Hansen M, Lund M S, Sørensen M K, Christensen L G
Department of Animal Breeding and Genetics, Danish Institute of Agricultural Sciences, Research Centre Foulum, Tjele.
J Dairy Sci. 2002 Feb;85(2):445-52. doi: 10.3168/jds.S0022-0302(02)74093-9.
The primary aim of this study was to estimate genetic correlations between dairy character, protein yield, clinical mastitis, and other diseases. Data consisted of first lactation records of Danish Holstein cows calving from 1990 to 1999. After editing, the data included records on 934,639 cows, of which 101,853 were assessed for dairy character, 472,421 for diseases, and 834,993 for protein yield. The disease traits were defined as binary traits in the period from 10 d before to 50 d after calving for clinical mastitis, and from 10 d before to 100 d after calving for diseases other than mastitis. Data were analyzed with a linear sire model using the method of AI-REML. Heritabilities were estimated to be 0.265 for protein yield, 0.261 for dairy character, 0.035 for clinical mastitis, and 0.020 for diseases other than mastitis. Estimates of genetic correlations between protein yield and dairy character, protein yield and clinical mastitis, and protein yield and diseases other than mastitis were 0.38, 0.33, and 0.14. Between the two disease traits, the genetic correlation was 0.24. The genetic correlation between dairy character and clinical mastitis was 0.24. Between dairy character and diseases other than mastitis the genetic correlation was 0.41. Thus, cows with high score for dairy character were more prone to diseases. The genetic correlation between dairy character and the disease traits, when both traits were adjusted for protein yield, was 0.13 for clinical mastitis and 0.39 for diseases other than mastitis. These findings suggest that, dairy character should be given a negative rather than a positive weight in the breeding goal.
本研究的主要目的是估计产奶性状、蛋白质产量、临床型乳房炎及其他疾病之间的遗传相关性。数据包括1990年至1999年产犊的丹麦荷斯坦奶牛的头胎泌乳记录。经过编辑后，数据包含934,639头奶牛的记录，其中101,853头奶牛评估了产奶性状，472,421头奶牛评估了疾病情况，834,993头奶牛评估了蛋白质产量。疾病性状被定义为二元性状，临床型乳房炎为产犊前10天至产犊后50天，除乳房炎外的其他疾病为产犊前10天至产犊后100天。使用AI-REML方法，通过线性父系模型对数据进行分析。蛋白质产量的遗传力估计为0.265，产奶性状为0.261，临床型乳房炎为0.035，除乳房炎外的其他疾病为0.020。蛋白质产量与产奶性状、蛋白质产量与临床型乳房炎、蛋白质产量与除乳房炎外的其他疾病之间的遗传相关性估计分别为0.38、0.33和0.14。两种疾病性状之间的遗传相关性为0.24。产奶性状与临床型乳房炎之间的遗传相关性为0.24。产奶性状与除乳房炎外的其他疾病之间的遗传相关性为0.41。因此，产奶性状得分高的奶牛更容易患病。当对产奶性状和疾病性状都校正蛋白质产量后，产奶性状与临床型乳房炎之间的遗传相关性为0.13，与除乳房炎外的其他疾病之间的遗传相关性为0.39。这些发现表明，在育种目标中，产奶性状应给予负权重而非正权重。
