A study was conducted to determine effect of supplementation with isonitrogenous level of concentrate mixture (CM; 33% noug seed cake (NSC) and 67% wheat bran (WB)), alfalfa, lablab, and Leucaena leucocephala (LL) on feed intake, digestibility, daily body weight gain (ADG) and net return of sheep kept on Rhodes grass hay (RGH) basal diet. Twenty four yearling male DorperÃ—Afar F1 crossbred sheep were used in completely randomized block design blocked by initial body weight into 6 blocks of 4 animals and allocated to one of the treatments. Treatments were RGH fed ad libitum to all treatments plus 300 g/day CM (T1), 286 g/day alfalfa hay (T2), 326 g/day lablab hay (T3) and 299 g/day LL hay (T4). The study contained 90 days feeding and 7 days digestibility trials. The CP, NDF and ADF contents of RGH was 11, 77 and 51%, respectively. The CP contents of NSC, WB, alfalfa, lablab and LL were 32, 17, 23, 20 and 22%, respectively. Among the supplements alfalfa and lablab had relatively higher NDF and ADF levels. Total DM intake differed among treatments and was greater (P<0.05) for T2 and T4 than T3, and values for T4 was greater than T1 (P<0.001) (715, 727, 682 and 809 g/day for T1, T2, T3 and T4, respectively). The CP intake was 103, 110, 92, 130 (SEM = 5.83) and was in the order of T4 > T1 = T2 > T3 (P<0.05). Apparent DM digestibility ranged from 62-66% and was lower (P<0.05) for T2 than T1 and T4, while values for T3 was similar (P>0.05) with all other treatments. The apparent digestibility of CP was greater for T1 than T2 and T3, but values for T4 was similar with the other treatments (82.3, 78.7, 78.3 and 80.4 (SEM = 0.02) for T1, T2, T3 and T4, respectively). ADG was 65, 45, 40 and 69 g/day (SEM = 8.36) for T1, T2, T3 and T4, respectively and the values were greater (P<0.05) for T1 and T4 as compared to the other two treatments, while other mean values were similar (P>0.05). The net return in the currents study was 836, 797, 888 and 982 ETB. Thus, based on biological performance and net return, T4 and T1 outweighs other treatments. However, all supplements used in this study induced favorable ADG and thus can be employed in feeding systems depending on their availability and relative cost.
Keywords: Isonitrogenous, crossbred, digestibility, ADG, RGH, DM, SEM