Boettcher P J, Steverink D W, Beitz D C, Freeman A E, McDaniel B T
Department of Animal Science, Iowa State University, Ames 50011, USA.
J Dairy Sci. 1996 Apr;79(4):655-62. doi: 10.3168/jds.S0022-0302(96)76411-1.
Effects of maternal lineage on yield traits were examined by using animal models. Data were 6054 multiparous records of 2264 cows from six herds in North Carolina and the breeding herd of Iowa State University. Separate analyses were performed by using first lactation records from North Carolina, all records from North Carolina, and pooled records from North Carolina and Iowa. Traits were mature equivalent yields of milk, fat, and protein; percentages of fat and protein; and milk energy concentration and yield. Cattle were assigned to maternal lineages on the basis of the earliest female ancestor recorded. Fixed effects in the models were herd-year-season, parity, and maternal lineage; random effects were animal, permanent environment, and residual. All additive genetic relationships were considered. For all analyses, maternal lineage was associated with significant differences in fat percentage and milk energy concentration. Differences between maternal lineages for yield traits were not significant. Variance components were also obtained with REML using the same data and models, but with lineage as a random effect. Based on records pooled from Iowa and North Carolina, maternal lineage accounted for 2.7% of the variance in fat percentage. Otherwise, < 1.2% of the variance of any trait was associated with maternal lineage.
通过使用动物模型研究了母系血统对产量性状的影响。数据来自北卡罗来纳州六个牛群和爱荷华州立大学育种牛群的2264头母牛的6054条经产记录。分别使用北卡罗来纳州的头胎泌乳记录、北卡罗来纳州的所有记录以及北卡罗来纳州和爱荷华州的汇总记录进行分析。性状包括乳、脂肪和蛋白质的成熟当量产量；脂肪和蛋白质的百分比；以及乳能量浓度和产量。根据记录到的最早母系祖先将牛分配到母系血统中。模型中的固定效应是牛群-年份-季节、胎次和母系血统；随机效应是个体、永久环境和残差。考虑了所有加性遗传关系。对于所有分析，母系血统与脂肪百分比和乳能量浓度的显著差异相关。母系血统之间产量性状的差异不显著。还使用相同的数据和模型通过REML获得方差成分，但将血统作为随机效应。基于爱荷华州和北卡罗来纳州汇总的记录，母系血统占脂肪百分比方差的2.7%。否则，任何性状方差的<1.2%与母系血统相关。
