Effects of Deviations from Normality on Selection Intensities for Shell Deformation and Egg Weight in Chickens

Brah, G.S.; Lanza, Gregory M.; Potts, P. L.; Washburn, K. W.

doi:10.3382/ps.0610424

Cited by 4 publications

(2 citation statements)

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“…Both genetic and environmental factors may contribute to non-normality of distributions showing that even in a non-commercial population, like the Vasca breed, the assumption of normality would be misleading, the intensity of selection could not be determined from tables of the normal distribution and so the response to selection could not be predicted. Brah et al (1982) reported significant and positive skewness and kurtosis for shell strength, measured by non-destructive deformation, and egg weight.…”

Section: Discussionmentioning

confidence: 96%

Relationship between egg‐shell colour and two measurements of shell strength in the Vasca breed

Campo

Escudero

1984

British Poultry Science

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1. Egg-shell colour, egg specific gravity, shell thickness and egg weight were determined for 2080 eggs from three varieties of the Vasca, a Spanish brown-egg-laying hen. 2. Intermediate, positive and significant (P < 0·01) correlation coefficients were found between egg-shell colour and specific gravity (0·25), or shell thickness (0·21). There was a very high (0·84), significant (P < 0·01) correlation between the measures of shell strength. 3. Shell thickness was accurately predicted with both specific gravity and egg weight as independent variables (determination coefficient 0·74); eggshell colour did not explain any further variation. 4. All traits showed considerable departure from normality in the form of negative kurtosis (shell colour and specific gravity), positive kurtosis (shell thickness and egg weight), negative skewness (shell thickness) or positive skewness (egg weight). 5. Egg-shell colour, specific gravity and shell thickness were less in July, in old birds and in eggs laid in the morning. Differences in egg quality traits between the three varieties were not significant.

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Section: Discussionmentioning

confidence: 96%

Relationship between egg‐shell colour and two measurements of shell strength in the Vasca breed

Campo

Escudero

1984

British Poultry Science

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“…Recent studies with layer chickens (CLAYTON 1975;BRAH and DEV 1979;BRAH et al 1982;CHAUDHARY et al 1984) have shown that this assumption may not hold true for several economic characters. In particular, age at sexual maturity, egg production, fertility, hatchability and egg-shell deformation exhibited considerable departures from normality of distribution.…”

Section: Introductionmentioning

confidence: 99%

Normality of distribution of juvenile body weights in meat‐type chickens

Brah¹,

Dev²

1987

J Animal Breeding Genetics

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Poultry genetics, breeding and biotechnology

Muir¹,

Aggrey²

2003

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This book contains articles on the quantitative and molecular genetics of poultry, the uses of transgenic technology, and genetics of disease resistance and transmission. It is divided into 4 parts: problems and issues associated with poultry breeding (part 1; 6 chapters); breeding strategies and objectives (part 2; 9 chapters); disease resistance and transmission (part 3; 7 chapters); and the use of genomics and bioinformatics in poultry (part 4; 12 chapters).

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Effects of Deviations from Normality on Selection Intensities for Shell Deformation and Egg Weight in Chickens

Cited by 4 publications

References 2 publications

Relationship between egg‐shell colour and two measurements of shell strength in the Vasca breed

Relationship between egg‐shell colour and two measurements of shell strength in the Vasca breed

Normality of distribution of juvenile body weights in meat‐type chickens

Poultry genetics, breeding and biotechnology

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