The model used was the sire model containing herd-year-season(HYS)effect(fixed),sire group effect(fixed) and sire effect(random), which is widely used in dairy cattle breeding.

• 方差组分估计所用的模型为奶牛育种中常用的公畜模型,它包括场年季固定效应、公牛组固定效应和公牛随机效应。