Genetic analysis of growth traits and Kleiber ratio in Moghani sheep breed

In this research, records of growth traits of Moghani sheep breed collected during1996 to 2011 in Moghan breeding station, Ardabil were used for genetic analysis. Variance components and genetic parameters were determined for each trait using Maximum Likelihood procedures and six various animal models using WOMBAT software. The traits were birth weight (BW: 7028 records), weaning weight (WW: 5695 records), weight at age 6 months (6MW: 4954 records), weight at age 9 months (9MW: 2322 records), yearling weight (YW: 1872 records), average daily gain and Kleiber ratio in four time from birth to weaning (ADG1 & KR1), average daily gain and Kleiber ratio was from weaning to age 6 (ADG2 & KR2), average daily gain and Kleiber ratio from age 6 to age 9 (ADG3 & KR3), and average daily gain and Kleiber ratio from age 9 to 12 (ADG4&KR4). Pedigree structure was analyzed by CFC software. Classified effects included in the model were gender, type of birth, birth mount and birth year and age of dams (as covariate effect). Based on six models, the effect of direct genetic, maternal effect, the effect of maternal permanent environment, the direct additive genetic covariance, maternal and residual effect were estimated. The most suitable model for each trait was determined based on Akaike information criterion (AIC) test. The heritability estimates were 0.007, 0.024, 0.009, 0.181, 0.076, 0.021, 0.120, 0.018, 0.062, 0.082, 0.230, 0.017 and 0.056 for BW, WW, 6MW, 9MW, YW, ADG1, ADG2, ADG3, ADG4, KR1, KR2, KR3, and KR4, respectively. Genetics trends of the traits were -0.00014, 0.00213, 0.00054, 0.0345, 0.0058, 0.0184, -0.0244, 0.0338, 0.0249, 0.0009, - 0.0055, 0.002 and 0.0009, respectively. The results of this study showed that, except for 9MW trait with single trait analysis method, no particular genetic trend was found for the other traits over the 15 years.