-week body weight basis. 3. A.B.W. = Average body weight. G.R. = Growth rate. Average body weight (grams) 180 160 140 120 100 47 Combined sexes ‘o ———- Niales / ’. _._.._ Females r I Ti I l I fl I I 4 6 8 10 12 14 16 18 20 Age of birds (weeks) Figure 7. Average body weight of parental generation Bobwhite quail from four to 20 weeks of age (growing period). Average body weight (grams) 48 — Parental generation 180 . _-_-- First filial generation ..-—-—’ 160 .. 140 - 120 . 100 H 80 . 60 . 4 6 8 H) w1'2 1'4 1'6 1'8 20 Age of birds (weeks) Figure 8. Comparison of body weight of combined sexes in parental and first filial generation Bobwhite quail from four to ~20 weeks of age. 49 In the first filial generation at four weeks of age, average body weight of female Bobwhite quail was slightly more than that of males (58.6 and 56.4 grams, respectively). At eight weeks of age, average weights of the two sexes were rather close (135.0 and 135.1 grams for males and females respectively). At ten weeks of age average male weights were slightly more than those of females (158.4 and 156.2 grams for male and female, respectively). This trend continued through the twentieth week of age at which time average weights were 185.5 and 185.1 grams for male and female Bobwhites, respectively. The average parental and the first filial Bobwhite body weights were in close agreement to one other at any given age. Body weights in the parental generation Bobwhite quail followed almost the same pattern as that in the first filial generation except that males were slightly heavier than females at eight weeks of age. At four weeks of age the average weights were 62.5 and 64.3 grams and at eight weeks of age they were 137.1 and 135.5 grams for male and females, respectively. The males were heavier than females at each subsequent weighing including that at 20 weeks of age at which time average weights were 185.9 and 180.1 grams for males and females, respectively. These results do not agree with the observations of Stoddard (1931) and Mahmoud (1966) who reported that female Bobwhite quail grew more rapidly than did males. A number of investigators have reported that body weights of mature Bobwhite quail females tend to be heavier than those of mature males (Stoddard, 1931; Aldrich, 1946; Nestler, 1949; Baldini, 1951; Baldini gt 21., 1952; Ripley, 1960; and Mahmoud, 1966). This may be due to egg production and to fat deposition in various tissues of the female body. 50 The average body weight of Bobwhite males reported by Mahmoud (1966, Appendix 1) were at all corresponding ages lower than the average Bobwhite male body weights reported in the present experiment. They increased from 49.1 to 179.9 grams from four to 18 weeks of age, com- pared to 56.4 to 182.3 grams for the same ages in the present experiment. Female average body weight in Mahmoud's experiment started lower and ended higher than in the present experiment. He recorded an increase from 45.9 to 187.9 grams from four to 18 weeks of age, compared to 58.6 to 180.6 grams in the present experiment. In respect to growth rate (grams gain per bird per day), the highest growth rate for both the parental and first filial generation of Bobwhite quail was recorded for the period between four and eight weeks of age. The average gain for the combined sexes during this period was 2.61 and 2.76 grams gain per bird per day for P1 and F1 generations, respectively. The rate of growth declined gradually with time and age of bird from four to 18 weeks of age. In both generations the lowest growth rate occurred between 16 and 18 weeks of age (-0.09 and 0.16 grams gain per bird per day for parental and first filial genera- tions, respectively). From 18 to 20 weeks of age growth rates were higher than those from 16 to 18 weeks of age, but they were still lower than the growth rates of previous ages. The decrease in the rate of growth may indicate that both male and female birds between 18 and 20 weeks of age were approaching mature body weight. In the present experiment Bobwhites gain weight rapidly to eight weeks of age. The parental generation birds had attained 74.3 