奶牛体型线性性状的动物模型遗传评估

本文利用北京市7个奶牛场的奶牛体型线性评定资料,累计收集了4年共1647头母牛的15个线性性状数据,采用最佳线性无偏预测(BLUP,Best Linear Unbiased Prediction)方法,配合个体动物模型(AM,Animal Model),估计了胎次、泌乳月、鉴定日期、奶牛场以及鉴定员等固定环境效应,并计算出了每头奶牛15个线性性状的个体育种值。鉴于奶牛体型线性评定方法在国内正处于推广应用阶段,而BLUP的动物模型方法目前在国内的研究应用也少见报道。本文通过将两者结合起来,估计动物个体的种用价值,结果表明奶牛体型线性评定以第三胎、第三个泌乳月效果较好。经济效益好的场队其牛群也较整齐。不同的鉴定日期、不同的鉴定员对评定结果也略有影响。最后,可以得到剔除固定效应并经过排序用于选择的奶牛个体育种值。处理分析表明效果比较理想,为推动我国的动物育种工作,建议今后在国内大力推广奶牛体型线性评定和动物模型BLUP评估相结合的育种方法和手段。

GENETIC EVALUATION OF LINEAR TYPE TRAITS WITH ANIMAL MODEL (AM)

Linear classification data on 15 traits were analysed by BLUP method with AM. The data collected from 1647 cows which located in 7 herds in Beijing area were made by 4 classifiers within 4 years, from 1987~1990. Individual breeding value of 15 traits on each animal were computed with consideration of fixed environmental effects including parity, lactating month, classification date, herd and classifier. Since linear classification program was being on a stage of extention and research of AM-BLUP was reported rarely in the publications, this research tried to combine the two methods to evaluate the breeding value of individual animal. Results indicated that suitable time for conducting linear classification was in the third lactating month of third parity and different classification date and classifier had slight influence on evaluation results. In the better herds having better economic benefit, the cow population was better. Finally, the individual value excluding fixed effects could be obtained for rating animals to be selected. Computing results showed a better ideal effect. This advanced breeding method of combining linear classification with AM-BLUP should be applicated and disseminated greatly to improve animal breeding work in our country.