Growth rate and body composition of lambs receiving agricultural wastes as grass substitutes

Abstract

An experimental study was carried out to investigate the effect of grass substitution with agricultural industrial wastes on the growth rate and body composition of lambs. This study used 20 male thin-tailed lambs aged 3 months, weighed 13.37 ± 1.36 kg (CV = 10.21%). The lambs were fed diets in the form of pellets, with the fibrous feedstuff and concentrate balance of 40:60. The lambs were allocated into a completely randomized design with four treatments of fibrous feedstuff and five replications. The fibrous feedstuff treatments applied were T0: 100% napier grass; T1: 50% napier grass +50% corn cobs 50% T2: 50% napier grass+50% bagasse; and T3: 50% napier grass+50% peanut shells. The parameters observed included dry matter intake (DMI), crude protein intake (CPI), total digestible nutrients (TDN) intake, body weight gain (BWG), feed conversion ratio (FCR) and body composition of the lambs. The results showed that the replacement of grass with agricultural industrial waste had a significant effect (P<0.05) on DMI and CPI. The highest DMI was found at T3 (781 g/day), while T0, T1 and T2 were not significantly different (721 g/day on average). The highest CPI was obtained at T0 (84 g/h) followed by T3 (81 g/h), T1 (77 g/day) and T2 (74 g/day). However, there was no significant effect (P>0.05) of treatment on TDN intake (averaged 434 g/day). The diet treatment had a significant effect (P<0.05) on BWG and FCR. Diet T3 and T1 produced the highest BWG (94 and 79 g/day) and the lowest FCR (9.08 and 9.33). Diet treatment had no significant effect (P>0.05) on body composition of the lambs (the average of water, protein and fat content were 58.43%; 9,85; 20,88%, respectively). It can be concluded that agricultural industrial waste can be used as a substitute for napier grass at the level of 50%.