Estimation of genetic parameters and genetic trends for pre-weaning traits in Zel sheep

The objective of the present study was to estimate genetic parameters for weight, growth traits and Kleiber ratio in Zel sheep. Genetic and environmental (co)variance components were estimated using 1,664 records of Zel lambs collected during a seven-year period (2003-2009) in the Shirang breeding station, Golestan province, Iran. The traits under consideration were birth weight (BW), weaning weight, average daily gain and Kleiber ratio from birth to weaning. (Co) variance components and corresponding genetic parameters were estimated using univariate analysis fitting by six different animal models through restricted maximum likelihood (REML) method. The suitable model for each trait was determined based on Akaike information criterion (AIC). The estimated heritability of the birth weight, weaning weight, average daily gain and Kleiber ratio were 0.672± 0.146, 0.304± 0.086, 0.397± 0.088, and 0.134± 0.016, respectively. The estimated genetic trends for birth weight, weaning weight, average daily gain and Kleiber ratio, were -0.04824, 0.00062, -0.00062, and 0.04559, respectively.