The objective of this trial was to investigate the effect of different dietary ratios of concentrate (C) to ceara rubbertree hay (CRH; Manihot Glaziovii Muell. Arg.) on performance of lambs. Thirty two intact Santa Inês lambs averaging 70 days of age and 16.02±2.371 kg of body weight were fed one of the following four treatments as total mixed rations: 80C:20CRH (diet A), 60C:40CRH (diet B), 40C:60CRH (diet C), or 20C:80CRH (diet D) in a completely randomized design (eight repetitions/treatment). Increasing levels of CRH in the diet had no significant effect on the intakes of dry matter, crude protein, and total carbohydrates which averaged 1.214, 0.201, and 0.816 kg/day, respectively. However, intake of neutral detergent fiber increased linearly while the opposite was observed for intakes of metabolizable energy and nonfiber carbohydrates by increasing the proportion of CRH in the diet. The average daily gain was significantly affected by the different dietary ratios of C:CRH averaging 290.84, 293.62, 253.35, and 208.48 g/d, respectively, for diets A, B, C, and D. Significant linear effects were also observed for feed conversion (Y = 3.332 + 0.028x) and feed efficiency (Y = 0.28-0.0013x) when the proportion of CRH was increased from diet A to diet D. The profit:cost ratio and the cost per kg of carcass averaged, respectively, 1.49, 1.57, 1.69, and 1.84 and R$3.68, R$3.49, R$3.23, and R$2.98 with 20, 40, 60 and 80% of CRH hay in the diet. It can be concluded that the C:CRH ratio of 20:80 (diet D) resulted in satisfactory performance and improved income of Santa Inês lambs.
confinement; feed efficiency; Manihot glazioviiMuell. Arg.; native forage; nutrient intake; sheep
