上海荷斯坦牛初产日龄的遗传力估计
Genetic estimation of age at first calving in Shanghai Holsteins

上海荷斯坦奶牛产奶性能经持续的选择得到显著的遗传改良,目前母牛主要面临使用寿命短这一关键问题。研究发现,造成使用寿命短的主要因素是繁殖障碍等,初产日龄是奶牛繁殖性状的一个重要指标,在遗传评估模型中考虑这一指标将有望延长母牛使用寿命,进而提高生产效益。性状遗传参数的估计是进行性能遗传评估的基础,本研究通过对上海地区2006－2017年间的24 201头上海荷斯坦牛初产日龄记录进行遗传参数估计,揭示当前上海荷斯坦牛群体性状特征。结果表明,上海荷斯坦牛平均初产日龄为(763.21±57.64) d,遗传力为0.23。本研究为上海荷斯坦牛初产日龄的育种工作提供了可靠的参数,且研究发现该性状的遗传力较低,表明其更适于使用基因组选择。
The performance of milk production in Shanghai Holsteins has improved significantly due to continuous selection.At present,the critical problem mainly faced by this breed is their short service life.A lot of studies have revealed that the major cause of short functional longevity is reproductive disorders.The age at first calving is an important indicator of reproductive traits of dairy cattle and the inclusion of the index of age at first calving in their genetic assessment model is expected to extend their functional longevity and also improve their production efficiency.The estimation of genetic parameters of traits is the basis for performance genetic assessment.In our research,the genetic parameters were estimated from 24 201 Shanghai Holsteins within a period of 11 years (2006 to 2017),revealing the characteristics of the population of Shanghai Holstein cattle.The results showed that the mean age at first calving was 763.21±57.64 days and the heritability was 0.23.The research provided reliable parameters for the breeding program of age at first calving in Shanghai Holsteins.Due to the low heritability obtained from the study,this indicates that the trait is more suitable for genome selection.