Bio-economic assessment of sheep supplementation in marandu palisadegrass pastures

Abstract

Goal was to evaluate the effect of mineral and/or energy-protein supplementation on intake, behavior, production response, pH, rumen ammonia and production cost of sheep. Twenty female lambs and five rumen-cannulated lambs were used to test supplementation effects on weight gain and nutritional characteristics, respectively. Treatments evaluated were: mineral mixture, supplement with 20 and 25% of crude protein offered at 0.5 and 1.0% of body weight. Supplementation at 1.0% of body weight reduced forage intake. Average daily gain were: -58.33, -1.07, -9.53, 19.27 and 34.73 g day-1 per animal, for mineral mixture, supplements with 20 and 25% of crude protein supplied at 0.5% of body weight and 20 and 25% crude protein provided at 1.0% of body weight, respectively. Rumen pH for all supplements was maintained above 6.20. Values of rumen ammonia nitrogen were 5.10, 9.48, 11.54, 17.51 and 22.45 mg dL-1 for supplements: mineral mixture, 20 and 25% of crude protein provided at 0.5% of body weight and 20 and 25% of crude protein supplied at 1.0% of body weight, respectively. The best economic return was obtained with the supplement 25% of crude protein provided at 1.0% of body weight. _____________ RESUMO: Objetivou-se com este estudo avaliar o efeito da suplementação mineral e/ou proteica energética no consumo, comportamento, resposta produtiva, pH e amônia ruminais e custo de produção de ovinos. Utilizaram-se 20 borregas e cinco borregos canulados no rúmen para avaliar os efeitos da suplementação sobre o ganho de peso e características nutricionais, respectivamente. Avaliaram-se os suplementos mistura mineral e suplementos com 20 e 25% de proteína bruta ofertados a 0,5 e 1,0% do peso corporal. A suplementação na proporção de 1,0% do peso corporal reduziu o consumo de forragem. Os ganhos médios diários foram de –58,33; –1,07; –9,53; 19,27 e 34,73 g animal dia-1, para os suplementos mistura mineral, 20 e 25% de proteína bruta fornecidos a 0,5% do peso corporal e 20 e 25% de proteína bruta ofertados a 1,0% do peso corporal, respectivamente. O pH para todos os suplementos esteve acima de 6,20. Os valores de nitrogênio amoniacal ruminal foram de 5,10; 9,48; 11,54; 17,51 e 22,45 mg dL-1 para os suplementos mistura mineral, 20 e 25% de proteína bruta fornecidos a 0,5% do peso corporal e 20 e 25% de proteína bruta fornecidos a 1,0% do peso corporal. O melhor retorno econômico foi obtido com o suplemento 25% de proteína bruta a 1,0% do peso corporal.