Performance of Rambouillet crossbred grazing on alpine pastures of Pakistan under transhumant system.

Abstract

The two studies reported performance of Rambuoillet crossbreds (ewes and rams) with local sheep breed Khutta under grazing system of transhumant. Analysis of variance revealed that Rambouillet crossbred ewes were initially 16 percent heavier than their age mates of local breed. Within each genotype, ewes <1 year old were significantly (p<.01) lighter than >1, >2, >3 and >4 years old. Although Rambouillet crossbred ewes were 17 percent heavier, pattern of differences in BW of various age groups of both genotypes at the start of movement for grazing toward alpine pastures of northern areas (First recording) was almost the same. However ewes of local genotype-Khutta lost more BW (6.7 kg) during movement back to low land areas (Second recording) compared with Rambouillet crossbred ewes (4.1 kg). BW of Rambouillet crossbred ewes remained higher than local ewes even during winter (+17 %) and summer (+19 %). Analysis of variance further revealed that BW of >4 years old ewes of both genotypes were 30 and 38 percent higher than their <1 year old age mated. A significant interaction (p<0.05) was also observed between age and reproductive cycle with effects on BW of both genotypes. Rambouillet crossbred ewes were found more prolific with a fertility rate 85 percent compared with 80% in Khutta local breed. Survival rate among Rambouillet crossbred lambs was 93.4% compared with 84.3 percent in locals. Rams flushed with concentrate before breeding season differed in efficiency of weight gain. Minimum feed required for each kg weight gain was 8.1 kg in group 2 compared with 9.5 and 10.7 in groups 3 and 1 with significant differences (p<.05). Improvement in BCS was higher (45%) in rams of group 3 compared with 31.2 and 18% for groups 2 and 1, respectively. Feed required per unit of improvement in BCS was 1.4 kg in group 3 followed by 1.8 and 4.8 in groups 2 and 1. Analysis of variance revealed that cost of weight (Rupees per Kg) was lowest (153) in group 2 compared with 217.8 and 188.1 in groups 1 and 3, respectively.