percent and the first filial generation birds had attained 72.9 percent of 51 their 20-week body weight by that age. These results agree to a great extent with those reported by Baldini (1951) and by Mahmoud (1966). Egg Production ' Values for egg production of parental and first filial Bobwhite females for the six—month egg production period from 12 to 18 months of age and percent hen-day egg production are shown in Table 10. The average egg production per bird for the six—month period was 105.5 and 109.2 eggs and the percent hen—day egg production was 61.1 and 61.4 percent for P1 and F1 Bobwhite females, respectively. More than half of the females in the two generations had records in excess of 100 eggs each over a period of six months with five of them laying in excess of 150 eggs and two outstanding F females making records of 160 and l 161 eggs. From this investigation it appears that individual egg production records could be used as a useful index for selection of breeding stock by quail breeders. Mortality Mortality in the first filial generation Bobwhites from hatching time to 20 weeks of age is shown in Table 11. There were 985 Bobwhite chicks at hatching time and only 642 survived to four weeks of age. At 20 weeks of age the number alive was 585 birds. Mortality to four weeks of age was 34.8 percent. It was only 5.8 percent for the period from four to 20 weeks of age. The total percent mortality from hatching time to 20 weeks of age (growing period) was 40.6 percent calculated on the basis of total birds at hatching time. 52 TABLE 10.-—Egg production of parental and first filial generation Bob- white quail from 12 to 18 months of age (six-month period). Parental generation First filial generation Family Eggs % hen-day Eggs (no.) % hen—day no. (no.) egg prod. (Ave.) egg prod. l 73 40.6 60 33.3 2 110 61.1 160 88.9 3 88 58.7 115 63.9 4 83 46.1 90 49.7 5 93 51.7 110 61.1 6 86 47.8 93 51.7 7 123 68.3 105 64.5 8 65 36.1 110 61.1 9 130 72.2 92 50.9 10 41 58.6 156 86.7 11 95 52.8 100 55.6 12 110 61.1 116 64.4 13 107 59.4 112 62.2 14 109 60.6 139 77.0 15 122 67.8 94 52.2 16 146 81.1 161 89.4 17 151 83.8 136 75.6 18 118 65.5 80 44.6 19 154 85.6 45 25.0 Total 2004 2074 % hen—day egg prod. 61.1 61.4 Six-month egg prod./bird 105.5 109.2 53 TABLE ll.-—Morta1ity of first filial generation Bobwhites from hatching time to 20 weeks of age (growing period).* Mortality Accumulated mortality Birds Age (no.) No. % No. % Hatching 985 time 4 wks. 642 343 34.82 343 34.82 8 wks. 618 24 2.44 367 37.26 10 wks. 610 8 0.81 375 38.07 12 wks. 601 9 0.91 384 38.98 14 wks. 594 7 0.71 391 39.69 16 wks. 589 5 0.51 396 40.20 18 wks. 585 4 0.40 400 40.60 20 wks. 585 0 0.00 400 40.60 4-20 wks. 57 5.78 Total 400 40.60 400 40.60 *Percent mortality was calculated based on the number of birds at hatching time. 54 As noted, the highest mortality in the present experiment was recorded during the first four weeks of age with gradual declinations as the birds grew older. Mortality was 2.4 percent for the period between four and eight weeks of age and decreased to a point where no mortality was recorded between 18 and 20 weeks of age (Figure 9). Known and possible causes of mortality included infections, changes in battery temperature, feeding and watering problems, drowning, density of birds, birds putting their heads in between the wire net, seasonal changes resulting in high or low temperatures, picking and cannibalism during the early life (the author observed many serious incidences among the young Bobwhites in some of the hatched groups in spite of adequate food and water), and using equipment designed for chickens rather than for Bobwhites. Percent mortality Cu O N O 10 55 0 2 4 6 8 10 12 14 16 18 20 Age of birds (weeks) Figure 9. Mortality Of first filial generation Bobwhite quail from hatching time to 20 weeks of age. SUMMARY AND CONCLUSIONS Experiments were conducted to determine a number of parameters in Bobwhite quail. These parameters included heritability estimates for body weight, correlation coefficients of body weight, average body weight, growth rate and mortality during the growing