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1. A total of 3236 females from eight meat‐type strains, half of which were vaccinated for Marek's disease (MD), and 11,193 Leghorn females from ten strains, all vaccinated for MD, were adventitiously exposed to MD and lymphoid leukosis (LL) viruses and observed to 392 and 497 d of age, respectively. 2. In the meat‐type birds, vaccination reduced total mortality from 43.4% to 27.1% and mortality due to MD from 16.4% to 5.4% but did not affect mortality and LL (2.9% and 3.4%). 3. In the vaccinated Leghorns total mortality was 11 %, including 2.1% from MD and 1.2% from LL. 4. Significant differences between strains of chickens were found in total mortality, as well as in MD and LL mortality. 5. Strain by vaccination interaction was observed in total rearing and adult mortality, as well as in the MD mortality of adult meat‐type females. 6. Leghorn strains with higher rate of egg production and meat‐type strains with lower growth rate tended to have better viability.

1. Genetic parameters and responses to selection involving egg composition and allied traits were estimated, using two unselected control strains and three selected strains of White Leghorns. 2. Heritability estimate for yolk weight was 0.5 ± 0.1; for albumen percentage protein, 0.6 ± 0.1; and for yolk percentage solids, 0.5 ± 0.1. 3. Genetic correlation estimates indicated that there was no antagonistic relationship between the weight of any egg component and its composition but, because of the unreliability of the estimates of the genetic correlations involving the egg number traits, it is impossible to predict the correlated effects that selection for egg composition would have on egg number. 4. Eggs from selected strains weighed an average of 3‐. g more, contained more albumen, and greater amounts of albumen percentage solids and percentage protein than controls, whereas no differences were found for yolk weight; yolk percentage solids changed little in the selected strains. 5. Comparisons of one cont...

The genotypes at a serum esterase locus were determined for 3208 female meat-type chickens. These birds belonged to three generations of six strains on which records of body-weight and reproduction traits were kept. Allelic frequencies among strains were compared and then a study was made of the relationship between esterase genotype and the following traits: body weight at five ages, age at first egg, survivor egg production, rate of egg production (%), egg weight, fertility and hatchability. Allelic frequencies did not differ in two of three years between replicate control strains but were significantly different in seven of nine comparisons between selected and control strains. Analysis of variance of paired comparisons of genotypes on a within dam family basis revealed only five of the 106 comparisons to be significant. No heterotic effects were indicated. It was concluded that the esterase genotypes studied do not have a major influence on the traits investigated.

INTRODUCTION THERE has been a renewed interest in recent years in Canada and the United States in the domestic goose as a meat bird, particularly as a meat bird that can obtain a large part of its food from pasture. Interest in the goose has also increased with the discovery that geese can be used very efficiently to control weeds in such crops as strawberries and cotton. However, anyone interested in goose breeding on a commercial basis will find very little information in the scientific literature which would be of value in developing a breeding program on a sound genetic and economic basis. As far as the authors are aware, there has been no experimental work reported on geese in which the trap-nest has been employed to obtain both individual and pedigree records for egg production, fertility and hatchability. There is practically no genetic information on these important economic traits …

Floor-reared broilers fed a broiler ration in pellet form were heavier at all ages (6, 9, 10 and 11 weeks) than birds fed the same ration in mash form. The percentage difference in weight between mash and pellet-fed birds increased to a maximum at 11 weeks for males and at 10 weeks for females. Four different genotypes (broiler strains) all showed a growth response to pellets although there was some evidence of a differential response.Coefficients of variation of body weight were higher at all ages for pellet-fed birds of both sexes. Females generally had higher coefficients of variation than males of comparable age on the same form of feed. For both sexes there was a slight tendency toward lower coefficients of variation with age. The data also indicated that, on both mash and pellets, separate rearing of the sexes resulted in greater variability than rearing the sexes together. There were, however, no differences in body weight due to the method of rearing the sexes. Among pellet-fed birds there was a greater incidence of breast blisters and incomplete back-feathering and the latter resulted in down-grading for dressing. Pellet-fed birds however graded higher for fat.

