Nutrient utilization and production performance of lambs grazing on community rangeland with and without concentrate supplementation

Male lambs (20), 2_3 months age and weighing 10.15±0.0.432 kg were selected and randomly divided into 2 groups of 10 each (G1and G2). Lambs in both the groups were grazed on natural rangeland from 07.00 to 18.00 hr, followed by night shelter in the animal shed. G2 lambs were maintained on sole grazing while lambs in G1, in addition to grazing received concentrate mixture @ 1.5% of their body weight. The mean biomass yield of the community rangeland was 13.8 q DM/ha. The roughage intake was similar between supplemented (G1) and non-supplemented (G2) group. However, there was significant difference in the total DMI, DCP and ME between G1 and G2. The digestibility of DM, OM, CP, NDF and ADF was higher in G1 as compared to G2. After 90 days of feeding, the body weight of lambs in G1 and G2 reached 21.64 and 18.74 kg, respectively. The average body weight gain and average daily gain in G1 was higher than that in G2 (8.63 kg and 95.9 g). The wool yield (g) and fibre characteristics, viz. hetro medullation (%), staple length (cm) and crimp per centimeter did not differ between the two groups. However, diameter (micron) and hairy medullation (%) were higher (P0.05) in G1 than that in G2. The cost: benefit ratio of the supplementary feeding was 1: 1.42. It is concluded from this study that the biomass yield of the community rangeland in semi-arid region of India is low and insufficient to meet the nutrient requirement of weaner lambs. However, concentrate supplementation @ 1.5% of the body weight to the lambs during this active phase of growth enhanced their growth rate for cost effective mutton production.