investigation of inbreeding in baluchi sheeps of abbasabad breeding station

in this study 21721 pedigree records of iranian baluchi sheep registered during 30 years (1979 to 2008) at abasabad breeding station were used to estimate pedigree completeness level, inbreeding and average relationship coefficients of animals. during the studied years pedigree completeness level has a positive trend with the most recent cohort of lambs born in 2008 having pedigrees with 6.2 equivalent generations of known ancestors. also, average inbreeding coefficient increased in these years and linear regression of inbreeding on year of birth resulted in an estimated rate of inbreeding of 0.15 %/yr. inbreeding of number 2 flock was higher than that was in number one (p<0.001). average coefficient of inbreeding in active animals was 1.95%. the average coefficients of relationship between active animals were computed to predict the future level of the inbreeding coefficient. the average coefficients of relationship between rams, between ewes and between rams and ewes in live breeding animals were 4.12, 2.50, and 2.44% respectively. considering the scatter plot of average relationship coefficients of a new born ram to active animals of the same flock and different flock, two flocks have become closely related populations, and calculation of the average relationship coefficients of rams with animals of each flock is necessary to make a decision about exchange of rams between flocks