The correlated responses in egg quality traits to selection for high early body weight were studied in seven meat-type populations comprising five selected and two control lines. Traits studied were specific gravity, egg weight, albumen height, Haugh units, shell color, egg shape, shell roughness, wrinkling and asymmetry, and incidence of blood spots, meat spots and double yolks. Significant (P

Data from 14 egg production experiments, which had replicated pens and individual trapnest records, were analysed to obtain estimates of experimental error from which to determine pen effects. The experiments were all nutrition experiments and were conducted at four experimental stations.Analyses were carried out on both a hen-housed and survivor basis. For all experiments the sampling error (individuals) underestimated the experimental error (individuals + pens) by about 20 per cent on a hen-housed basis. On a survivor basis there was no evidence of pen effects, that is, the sampling error did not underestimate the experimental error.The coefficient of variation for all experiments was 40 per cent on a hen-housed basis and 25 per cent on a survivor basis.The relative efficiency of two experimental designs, randomized block and completely randomized, was calculated for 11 of the experiments (on a hen-housed basis only). With the exception of 2 experiments, there was an increased efficiency of up to 500 per cent in utilizing a randomized block design. The data further indicate that the increase in efficiency obtained with a randomized block design is much more marked when the blocks represent different houses than when the blocks consist of different locations within a house.

Chicks from 10 broiler strains were randomly allotted and reared at three farms. At 10 weeks of age a random sample consisting of 60 birds of each strain, with an equal number of each sex, was taken at each farm, slaughtered and market graded. At each farm, an official inspector graded the birds according to the standards of the Canada Department of Agriculture. Each bird was graded for the four grade factors: conformation, fleshing, fat and dressing.The number of birds in each grade class was not independent of farm, sex or strain. The 10 strains, ranked on grade scores, tended to rank in the same order at each farm, although the agreement was better for some grade factors than others, and was better when based on males than on females. On a strain rank basis, the grade scores for any one grade factor were not, in general, indicative of the scores for any other grade factor. Also on a strain rank basis, there was a high positive correlation between breast angle and grade scores for fleshing: body weight was not correlated with grade scores for any of the four grade factors, with the possible exception of conformation in the case of males.

Three replicate trials were conducted to test the possibility that high mortality of non-specific origin being encountered in a genetic control strain of meat-type laying hens might be due to excessive energy intake. In each trial, the medium energy laying ration on which this strain of birds has been maintained for a number of years was compared with the same ration diluted with 20 per cent pulverized oat hulls, for a period in excess of 330 days.Mortality was not influenced by the energy content of the ration, nor was rate of egg production. The low energy ration reduced final body weight by only 0.1 to 0.2 pounds, suggesting that the birds on the control diet were not unduly fat. Comparison of these results with others reported in the literature leads to the speculation that mortality due to obesity may be a problem only in heavier and faster-growing strains than the strain used in this study.

Electrophoretic variants of serum esterases of domestic fowl have been shown to be inherited (Grunder, 1968) . This investigation also revealed that, regardless of electrophoretic phenotype, staining intensity of these esterases was significantly lighter for adult females than adult males. A preliminary unpublished investigation of 126 hens indicated that those with low staining intensity of esterase zones at about 124 days of age came into lay significantly sooner than those with zones of high staining intensity. Csuka and Petrovsky (1968) reported apparently the same esterase system and mentioned a negative association between enzyme staining intensity and earlyness of sexual maturity. Kimura (1969) reported electrophoretic variants of what appears to be the same esterase system. Other biochemical markers have been investigated in connection with production traits in poultry. Wilcox et al. (1963) obtained correlations which suggested that serum alkaline phosphatase level is genetically related to egg production as well as body weight, egg weight, albumen quality and shell strength.…

Data from the third and fourth generations of a number of lines selected exclusively for growth, and of a number selected solely for breast angle, showed that selection for these traits had an effect on the incidence of crooked keels and breast blisters in 63-day-old broilers. The base population of these selected lines was a meat-control strain and a sample of this strain was reared with each hatch of the selected lines.Lines selected for growth had the highest incidence of both crooked keels and breast blisters. The lines selected for breast angle had a lower incidence of these defects than the controls, even though they did not differ from the controls in 63-day weight. It was concluded that there is a definite relationship between rate of growth, breast development and the incidence of keel defects. Market grading data on a sample of birds from these lines reflected these differences in keel defects. The market grades for conformation were lowest in the growth lines and highest in the breast lines.

SUMMARY– The eating quality of meat from Pilgrim, Hungarian and Chinese geese and their crosses was examined in 88 geese, equal numbers of males and females, in two experimental plans. Flavor and tenderness were ranked by an experienced taste panel. A modified Warner-Bratzler shearing device was used for tenderness determinations. Data were obtained for cooking rates, yield, color and moisture content. Variance components were estimated for tenderness measurements on the Warner-Bratzler Shear. A difference among the genotypes was observed only for percent fat. Small, but statistically significant, differences between sexes were observed for cooking rate, percent meat, moisture of breast meat and color of breast and thigh meat.

