上海荷斯坦奶牛头胎与二胎日产奶量性状遗传力和遗传相关对比分析

当前,上海正组建我国南方地区荷斯坦奶牛基因组选择参考群体,而研究并对比分析上海荷斯坦奶牛头胎与二胎产奶量的遗传力和遗传相关是全基因组关联分析和基因组选择的基础。本研究收集并整理上海光明乳业旗下奶牛场2007~2013年6年间荷斯坦奶牛的43余万条奶牛群体改良(DHI)测定日记录,并采用随机回归模型对头胎和二胎的产奶量的遗传力和遗传相关进行估计。结果显示日产奶量性状头胎奶牛遗传力在0.125与0.475之间变化,二胎遗传力在0.155与0.34之间变化,变化趋势都是在泌乳期内先增大后减小,且头胎奶牛遗传力峰值大于二胎奶牛。头胎和二胎测定日产奶量间均有较高的遗传相关,但二胎整体的遗传相关程度较头胎测定日间小。该研究结果为上海地区荷斯坦奶牛基因组选择参考群体的构建和制定合理的选育计划,奠定了必要的理论依据。

Comparison of Heritability and Genetic Correlation for Milk Yields of First and Second-Lactation Shanghai Holstein Cows

Currently,the reference population of Chinese Holsteins cows is being built for genomic selection in Shanghai,and estimating and comparing the heritability and genetic correlation for milk yield of first and second lactation is the basis of genomic selection.A total of 430 thousand DHI test-day milk yield records of Chinese Holstein cows which calved between 2007 and 2013 were used in this study.Random regressions were fitted for additive genetic and permanent environmental effects.The results showed that the heritability ranged from 0.125 to 0.475 for milk yields of primiparous cows,and ranged from 0.155 to 0.34 for second-parity cows.The change trends in lactation period are increased firstly and then decreased,and the peak value of heritability of first-parity is greater than the second-parity.The high genetic correlation between daily milk yields was also detected for both first-parity and second-parity.The study results lay a necessary theoretical basis for reference population construction for genome selection and make reasonable breeding plan of Holstein cow in Shanghai.