Environmental and genetic effects on conformation, precocity and musculature traits at weaning in Suffolk lambs

The aim of this study was to investigate and estimate the influence of type of lambing, age at weaning and age of the dam at lambing on conformation (C), precocity (P), musculature (M), and to estimate the heritability coefficients and genetic correlations among these traits, in Suffolk lambs. For the analysis of environmental effects and genetic parameters, the contemporary group was considered as a fixed effect, whereas covariates included the linear effects of type of lambing and age at weaning and the linear and quadratic effects of the age of dam at lambing. Lambs born as singletons received the highest scores in all three studied traits when compared to those from multiple lambings. Similar effects were observed for late-weaning lambs. 4-5 years old dams promoted the highest scores for their lambs. Heritability coefficients were 0.15, 0.18, and 0.16 for C, P, and M, respectively, indicating possibility of genetic gain through individual selection. Estimates of genetic correlation between these traits were positive and of high magnitude, varying from 0.83 to 0.95, showing that the studied traits are controlled, in part, by the same sets of genes and, therefore, there is the possibility of correlated response.