Schutz M M, Freeman A E, Beitz D C, Mayfield J E
Department of Animal Science, Iowa State University, Ames 50011.
J Dairy Sci. 1992 May;75(5):1331-41. doi: 10.3168/jds.S0022-0302(92)77884-9.
Maternal lineage effects on milk yield traits, considered indicative of cytoplasmic inheritance, were evaluated with animal models. Cattle were from a selection experiment begun in 1968. Maternal pedigrees were traced to the first female member in the Holstein-Friesian Herdbook; purchased cows entering the herd, considered foundation females, were assigned to maternal lineage groups. All models accounted for year-season of calving, parity, and selection lines. Maternal lineage effects were included in a repeated records model with cow effects and preadjustment for sire and maternal grandsire transmitting abilities. Maternal lineage accounted for 5.2, 4.1, and 10.5% of phenotypic variation of preadjusted records of milk yield, fat yield, and fat percentage, respectively. Maternal lineage was evaluated as a fixed effect in an animal model including random animal and permanent environmental effects. Maternal lineage significantly affected fat percentage but not milk yield. Maternal genetic (nuclear) effects and their covariance with additive animal effects did not significantly account for additional variation nor did they influence maternal lineage estimates. Maternal lineage affected calculated net energy of milk but was not important for SNF yield or concentration. Maternal lineage influenced fat percentage, energy concentration, and, to a lesser extent, fat yield in milk of dairy cattle.
利用动物模型评估了母系血统对产奶性状的影响，这些影响被认为是细胞质遗传的指标。牛群来自于1968年开始的一项选择试验。母系谱系追溯到荷斯坦-弗里生牛品种登记簿中的第一位雌性成员；进入牛群的外购母牛，即基础母牛，被分配到母系血统组。所有模型都考虑了产犊的年份季节、胎次和选择品系。母系血统效应被纳入一个重复记录模型，该模型包含母牛效应，并对父系和母系祖父的传递能力进行了预调整。母系血统分别占预调整后产奶量、产脂量和乳脂率记录的表型变异的5.2%、4.1%和10.5%。在一个包含随机动物效应和永久环境效应的动物模型中，将母系血统作为固定效应进行评估。母系血统显著影响乳脂率，但不影响产奶量。母系遗传（核）效应及其与加性动物效应的协方差并未显著解释额外的变异，也未影响母系血统估计值。母系血统影响计算出的牛奶净能量，但对非脂固形物产量或浓度并不重要。母系血统影响乳脂率、能量浓度，并在较小程度上影响奶牛牛奶中的产脂量。
