Leite C D S, Lui J F, Albuquerque L G, Alves D N M
Departamento de Zootecnia, Universidade Federal de Viçosa, Viçosa, MG, Brasil.
Genet Mol Res. 2011 Nov 4;10(4):2692-701. doi: 10.4238/2011.November.4.2.
We examined the effects of environmental and genetic factors on the weaning-to-estrus interval (WEI) in sows. In order to perform the analyses of the environmental factors, 8104 observations of the 1st to the 6th WEI were carried out, while 6548 observations of the 1st to the 3rd WEI were carried out for the analyses of genetic factors. The environmental model included as fixed effects, herd, genetic line, year and season of birth, as well as the covariates, age of sow at farrowing, litter size at birth and lactation length. Genetic analysis was performed by repeatability and multitrait models. The mean and coefficient of variation for WEI were 7.02 days and 100.6%, respectively. The linear effect of lactation length and the quadratic effect of the age of sow at farrowing affected the WEI. Herd, year and season of farrowing were significant sources of variation for WEI, and there was no influence of genetic line or of litter size at birth. Heritability estimated by the repeatability model was 0.04, while heritabilities obtained by the multitrait model were 0.07, 0.02 and 0.07 for the first three WEI, respectively. Estimates of genetic correlations among the different WEI were of moderate to low magnitude. It was concluded that environmental factors, such as year and season of farrowing, lactation length, age of sow at farrowing and herd, should be considered in the model for best estimation of genetic parameters for this trait. Although with only a small possible genetic gain, selection can be made based on the first WEI.
我们研究了环境和遗传因素对母猪断奶至发情间隔（WEI）的影响。为了分析环境因素，对第1至第6次WEI进行了8104次观测，而对第1至第3次WEI进行了6548次观测以分析遗传因素。环境模型包括固定效应，如猪群、遗传品系、出生年份和季节，以及协变量，产仔时母猪年龄、出生时窝仔数和哺乳期长度。通过重复性和多性状模型进行遗传分析。WEI的均值和变异系数分别为7.02天和100.6%。哺乳期长度的线性效应和产仔时母猪年龄的二次效应影响了WEI。产仔的猪群、年份和季节是WEI变异的重要来源，遗传品系或出生时窝仔数没有影响。重复性模型估计的遗传力为0.04，而多性状模型对前三次WEI获得的遗传力分别为0.07、0.02和0.07。不同WEI之间的遗传相关性估计值为中等至低水平。得出的结论是，在该性状遗传参数的最佳估计模型中应考虑环境因素，如产仔年份和季节、哺乳期长度、产仔时母猪年龄和猪群。尽管遗传增益可能很小，但可以基于第一次WEI进行选择。
