Performance of Arsi-Bale sheep fed urea treated maize cob as basal diet and supplemented with graded levels of concentrate mixture.

The experiment was conducted using 20 yearling intact male Arsi-Bale sheep with a mean body weight of 20.56 ± 0.45 (mean ± SD) to investigate the performance and economic benefit of graded levels of concentrate supplementation to urea-treated maize cob (UTMC)-based diet. The experiment consisted of 7 days of digestibility trial and subsequent 90 days of feeding trial. Before the commencement of the experiment, sheep were vaccinated against common infectious diseases, dewormed, and disinfected against internal and external parasites, respectively. The experimental design was randomized complete block design. The sheep were grouped into five blocks of four animals based on their initial body weight, and one animal from each block was randomly assigned to one of the four treatments. The treatments included ad libitum feeding of UTMC (T1) and supplementation with a concentrate mixture composed of wheat bran (WB) and noug seed cake (NSC) in 2:1 ratio, which were offered at 150 g (T2), 250 g (T3), and 350 g (T4) DM/head/day. The CP content of the UTMC was 9.3% on DM basis. The daily DM intake of UTMC was higher (P < 0.001) for T4 (614.6 g) compared to T1 (505.1 g), T2 (538.9 g), and T3 (590.3 g). Total DM intake was higher (P < 0.001) for supplemented treatments T2 (688.4 g), T3 (844.1 g), and T4 (966.9 g). Supplementation did not improve (P > 0.05) digestibility of DM, OM, NDF, and ADF, except CP digestibility which was significant (P < 0.001) across treatments. Supplementation increased (P < 0.001) final body weight (FBWT), feed conversion efficiency (FCE), and average daily weight gain (ADG). The average daily gain (ADG) was highest (P < 0.001) in T4 (80.8 ± 7.74 g/day) followed by T3 (33.3 ± 7.74 g/day) and T2 (23.1 ± 0.95 kg) whereas the un-supplemented animals lost about 9.2 g/day. The highest total return, net income, and marginal rate of return were observed in higher level supplemented sheep than the control. Therefore, T4 improved biological performance and marginal rate of return than the other treatments and can be considered as better alternative feed supplement in UTMC-based feeding of Arsi-Bale sheep in Ethiopia.