Non-genetic and genetic effects related to birth and weaning weights of crossbred dairy goats

The objectives of this study were to assess the effect of some non-genetic factors, breed and heterosis on birth weight and weaning weight in crossbred dairy kids, and to estimate genetic parameters of these traits in a multi-breed dairy goat farm. Non-genetic analysis revealed that sex, year and season of birth and litter size are important factors that affect birth and weaning weights. Estimates of heritabilities for direct genetic effects were moderate at birth and weaning (0.25 ± 0.06 and 0.24 ± 0.10, respectively). Heritability of maternal genetic effect for birth weight was 0.26 ± 0.03. The bivariate analysis also revealed that permanent maternal effects are significant for birth and weaning weights indicating that this component should be considered in management strategies. These results highlight the importance of considering non-genetic factors to design management strategies in combination with genetic selection strategies to improve the future performance of replacement of does.