ABSTRACT:
The present study evaluated the effect of increasing levels of wet brewery residue (WBR) as a source of roughage on nutrient intake, performance and ingestive behaviour in lambs finished in confinement. Thirty-two uncastrated male lambs were used, weaned at 50 days of age. The treatments comprised increasing levels of WBR as roughage in the diet: 31, 44, 57 and 70%, on a dry-matter. The concentrate consisted of disintegrated corn, soybean meal, calcitic limestone and mineral salt. There was a quadratic effect (P ≤ 0.05) from the increasing levels of WBR on the intake of DM, OM, CP and TCH. The intake of EE, NDF and ADF increased linearly (P ≤ 0.01), while TDN intake showed a linear reduction (P < .0001) for increases in the level of WBR. There was a quadratic effect (P ≤ 0.010) on the average daily weight gain (ADG) from the addition of WBR to the diet. The time spent on feeding and rumination (P ≤ 0.05), expressed in minutes, showed a linear increase. Feeding rate for DM showed decreasing linear behaviour (P ≤ 0.006), while NDF rumination rate showed increasing linear behaviour (P ≤ 0.013) due to the increased levels of WBR in the diet. There was a linear increase in the time spent on each feeding activity (P ≤ 0.007) with the increase in WBR in the diet. Maximum weight gain is achieved when 46.9% WBR is used as a source of roughage in the diet, and this level can be recommended for terminating lambs in confinement.
Key words:
agro-industrial by-products; sheep; weight gain