اثر هم‌خونی بر کاهش وزن پشم در بره‌های لری ‌بختیاری

The aim of this study was to estimate inbreeding coefficient and its impact on wool performance in Lori-Bakhtiari sheep. In this research, wool weight records of 6234 lambs born from 273 rams and 1924 ewes were used. The data were collected at Shahrekord Sholi station during 1990-2010. In total pedigree, 1764 animals were inbred. Averages of inbreeding coefficient for total and inbred population were estimated at 1.02 and 2.32 respectively. The inbreeding effects reduced wool weight performance approximately 4.2±1 g for each percentage of increase in inbreeding. Increasing 1% of inbreeding coefficient of male and female lambs was respectively accompanied with decreasing 5±1 and 3±1 g in wool weight. This decreasing was 4.6±1 and 2±1 g for single and twine lambs respectively. Annual trend in inbreeding coefficient for total and inbred population were 0.098±0.01 and -0.72±0.1 kg respectively that was statistically significant (P<0.01). Applying a designed mating system like crossbreeding and supervised using of elite rams could be a suitable method to avoid inbreeding depression via keeping the level of inbreeding under control.