عملکرد رشد و پرواری بره‌های لریبختیاری، آمیخته‌های رومانف × لری‌بختیاری و پاکستانی × لری‌بختیاری

   This study was conducted to compare the feedlot performance and growth traits of Lori-Bakhtiari (n=39), Romanov × Lori-Bakhtiari (n=38) and Pakistani × Lori-Bakhtiari crossbred (n=12) lambs during two consecutive years. Lambs were weaned at the age of 90 ± 5 days. After weaning and preliminary fattening period, three groups of lambs were fattened for 90 days in the same conditions. The results showed that weaning weight in Romanov × Lori-Bakhtiari crossbred lambs were significantly higher than in Lori-Bakhtiari and Pakistani × Lori-Bakhtiari crossbred lambs. Lori-Bakhtiari and Romanov × Lori-Bakhtiari lambs were not significantly different (P < 0.05) for daily gain, feed intake, feed conversion ratio and final weight of the finishing period. Lori-Bakhtiari and Romanov × Lori-Bakhtiari lambs for daily gain (200 and 184 gr), feed conversion ratio (8.52 and 8.95) and final weight (51.78 and 50.26 kg) of the finishing period were significantly (P < 0.05) higher than in Pakistani × Lori-Bakhtiari crossbred lambs for this traits (47.71 kg, 155 gr and 11.07, respectively). Effect of year in different genetic group on fattening traits was significant (P < 0.05). In each genetic group between male and female lambs for fattening traits was significant differences (P < 0.05), however, between Lori-Bakhtiari and Romanov × Lori-Bakhtiari lambs for fattening traits were not significantly different. Therefore, crossbreeding between Romanov and Lori-Bakhtiari were better than crossbreeding between Pakistani and Lori-Bakhtiari to improve growth and fattening performance.