The effect of inbreeding on birth weight of Saanen goat kids

Inbreeding is practically impossible to avoid in the livestock breeding and it is particularly hard to keep it under control in the populations under a high selection pressure. The main reason is excessive usage of genetically superior sires. The study aimed to examine the effect of inbreeding on the birth weight of Saanen goat kids under the framework of the genetic animal model for maternal traits. All growth traits until weaning are not only influenced by the genes of the individual for growth (direct additive genetic effect), but also by the maternal genetic composition (indirect maternal genetic effect) and by nongenetic environment provided by the dams (permanent environment effect). Ministry of Agriculture provided all the data used in the study. The birth weight (BW) was available for the 17990 among a total of 21118 animals in the pedigree. The estimated ratios of variance components for direct genetic effects, indirect maternal genetic effects, maternal permanent environment, and herd were 0.127, 0.026, 0.163, and 0.373, respectively. According to the estimated coefficient of inbreeding (F), 60% percent of the animals in the pedigree were inbred to some degree. However, the majority of the inbreds (81%) had a really long path (F0.20) was determined in only 5% of the inbreds. These frequencies, in addition to the average F (0.042 for inbreds and 0.025 for the entire population) implicate that mating of closely related individuals in this population is under control. Inbreeding did not statistically affect BW (= 0.0001 ; P>0.05) but generalization of this effect should be performed with great caution because inbreeding depression could have been masked by positive response to selection and imbalanced non-experimental data.