Feed Intake, Growth, and Carcass Composition of Black Head Somali Sheep Fed On Different Dietary Protein and Energy Levels

Abstract

The experiment was conducted to assess the importance of different levels of dietary protein and energy supplements on feed intake, growth, and carcass composition of Black Head Somali sheep. A randomized complete block design was employed with 5 treatments and 6 blocks.  The average initial weight of experimental sheep was 22.19 ± 0.21 kg. The basal feed was grass hay supplemented with concentrate feed formulated from groundnut cake, brewery-dried grain, and wheat bran. Treatment feeds were formulated to provide different levels of dietary crude protein and metabolizable energy.  The treatment feeds were: T1- Control (8.3 MJ ME / Kg DM and 9.1%d CP), T2 (8.6 MJ ME / Kg DM and 11.5%d CP), T3 (9.1MJ ME / Kg DM and 13% CP), T4 (9.55 MJ ME / Kg DM and 15% CP) and T5 (10.2 MJ ME /Kg DM and 17.5% CP). The experiment lasted for 90 days which was preceded by a two-week adaptation period. Sheep consuming control treatment (grass hay) had higher dry matter intake for grass hay (P<0.01) than the supplemented groups. However total dry matter intake was higher (P< 0.01) with increasing levels of supplementation. Higher total CP intake (TCPI) and total estimated ME intake (TEMEI) were significantly higher (P<0.01) with increasing levels of supplementation. Slaughter body weight, empty body weight, hot carcass weight, and dressing percentage were higher (P<0.01) for the supplemented groups compared to the control. The group with the highest level of protein and energy supplementation (T5) had higher (P<0.01) hot carcass weight, empty body weight, rib eye muscle area, lean meat, and fat weight compared to the other supplemented treatment groups. Bone weight was statistically non-significant for all treatments (P>0.05). The financial return obtained from T5 was 3876 Birr, being higher than the other groups. The marginal rate of return percentage was increasing at a decreasing rate for all treatments except T4.  Treatment 5 with the highest level of energy and protein had the highest return and is recommended for further study to establish the optimum dietary protein and energy levels.