Influence of sex chromosomes on laying-house performance of chickens |
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| Authors: | D M Briggs A W Nordskog |
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| Affiliation: | 1. Department of Animal Science , Iowa State University of Science and Technology , Ames, Iowa, 50010, USA;2. Department of Poultry Science , North Carolina State University , Raleigh, North Carolina, 27607, USA;3. Department of Animal Science , Iowa State University of Science and Technology , Ames, Iowa, 50010, USA |
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| Abstract: | A special population segregating for the sex chromosome was developed to estimate the Z and W sex chromosome effects sampled from a Fayoumi (Egyptian) breed and a heavy‐breed synthetic population. Analysis of 2 years’ data from more than 3000 pullets indicate that both sex chromosomes influence age at first egg with the Z being the more important. Pullets with the heavy‐breed Z chromosome matured 17 d earlier and laid 5% more eggs than those with the Fayoumi Z. The heavy‐breed W chromosome showed a 7‐d advance in maturity but otherwise with no significant effect on egg production. Although this experiment was designed to estimate parameter differences between two breeds, the design can be generalised to estimate the distribution of genetic differences due to autosomes, sex chromosomes, heterosis and maternal influences both between and within avian populations. |
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