ارتباط بين صفات رشد و لاشه درگوسفندان لري بختياري

Relationship Between Growth and Carcass Traits in Lori-Bakhtiari Sheep

Data of growth (birth weight n=6240; weaning weight, n=5795; 6 month weight, n=4599) and carcass traits of Lori-Bakhtiari lambs obtained from Lori-Bakhtiari Sheep Breeding Station were used to study parameters as well as the relationship between traits. The lambs were weaned at 90±5 days of age. After post-weaning period at (I93 days of age), 454 Jambs were slaughtered from which a number of 264carcasses were physically analyzed. Genetic parameters were estimated via multivariate animal model, using a restricted maximum likelihood approach. Direct heritabilities for birth weight weaning weight. 6 month weight, average daily gain from birth up to weaning, average daily gain from birth to 6 months of age, 3 and 6-month, Kleiber slaughter weight, carcass weight and weights of carcass lean, fat, bone and fat-tail were 0.32, 0.22, 0.29, 0.20, 0.28, 0.14, 0.26,0.32,0.26,0.41,0.27,0.30 and 0.33, respectively. Maternal heritabilities of preweaning traits were low, with an exception for birth weight The genetic correlations between pre-weaning and post-weaning traits were moderate to high. The phenotypic and genetic correlations among growth and carcass traits were estimated as positive, ranging from 0.32 to 0.98. The phenotypic and genetic correlations between carcass traits ranged from low to high. The genetic correlation between lean and fat weights was positive but low.