<p>Data from 1,512 Californian and 1,370 New Zealand White rabbits were analyzed by least squares procedures to study the effect of inbreeding of individuals, a covariate in the mathematical model, on body weights from weaning to slaughter and dressing percentage. Both linear and quadratic regression coefficients of inbreeding of rabbits were important for weights at several ages. Inbreeding of rabbits did not affect their performances at weaning and 5 weeks of age, but had an important effect on body weights measured from 6 to 11 weeks of age, with increases of performance from F=0 up to F=10% and reductions after that level. The effect of inbreeding was small on the weights observed at slaughter, and the trend was of reduction of weights when F increased. The same trend was observed for dressing percentage.</p> | <p>Os pesos individuais semanais da desmama ao abate de 2.882 coelhos, sendo 1.512 da raça Califórnia e 1.370 da raça Nova Zelândia Branca foram analisados pelo método dos quadrados mínimos para verificação dos efeitos da endogamia, uma covariável no modelo matemático, no desempenho desses animais. Tanto os efeitos lineares quanto quadráticos da endogamia dos coelhos foram importantes para pesos individuais a diversas idades. A endogamia dos coelhos não afetou seu desempenho à desmama (realizada em média aos 28 dias) e nem às cinco semanas de idade, mas afetou significativamente os pesos corporais de 6 a 11 semanas, com aumentos de pesos para endogamia variando de 0 a 10% e diminuições do desempenho após este nível. Nas características de carcaça e abate, o efeito foi pequeno, com uma tendência geral de decréscimo com o aumento do coeficiente de endogamia, o mesmo sendo verificado com o rendimento de carcaça. Estes resultados demonstram a importância do controle dos níveis de endogamia em coelhos, pois, mesmo quando mantidos abaixo dos 10%, podem afetar significativamente o desempenho produtivo.</p>

In degree incest negative influence of inbreeding is established on sheep's productive qualities in comparison with contemporaries with inbreeding in a degree of a close and moderate alliance. The system of a coupling of the wombs is developed, excluding inbreeding depression on productive qualities of animals and allowing to carry out repairs a livestock in a small population due to own reproduction

Research of the peculiar features of correlation parameter of production indices of 870 mongrel inbred sheep with the various inbreeding coefficients was realized in the conditions of the Republic of Belarus. In course of study there was stated the one-sided influence of inbreeding on phenotypic indices of pair, individual and cumulative pair correlation genetic correlations of sheep productivity. The majority of them were the statistically authentic values with P less than 0,1 - 0,001. It was stated that coefficient variability of genetic correlation of wool productivity rendered influence on sheep inbreeding degree among which there were marked off animal units with inbreeding in degree of consanguinity with the coefficients of higher statistical confidence (with P less than 0,01 - 0,001) than animal units with degrees of close or low relationship and outbred animal units - (P less than 0,1 - 0,01). The majority of ewe productive quality correlation factors with a different inbreeding degree proved to be positive and authentic and could be used for an estimation of correlations between traits in selection process for population perfection