period at 4, 8, 10, 12, 14, 16, 18 and 20 weeks of age in males, females and combined sexes; heri- tability estimates for egg production and percent hen-day egg production for a six-month period from 12 to 18 months of age. Heritability estimates for Bobwhite quail body weights were cal— culated by two methods: (1) regression of offsprings on parents and (2) variance components of full sibs. By regression, heritability estimates of body weight of Bobwhite quail from four to 20 weeks of age ranged from -0.10 to 0.22, from 0.08 to 0.52 and from 0.05 to 0.25 with an average of 0.03, 0.32 and 0.14 for males, females and combined sexes, respectively. The expected average for combined sexes (0.18) was higher than that realized. Female esti- mates were consistently higher than those of males at the corresponding ages. By variance components, heritability estimates of body weight of Bobwhite quail at the above mentioned ages were in a range from 0.19 to 0.62, from 0.26 to 0.52 and from 0.26 to 0.54 with an average of 0.47, 0.42 and 0.43 for males, females and combined sexes, respectively. The 56 57 expected values were in rather close agreement with those of the combined estimates. All the estimates were positive values. Differences in heritability estimates computed by the two methods are possibly due to sampling errors, dominance, maternal effects and/or sex-linkage. It appears that selection of Bobwhite quail breeders on the basis of body weight would be most effective when the quail are from 16 to 20 weeks of age with best results at 18 weeks of age without regard to the method of computing the heritability estimate or to sex of birds. At 18 weeks of age Bobwhite quail can be sexed with 100 percent accuracy on basis of external appearances. It should be possible to forecast the amount of improvement expected in body weight of succeeding generations of growing quail. The heritability estimate for egg production computed by the re- gression method for the six—month period from 12 to 18 months of age was 0.37. It appears that egg production in Bobwhite quail is a moderately heritable trait. It should be possible to forecast the amount of improvement in succeeding generations when selection of breeders is based upon egg production records. Correlation between four-week body weight and subsequent weights to 20 weeks of age in Bobwhite quail were in a range from 0.38 to 0.80. All the possible correlations of body weight between the different ages were in a range from 0.38 to 0.99 and were significant at the 0.05 level (a = 0.05), while 69 out of the 84 possible correlations were significant at the 0.01 level (a = 0.01). Bobwhite quail body weights were consistently correlated with subsequent weights at different ages; therefore body weight records at 58 four weeks of age or any subsequent age during the growing period could be used as a selected index for improvement in this character. Bobwhite quail chicks in the parental and first filial generation gained weight rapidly to eight weeks of age and had attained 74.3 and 72.9 percent of their adult weight by that age, respectively. The best growth rate during the growing period was between four and eight weeks of age. At very early ages the females were heavier than the males; however, at ten weeks of age the males were heavier than the females, a position which they maintained to 20 weeks of age. Body weights of parental and first filial generation Bobwhite quail were in close agree- ment at corresponding ages during the growing period. From a practical point of view Bobwhite quail body weight measure- ments could be a useful index in quail breeding and would be an effec- tive tool for selection and improvement. Selection could be practiced at an early age or at any age during the growing period. The average egg production in Bobwhites for a six month period from 12 to 18 months of age was 105.5 and 109.2 and the percent hen-day egg production was 61.1 and 61.4 for the P1 and F1 generations, respec- tively. It appears that individual egg production records could be a useful index for selection of breeders. Mortality in Bobwhites was inversely proportional to age. The highest mortality (34.8 percent) was recorded during the first four weeks of age. Mbrtality was only 5.8 percent for the period between four and 20 weeks of age and was 0.0 percent between 18 and 20 weeks of age. LI TERATURE CITED LITERATURE CITED Abplanalp, H. and I. L. Kosin, 1952. Heritability of body measurements in turkeys. Poultry Sci. 31:781—791. 