Heritability of Egg Production of Chickens: A Meta-analysis

【Objective】Egg production is a major selected trait in the breeding of layer and broiler breeder. A number of researches and reports on the heritability of egg production have been conducted, however, the results were discrepant, which resulted in the tough choice of breeders. The meta-analysis aimed to evaluate the heritability of egg production of layers, broiler breeders and local chickens and the dynamics on the heritability.【Method】Relevant documents on the evaluation of heritability of egg production published at home and abroad from 1990 to 2019 were collected by searching the databases of CNKI, ISI web of science, PubMed, EBSCO and ProQuest. A total of 72 papers were included in the meta analysis. The dataset of the heritability of egg production was assessed with random effect model, subgroup analysis and two stepwise regression analysis.【Result】Random effect model showed that the heritability of egg production was 0.234±0.009 and there were great differences between different studies. Subgroup analysis showed that the heritability of white shelled layers and brown shelled layers was 0.242±0.022 and 0.224±0.017, respectively, and that of broiler breeders and local chickens was 0.221±0.029 and 0.240±0.014, respectively. The heritability showed a declining trend during late laying period. Regression analysis showed that the heritability function expressed as: h2=-0.0023t+0.2253.【Conclusion】A small proportion of egg production variation could attribute to the genetic factors, and the genetic background and week age might contribute to the heterogeneity between different studies.