Schalles R R, Cundiff L V
Department of Animal Sciences and Industry, Kansas State University, Manhattan 66506, USA.
J Anim Sci. 1999 May;77(5):1144-7. doi: 10.2527/1999.7751144x.
A form of congenital hypotrichosis, commonly know as the "rat-tail syndrome," occurs in a small percentage of calves produced by crossing some Continental cattle breeds with cattle that are black in color. These calves are characterized by short, curly, malformed, sometimes sparse hair and a lack of normal tail switch development. In our first study, performance of 43 rat-tail calves was compared with that of 570 non-rat-tail calves of the same breeding and contemporary groups. All rat-tail calves were sired by Simmental bulls and were from cows with various percentages of Angus breeding. The rat-tail condition had no effect on birth weight, weaning weight, or gain from birth to weaning. However, rat-tail calves had significantly lower rates of gain during the winter months from weaning to yearling than non-rat-tail calves, resulting in a 19 kg lighter yearling weight. Gains of steers from yearling to slaughter were not significantly different, but rat-tail steers were 36 kg lighter (P = .01) and 13 d older (P = .15) at slaughter than the non-rat-tail steers. In a second study, Angus-Simmental F1 males and females with the rat-tail condition were mated to produce 64 F2 offspring that were used to determine the mode of inheritance of this syndrome. Analysis showed that the rat-tail syndrome is controlled by interacting genes at two loci. Cattle that express the syndrome must have at least one dominant gene for black color and be heterozygous at the other locus involved.
一种先天性少毛症，通常被称为“鼠尾综合征”，在一些欧洲大陆牛品种与黑色牛杂交所产的一小部分犊牛中出现。这些犊牛的特征是毛发短、卷曲、畸形，有时稀少，且缺乏正常的尾梢发育。在我们的第一项研究中，将43头患鼠尾综合征的犊牛与来自相同育种和同期群体的570头非鼠尾犊牛的性能进行了比较。所有患鼠尾综合征的犊牛均由西门塔尔公牛所生，其母牛具有不同比例的安格斯血统。鼠尾综合征对出生体重、断奶体重或从出生到断奶的生长速度没有影响。然而，患鼠尾综合征的犊牛在冬季从断奶到周岁期间的生长速度明显低于非鼠尾犊牛，导致周岁体重轻19千克。阉牛从周岁到屠宰时的生长速度没有显著差异，但患鼠尾综合征的阉牛在屠宰时比非鼠尾阉牛轻36千克（P = 0.01），且屠宰时年龄大13天（P = 0.15）。在第二项研究中，将患有鼠尾综合征的安格斯 - 西门塔尔F1代公母牛进行交配，产生了64头F2代后代，用于确定该综合征的遗传模式。分析表明，鼠尾综合征由两个基因座上的相互作用基因控制。表现出该综合征的牛必须至少有一个黑色的显性基因，并且在另一个相关基因座上是杂合的。
