Department of Farm Animal Health, Utrecht University, PO Box 80.151, 3508 TD Utrecht, The Netherlands.
Anim Reprod Sci. 2013 Feb;137(1-2):1-7. doi: 10.1016/j.anireprosci.2012.12.006. Epub 2012 Dec 20.
Failure of the timely expulsion of the fetal membranes, called retained placenta, leads to reduced fertility, increased veterinary costs and reduced milk yields. The objectives of this study were to concurrently look at the heritable and non-heritable genetic effects on retained placenta and test the hypothesis that a greater coefficient of relationship between dam and calf increases the risk of retained placenta in the dam. The average incidence of retained placenta in 43,661 calvings of Meuse-Rhine-Yssel cattle was 4.5%, ranging from 0% to 29.6% among half-sib groups. The average pedigree based relationship between the sire and the maternal grandsire was 0.05 and ranged from 0 to 1.04. Using a sire-maternal grandsire model the heritability was estimated at 0.22 (SEM=0.07) which is comparable with estimates for other dual purpose breeds. The coefficient of relationship between the sire and the maternal grandsire had an effect on retained placenta. The coefficient of relationship between the sire and the maternal grandsire was used as a proxy for the coefficient of relationship between dam and calf, which is correlated with the probability of major histocompatibility complex (MHC) class I compatibility between dam and calf. MHC class I compatibility is an important risk factor for retained placenta. Although the MHC class I haplotype is genetically determined, MHC class I compatibility is not heritable. This study shows that selection against retained placenta is possible and indicates that preventing the mating of related parents may play a role in the prevention of retained placenta.
胎衣未能及时排出，称为胎衣不下，会导致繁殖力下降、兽医成本增加和产奶量减少。本研究的目的是同时研究胎衣不下的遗传和非遗传因素，并检验这样一个假设，即母畜和犊牛之间的亲缘关系系数越大，母畜发生胎衣不下的风险就越高。在梅斯-莱茵-伊塞尔牛的 43661 次分娩中，胎衣不下的平均发病率为 4.5%，半同胞组的发病率从 0%到 29.6%不等。基于系谱的父本与母本外祖父之间的平均亲缘关系系数为 0.05，范围从 0 到 1.04。使用父本-母本外祖父模型，估计的遗传力为 0.22（SEM=0.07），与其他两用品种的估计值相当。父本与母本外祖父之间的亲缘关系系数对胎衣不下有影响。父本与母本外祖父之间的亲缘关系系数被用作母畜与犊牛之间的亲缘关系系数的替代指标，而后者与母畜与犊牛之间主要组织相容性复合体（MHC）I 类的兼容性概率相关。MHC I 类兼容性是胎衣不下的一个重要危险因素。虽然 MHC I 类单倍型是由遗传决定的，但 MHC I 类的兼容性是不可遗传的。本研究表明，对胎衣不下的选择是可能的，并表明防止近亲交配可能在预防胎衣不下方面发挥作用。