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Eighth International Cong. Genetics:356—375. Lush, J. L., 1956. Animal Breeding_Plans. Iowa State College Press, Ames, Iowa. Mahmoud, T. H. H., 1966. Growth and reproduction of Bobwhite quail raised in confinement. Ph.D. Thesis, Michigan State University, East Lansing, Michigan. Marks, H. L. and T. B. Kinney, Jr., 1964. Estimates of some genetic parameters in Coturnix quail. Poultry Sci. 43:1338. Marks, H. L. and P. D. Lepore, 1968. Growth rate inheritance in Japanese quail. 2. Early responses to selection under different nutritional environment. Poultry Sci. 47:1540-1547. 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 conformations in a random-bred pOpulation of turkeys. Poultry Sci. 40:1694-1700. McNamara, L. G., 1933. Recent advances in quail breeding. Trans. of 20th Amer. Game Conf.:l92-198. Moyer, S. E., W. M. Collins and W. C. Skoglund, 1962. Heritability of body weight at three ages in cross-bred broiler chickens, re- sulting from two systems of breeding. Poultry Sci. 41:1324-1382. Nestler, R. B., 1949. Nutrition of Bobwhite quail. J. Wild. Mgt. 13:342-358. Nestler, R. B., W. W. Baily and H. E. McClure, 1942. Protein requirements of Bobwhite chicks for survival, growth and efficiency of feed utilization. J. Wild. Mgt. 6:185-193. Nestler, R. B., L. M. Llewellyn and M. Y. Berner, 1944. War-time diets for growing Bobwhite quail. J. Wild. Mgt. 8:221-228. 62 Nestor, K. E., M. G. McCartney and W. R. Harvey, 1967. Genetics of growth and reproduction in turkeys. 1. Genetic and non-genetic variation in body weight measurements. Poultry Sci. 46:1374-1384. Ripley, T. H., 1960. Weights of Massachusetts quail and comparisons with other geographic samples for taxonomic significance. Auk 77:445. Robinson, T. S., 1963. Egg production by Bobwhites under a fifteen-hour photoperiod. J. Wild. Mgt. 27:217-220. Ruble, W. L., D. F. Kiel and M. E. Rafter, 1966. Calculation of basic statistics on bastat routine. Michigan State University, East Lansing, Michigan. Stat. Series Description No. 5. Shaklee, W. E., C. W. Know and S. J. Marsdon, 1952. Inheritance of the sex difference of body weight in turkeys. Poultry Sci. 31:822-825. Shoffner, R. N., 1946. The heritability of egg production. Poultry Sci. 25:412. Siegel, P. B., 1962. Selection for body weight at eight weeks of age. Short term response and heritability. Poultry Sci. 41:954-962. Siegel, P. B., 1963. Selection for body weight at eight weeks of age. 1. Correlated responses of feathering, body weight and repro- ductive characteristics. Poultry Sci. 42:896-905. Siegel, P. B., 1963. Selection for breast angle at eight weeks of age. 2. Correlated responses of feathering, body weight and repro- ductive characters. Poultry Sci. 42:437-449. Stoddard, H. I., 1931. The Bobwhite Quail,gits Habits, Preservations and Increase. Charles Scribner's Sons, New York. Waring, F. J., P. Hunton and A. E. Maddison, 1962. Genetics of a closed poultry flock. British Poultry Sci. 3:151-160. Wyatt, A. J., 1954. Genetic variation and covariation in egg production and other traits in chickens. Poultry Sci. 33:1266-1274. 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. APPENDIX APPENDIX 1.--Mean body weights of Bobwhite quail from one-day-old to 18 weeks of age. (Mahmoud, 1966) Male Female Mixed sexes Age (ng) (31118) (21%) One-day-old 6.2 6.4 6.3 2 weeks old 18.7 18.5 19.1 4 weeks old 49.1 45.9 48.5 6 weeks old 91.7 86.3 90.7 8 weeks old 117.3 114.9 116.5 10 weeks old 135.9 160.4 147.5 12 weeks old 159.7 170.5 164.9 14 weeks old 168.7 176.2 172.1 16 weeks old 174.1 180.2 177.1 18 weeks old 179.9 187.9 184.0 63 MICHIGAN srnre UNIV. LIBRRRIES ill"WillillliIll(HillIlllllllllllllllllllIllllillllillil 31293011065897