Objetivou-se determinar o consumo voluntário, a digestibilidade da MS, MO e dos nutrientes (PB, EB, FDN, FDA, CT, CNF e EE) e o balanço de nitrogênio de dietas contendo feno de maniçoba (Manihot glaziovii Muell. Arg.). Vinte quatro cordeiros Santa Inês com média de 28,62 kg PV foram distribuídos em um delinemento completamente casualizado e alimentados com rações contendo 20, 40, 60 ou 80% de feno de maniçoba. Os consumos médios de MS, MO, PB e CT foram 1,24; 1,12; 0,20 e 0,82 kg/dia, respectivamente, e os consumos médios de EM, FDN, FDA, EE e CNF foram, respectivamente, 2,78 mcal/dia; 401,01; 215,50; 83,42; 426,62; e 126,10 g/dia. Os coeficientes de digestibilidade de MS, PB e EB foram, respectivamente, 60,22; 56,16 e 61,90%, e os de FDN, FDA, CT e CNF, 44,73; 54,63; 61,50 e 78,41%, respectivamente. O balanço nitrogenado foi positivo, com média de 7,20 g N/kg MS/dia, e o nitrogênio aparentemente retido representou 21,45% do N ingerido. A inclusão de 80% de feno de maniçoba na dieta não afetou o consumo de MS, no entanto, reduziu a digestibilidade aparente dos nutrientes da dieta.

The objective was to determine the voluntary intake and digestibility of DM, OM and nutrients (CP, GE, NDF, ADF, CT, NSC and EE). And nitrogen balance of diets containing maniçoba maniçoba (Manihot glaziovii Muell. Arg.) hay Twenty-four Santa Ines lambs, average 28.62 kg LW were allotted to a completely randomized design and fed diets containing 20, 40, 60 e 80% of maniçoba hay.The mean intakes of DM, OM, CP and CT were 1.24, 1.12; 0.20; and 0.827 kg/d, respectively, and the mean intakes of ME, NDF, ADF, EE and NSC were, respectively, 2.78 mcal/kg, 401.01, 215.50, 83.42, 426.62, and 126.10 g/d. The apparent digestibility for DM, CP, and CE were respectively, 60.22, 61.28, 56.16, 61.90, and for NDF, ADF CT and NSC were, respectively, 44.73, 54.63, 61.50, and 78.41. The nitrogen balance was positive, with mean of 7.20 g N/kg DM/d, and the apparently retained nitrogen represented 21.45% of ingested N. The inclusion of 80% of maniçoba hay in the diet did not affect the DM intake, however, the nutrient apparent digestibility in the diet decreased as maniçoba hay increased in the diet.

Avaliou-se o desempenho de cordeiros alimentados com dieta completa formulada com diferentes proporções de feno de maniçoba. Foram utilizados 32 animais Santa Inês machos, não-castrados (idade inicial de 70 dias e peso vivo de 16,02±2,37 kg), distribuídos em delineamento inteiramente casualizado, com quatro tratamentos e oito repetições. As dietas foram constituídas de concentrado e feno de maniçoba (FM) nas proporções de 20, 40, 60 e 80%. As proporções de feno na dieta não influenciaram os consumos de MS, PB e CT, cujas médias diárias foram 1,214; 0,201 e 0,816 kg, respectivamente. Os níveis de feno tiveram efeito linear positivo sobre o consumo de FDN e efeito linear negativo sobre o consumo de EM e CNF. O ganho de peso diário foi afetado pelos níveis de feno na dieta, apresentando médias de 290,84; 293,62; 253,35 e 208,48 g, respectivamente, para as dietas com 20, 40, 60 e 80% de feno de maniçoba. As dietas influenciaram a conversão (Y = 3,332+0,028x) e a eficiência alimentar (Y = 0,280,0013x). Pela análise econômica, observaram-se relações custo:benefício de 1,49; 1,57; 1,69 e 1,84 para os níveis de 20, 40, 60 e 80% de feno de maniçoba na dieta. O custo operacional efetivo por quilograma de carcaça produzida foi de R$ 3,68; R$ 3,49; R$ 3,23 e R$ 2,98, respectivamente, para as dietas com 20, 40, 60 e 80% de feno. A inclusão de 80% de feno de maniçoba em dietas completas possibilitou a obtenção de desempenho satisfatório dos cordeiros e melhor retorno financeiro.

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.