Inbreeding and Its Effects on Body Weight,Kleiber Ratio, Body Measurements, Greasy Fleece Weight and Reproductive Traits of Makooei Sheep Breed

A pedigree file consisting of 5860 individuals, 167 sires and 1582 dams collected at Makooei sheep breeding station (MSBS) during a period of 24 years (1990 to 2013) was used to calculate the inbreeding coefficients to reveal any probable effects of inbreeding (F) on the studied traits. The studied traits were classified to the five main groups including body weight, Kleiber ratio, body measurements, greasy fleece weight and reproductive traits. The inbreeding coefficient among the individuals ranged from 0 to 25% with an average of 0.33%, and ranged from 0 to 25% among the ewes with an average of 0.21%. Fluctuations in individual and maternal inbreeding were observed in the period under study. The average generation interval was calculated as 3.6 years. The effective population size of the flock was 51.8 animals. The rate of inbreeding was 0.08% per year and 0.53% per generation. Six different models were applied and likelihood ratio test (LRT) was used to select the appropriate model. Based on the LRT, model II was selected as appropriate model for growth, greasy fleece weight at 6 months of age and kleiber ratio traits. The traits related to the live body weight were affected negatively (P