Rogers G W, Hargrove G L, Cooper J B
Department of Dairy and Animal Science, Pennsylvania State University, University Park 16802, USA.
J Dairy Sci. 1995 Apr;78(4):914-20. doi: 10.3168/jds.S0022-0302(95)76706-6.
Genetic and phenotypic correlations were estimated for means of log2 SCC (somatic cell scores) from the first 305 d, the first 75 d, the first 150 d, 76 to 305 d, and 151 to 305 d of lactation for first and second lactations using REML. Somatic cell scores from the Dairy Records Processing Center in Raleigh, North Carolina for 31,180 Jersey cows sired by 411 bulls were used for analyses. Correlations between sire evaluations for somatic cell scores from this study and linear type traits from the American Jersey Cattle Club were also calculated. The model used for analyses of the somatic cell score means included herd-year of calving, age at first calving, sire, and residual. Heritability estimates for the means ranged from .05 to .15 (.12 for 305-d mean for first lactation). Genetic correlations among the somatic cell score means within first and within second lactation were > or = .79. The genetic correlation between the 305-d mean from first and second lactation was .90. The smallest genetic correlation across lactations was .68. Somatic cell scores measured at various times were under similar genetic control. Phenotypic correlations were usually much smaller than genetic correlations.(ABSTRACT TRUNCATED AT 250 WORDS)
利用限制最大似然法（REML），对首次泌乳和第二次泌乳的前305天、前75天、前150天、76至305天以及151至305天的log2体细胞评分（SCC）均值进行了遗传和表型相关性估计。分析使用了北卡罗来纳州罗利市奶牛记录处理中心的31180头泽西奶牛的体细胞评分，这些奶牛由411头公牛所生。还计算了本研究中体细胞评分的父系评估与美国泽西牛俱乐部线性类型性状之间的相关性。用于分析体细胞评分均值的模型包括产犊年份、首次产犊年龄、父系和残差。均值的遗传力估计范围为0.05至0.15（首次泌乳305天均值为0.12）。首次泌乳和第二次泌乳内体细胞评分均值之间的遗传相关性≥0.79。首次泌乳和第二次泌乳305天均值之间的遗传相关性为0.90。不同泌乳期之间最小的遗传相关性为0.68。不同时间测量的体细胞评分受相似的遗传控制。表型相关性通常远小于遗传相关性。（摘要截短至250字）
