Carcass characteristics of sheep fed with castor bean hulls in replacement of tifton 85 hay Características de carca a de ovinos alimentados com casca de mamona em substitui o ao feno de capim Tifton 85

Castor bean hulls (CBH), co-products of castor oil extraction, are high in dry matter (DM) and fiber and are emerging as alternative roughage in sheep feed. This could reduce feed costs since other sources of roughage can be more expensive. The effects of replacing Tifton 85 hay with CBH at 0, 33, 66 and 100% in the diet of sheep on the carcass characteristics, weights and yields of retail cuts and carcass measurements were studied. Twenty-eight non-castrated sheep averaging 7 ± 1.4 months of age with an initial weight of 19.5 ± 4.3 kg were slaughtered after 70 days of confinement. There was a linear decline (P ≤ 0.05) in slaughter body weight, empty body weight, hot and cold carcass weight and longissimus muscle area (LMA) as the percentage of dietary CBH increased. A linear decrease (P≤0.05) of the weights of all retail cuts and a quadratic effect (minimum yield of 9.84% with the replacement of 56.9%) of the neck yield were also detected as the percentage of CBH increased. No treatment effects (P > 0.05) on the yield of the other cuts were observed, but there was a linear decline (P ≤ 0.05) in the perimeters of the thorax, leg and rump and the carcass compactness index. Replacing Tifton 85 hay with CBH in sheep diets is not recommended because it decreases the slaughter body weight, cold and hot carcass weight, retail cut weights and morphometric measurements. A casca da mamona, coproduto da extra o do óleo da mamona, por apresentar em sua composi o elevados teores de matéria seca e fibra, surge como fonte alternativa de volumoso na alimenta o de ovinos, podendo diminuir os custos com alimenta o, uma vez que outras fontes s o comercializadas a pre os superiores. Avaliou-se o efeito da substitui o do feno de capim Tifton 85 pela casca de mamona em 0, 33, 66 e 100% na dieta de ovinos sobre as características de carca a, os pesos e rendimentos dos cortes comerciais e a morfometria da carca a. Vinte e oito animais n o castrados, com 7 ± 1,4 meses de idade e peso inicial médio de 19,5 ± 4,3 kg, foram abatidos após 70 dias de confinamento. Houve efeito linear decrescente (P≤0.05) para o peso corporal ao abate, peso de corpo vazio, peso de carca a quente, peso de carca a fria e área de olho-de-lombo, de acordo com os níveis crescentes de substitui o. O decréscimo linear (P≤0,05) no peso de todos os cortes comerciais e o efeito quadrático do rendimento do pesco o (rendimento mínimo de 9,84% quando a substitui o foi de 56,9%) também foram verificados com o aumento percentual da casca de mamona. N o houve efeito (P > 0,05) sobre os rendimentos dos demais