IT HAS been shown by many investigators (see Landauer, 1951) that holding time and temperature have an effect on the hatchability of eggs. Funk et al. (1950) have reported that under optimum holding temperatures chicken eggs begin to decline in hatchability when held beyond 7 days. To the authors’ knowledge there have been no reports on the effect of length of holding on the hatchability of goose eggs. Since field reports indicate that many operators experience limited success in hatching goose eggs, it is of some importance to determine to what extent delayed setting depresses hatchability. This problem is also of interest to anyone carrying on a breeding program. It is desirable in breeding operations to keep the number of hatches that are required to supply replacement stock to a minimum, yet to accomplish this the breeder cannot afford too serious a loss in hatchability as a result of holding …

RELATIVELY few of the many reported estimates of genetic parameters for traits in the fowl have been based on control or unselected populations. In addition to characterizing the population itself, estimates based on such populations can be very useful in quantitative inheritance studies. King (1961) has pointed out that estimates on unselected populations based on the commonly used variance component analyses, are free of the bias that could result from selection of parents. Establishing changes, if any, in genetic parameters of selected lines drawn from the control population has been mentioned by King as being an important use for such estimates. The estimates reported in this study are based on a population of meat-type chickens maintained as a random bred control strain. The history and development of this strain have been previously reported by Merritt and Gowe (1962). Only traits, namely body weights and skeletal dimensions, obtained on both sexes …

SWANSON et al. (1964) have pointed out that informed management and breeding decisions with respect to meat-type poulty are dependent on reliable information on the various factors influencing market yeilds. A relatively recent example of an important investigation in this area is the study of Ash and Nothers (1964). These workers concluded that the degree of sexual dimorphism exhibited by market ducks for weight at market age and carcass fat was sufficient to justify different management practices and marketing ages for the two sexes. Unfortunately, there is a general lack of information on factors relating to market yield in the domestic goose. The present study was undertaken to obtain information on two of the more important factors, namely sex and genotype and any interaction between them, on market yield in this species. A broad spectrum of genotypes processed at a commercial plant provided data for this study so the findings…

CONSIDERABLE attention has been focused on problems of egg quality in the past. The possibility of improving egg quality traits by breeding methods has been investigated and it has been found that the three main “components” of egg quality, namely albumen quality, shell strength, and freedom from blood and meat spots, are influenced to different degrees by heredity. The present report deals with an investigation of the first two of these traits. In this study albumen height was the criterion of albumen quality and specific gravity was used as a measure of shell strength. The effectiveness of selection in improving albumen quality has been shown by several workers, (Lorenz and Taylor, 1940; Knox and Godfrey, 1940). Taylor and Lerner (1939) demonstrated the genetic basis for shell strength by establishing two lines, differing in shell strength, from one population. McClary and Lerner (1950) reported a heritability estimate of .15 for specific …

ACCURATE estimates of genetic parameters are essential for formulating applied breeding programs. An extensive number of estimates have been reported for some traits in the fowl; e.g. Siegel (1962) has summarized 178 reported estimates of heritability for juvenile body weight. On the other hand for certain economic traits of interest to breeders of meat type poultry, few estimates of heritability and fewer still of genetic correlations between them have been reported in the literature. Data on control strain populations maintained in a manner similar to that described by Gowe et al. (1959) are especially useful for obtaining genetic parameter estimates. First, such control strains are reproduced in a manner and from populations of a size that minimize inbreeding and second, the breeders are not selected on their own or related individuals phenotypic merit. King (1961) has pointed out that the selection of parents can lead to undetermined bias in the . . .

1. A total of 3236 females from eight meat-type strains, half of which were vaccinated for Marek's disease (MD), and 11,193 Leghorn females from ten strains, all vaccinated for MD, were adventitiously exposed to MD and lymphoid leukosis (LL) viruses and observed to 392 and 497 d of age, respectively. 2. In the meat-type birds, vaccination reduced total mortality from 43-4% to 27-1% and mortality due to MD from 16-4% to 5-4% but did not affect mortality and LL (2-9% and 3-4%). 3. In the vaccinated Leghorns total mortality was 11%, including 2-1% from MD and 1-2% from LL. 4. Significant differences between strains of chickens were found in total mortality, as well as in MD and LL mortality. 5. Strain by vaccination interaction was observed in total rearing and adult mortality, as well as in the MD mortality of adult meat-type females. 6. Leghorn strains with higher rate of egg production and meat-type strains with lower growth rate to have better viability.

