Department of Genetics and Biotechnology, Faculty of Agricultural Science, University of Aarhus, Tjele, Denmark.
J Anim Breed Genet. 2010 Dec;127(6):442-51. doi: 10.1111/j.1439-0388.2010.00872.x. Epub 2010 Oct 28.
The aims of this study are to estimate variance components of litter size and kit survival rate and estimate genetic correlations of litter size and kit survival rate with dam's juvenile body weight and pregnancy length. Variance components for litter size and kit survival were analysed using an AI-REML approach, based on data from 1940 litters of the black colour type mink from 1996 to 2001. The models included (i) additive genetic effect of dam; (ii) dam and sire genetic effects; (iii) additive genetic effect of dam in relation to litter size and dam and sire genetic effects in relation to survival rate; (iv) additive genetic effect of dam to estimate the correlations of litter size or kit survival with dam juvenile body weight and pregnancy length on yearling dams (1357 litters). The dam heritabilities were of litter size (0.02-0.08) and survival rate (0.05-0.10). The permanent effects of dam were important for litter size (0.15-0.19) but not for survival rate. A positive dam genetic correlation between litter size and survival rate was found at 1 week postpartum (0.42), and a positive sire genetic correlation between number of weaned kits and survival rate at the age of 6 month (0.72). Litter size and survival rate were genetically antagonistically related to dam's juvenile body weight (-0.34 to -0.53). These results indicate the following: (i) it is possible to improve litter size and kit survival by selection, (ii) effective improvement of kit survival rate in the suckling period requires selection for maternal effect on kit survival and kit's own capacity to survive and later in the growth period for kit's own ability to survive and (iii) antagonistic genetic correlation of dam juvenile body weight with litter size and survival rate should be taken into consideration in mink breeding programs.
本研究的目的是估计产仔数和幼仔成活率的方差分量，并估计产仔数和幼仔成活率与母兽幼体体重和妊娠长度的遗传相关性。基于 1996 年至 2001 年的 1940 窝黑色水貂的数据，采用 AI-REML 方法分析了产仔数和幼仔成活率的方差分量。模型包括：（i）母兽的加性遗传效应；（ii）母兽和父兽的遗传效应；（iii）母兽与产仔数的加性遗传效应以及母兽和父兽与成活率的遗传效应；（iv）母兽的加性遗传效应，以估计产仔数或幼仔成活率与 1 龄母兽的幼体体重和妊娠长度的相关性（1357 窝）。产仔数的母兽遗传力为 0.02-0.08，成活率为 0.05-0.10。母兽的永久性效应对产仔数很重要（0.15-0.19），但对成活率没有影响。产后 1 周时发现产仔数和成活率之间存在正的母兽遗传相关（0.42），6 月龄时断奶幼仔数和成活率之间存在正的父兽遗传相关（0.72）。产仔数和成活率与母兽幼体体重呈遗传拮抗关系（-0.34 至-0.53）。这些结果表明：（i）通过选择可以提高产仔数和幼仔成活率；（ii）有效提高哺乳期幼仔成活率需要选择母兽对幼仔成活率的影响以及幼仔自身的生存能力，后期在生长阶段需要选择幼仔自身的生存能力；（iii）在水貂育种计划中应考虑母兽幼体体重与产仔数和成活率的遗传拮抗关系。
