Estrutura populacional e efeitos da endogamia sobre características de crescimento em ovelhas morada nova

Abstract

Genealogical records of 6,573 animals were used to describe the population structure, evaluate the genetic variability, and estimate the effect of inbreeding on the growth traits of Morada Nova sheep, which included birth weight (BW, n = 4,340), weaning weight (WW, n = 2,308), and pre-weaning weight gain (WG, n = 2,071). The effective numbers of founder and ancestral animals were 105 and 86, respectively; 39 ancestors were responsible for 50% of the genetic variability in this population. The effective sizes for maximum, complete, and equivalent generations were 57.31, 24.02, and 28.74, respectively. The low values obtained for the average inbreeding (0.88%) and average kinship coefficient (0.52%) indicated genetic variability that could be explored by selection. However, these results may be related to the low integrity of the pedigree, which was observed through the number of equivalent generations (1.09). Inbreeding depression was not observed (P<0.05) in the growth traits evaluated.