Indirect systolic blood pressures were measured on females of three egg type strains of chickens over five consecutive generations. The measurements were taken between 165–175 days of age. Blood pressure measurements were also taken in one generation on breeder males at 380 days of age. Two of the strains were under selection for egg production traits while the third strain was a control derived from the same genetic base as one of the selected strains. Mean blood pressures were 148 mm. Hg for females and 203 mm. Hg for males. Heritability estimates for females averaged 0.26. Additive type of genetic expression of blood pressure was indicated. Mean blood pressure of birds dying (to 500 days of age) was significantly lower in the control and related selected strain than the mean blood pressure of survivors. In the other selected strain there was no relationship between blood pressure and mortality. A significant interaction was observed between strains and sexes. Genetic and phenotypic correlations with production and egg quality traits were for the most part of a low order of magnitude and relatively few of them statistically significant. The sign of the genetic correlation was positive for body weights and most egg quality traits but negative for egg production and age to first egg.

HATCHING egg size and its relationship to parent reproductive performance and progeny growth have been the subject of a number of investigations, because of the potential importance in the production of poultry meat (Goodwin, 1961; Merritt and Gowe, 1965). The high positive relationship between the size of the egg and the size of the hatched chick has been recognized, but it has generally been regarded that the relationship is no longer of practical significance by the time the bird reaches market age. Goodwin (1961) has shown, however, that on an intra-strain basis a 1 gram increase in egg weight can result in a 5 gram increase in market body weight (9 weeks). He found even larger inter-strain relationships in the same study. It has been well established from a number of intra-strain genetic studies that egg size and body size are positively correlated genetically, so that the relationship reported by…

THE close dependence of chick hatching weight on egg weight has been reported by many investigators (Upp, 1926; Galpin, 1938; Kosin et al., 1952). It has been generally conceded however, that the initial influence of egg size on chick size is short-lived and has no important effect on subsequent growth and could for all practical purposes be ignored. Goodwin (1961) however, has described the initial effect of egg weight on subsequent growth as being cumulative and has suggested that the influence of hatching egg size on market weight is of sufficient magnitude to be of practical importance in the broiler industry. To the extent that egg size effects on growth are environmental (e.g., due to age or season) the adequacy of random sample broiler tests and even experimental breeding and research investigations designed to reveal genetic differences in growth might also be questioned. Since further information on these egg size…

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The angle meter (Clark and Cunningham, 1949; Bywaters and Siegel, 1958) has been used for measuring breast “fleshing or development” in a number of breeding studies (Siegel, 1962). The simplicity of the angle meter, in contrast to other instruments and devices that have been employed for measuring breast development, and the speed with which measurements can be obtained, are probably among the chief reasons for its continued use. However, one disadvantage of the meter is that the “accuracy” of the readings is dependent to some extent upon the operator. (Bywaters and Siegel, 1958; and Merritt, unpublished data). Bywaters and Siegel, in recognizing this problem, suggested that for a given experiment the same operator should take all measurements. In selection experiments carried over a number of years and in other circumstances, it is not always possible to follow such a practice. Furthermore, the general use in research investigations of an instrument …

A NUMBER of studies (Randles, 1947; Rodewyk, 1950; Merritt and Gowe, 1956) have shown that geese lay more eggs in their second and even later years than they do in their first or pullet year. There is also some evidence from these studies that eggs laid by pullet geese do not hatch as well as eggs laid by the same birds as yearlings. Due to the natural increase in reproductive performance with age, geese are usually kept beyond their first year. For selective breeding purposes, it is necessary to make some allowance for the effect of age in order to compare the performance of individuals of different ages, and to make use of all records available on these individuals. The most satisfactory estimates of age effects (or age-correction factors) are from populations in which all individuals are given the opportunity to have repeat records regardless of their previous performance. It …

The juvenile growth of chickens was shown by Becker (1960) to be adversely affected when the eggs from which they hatched were stored longer than two weeks prior to incubation. Merritt (1964) confirmed Becker’s findings and reported similar hatching egg storage effects on adult weight, egg weight and juvenile and adult viability. On the other hand Proudfoot (1968) reported no hatching egg storage effects on a number of performance traits. Proudfoot’s study was based on eggs from a S. C. White Leghorn strain as opposed to the cited studies which were on meattype strains. He suggested that strain differences could be one reason for the lack of agreement between his and other studies. This hypothesis may be tenable although Merritt (1964) found no evidence that storage effects were the result of a genotype-environment (storage length) interaction on an intra-strain basis. Because of the normal increase in the size of eggs…