Heringstad B, Sehested E, Steine T
Department of Animal and Aquacultural Sciences, Norwegian University of Life Sciences, PO Box 5003, N-1432 As, Norway.
J Dairy Sci. 2008 Nov;91(11):4437-9. doi: 10.3168/jds.2008-1330.
Correlated selection responses in lactation mean somatic cell score (LSCS) were estimated for groups of cows selected for high protein yield and low mastitis frequency, respectively. Selection for increased milk production resulted in an unfavorable correlated response for LSCS, whereas direct selection against clinical mastitis resulted in a favorable correlated selection response. After 6 cow generations, the genetic difference between the high protein yield group and the low mastitis group was 0.3 units LSCS, equivalent to a difference in somatic cell count of approximately 15,000, assuming deviations from a population mean LSCS of 4.1.
分别对选择高蛋白产量和低乳腺炎发病率的奶牛群体估计了泌乳期平均体细胞评分（LSCS）的相关选择反应。选择提高产奶量会导致LSCS出现不利的相关反应，而直接选择对抗临床乳腺炎则会产生有利的相关选择反应。经过6代奶牛选育后，高蛋白产量组和低乳腺炎组之间的遗传差异为0.3个LSCS单位，假设偏离群体平均LSCS为4.1，则相当于体细胞计数相差约15,000。
