Supplementation of grazing suckling beef calves receiving different energy sources ; Suplementação de bezerros de corte lactentes em pastejo com diferentes fontes energéticas

The aim of this study was to evaluate the effect of different energy sources - corn, sorghum, and wheat bran - on performance, intake, digestibility, and nitrogen utilization efficiency of beef calves subjected to creep feeding. Thirty-four calves (12 males and 22 females) with initial age and weight of four months and 108±3.9 kg, respectively, were used in a randomized-block experimental design with four treatments and two blocks (males and females). Treatments were control (MM), a mineral mixture ad libitum; corn (C); corn + sorghum (C+S); and corn + sorghum + wheat bran (C+S+WB). Supplements contained approximately 20% crude protein (CP), and were fed in the amount of 0.5% of body weight. Supplemented animals had higher performance (P < 0.05) when compared with those on treatment MM. Supplementation increased (P < 0.05) the intakes of dry matter (DM), organic matter (OM), crude protein (CP), neutral detergent fiber corrected for ash and protein (NDFap), non-fibrous carbohydrates (NFC), digestible neutral detergent fiber (dNDF), and digestible organic matter (dOM). The digestibility of NFC was higher (P < 0.05) in the supplemented treatments. The C+S and C+S+WB treatments provided increased digestibility (P < 0.05) of OM, CP, and NDFap. The synthesis of nitrogen compounds was higher (P < 0.05) in animals on treatment C as compared with those on the other supplemented treatments. Animals on treatments C+S and C+S+WB had higher (P < 0.05) nitrogen utilization efficiency compared with those on the other treatments. Concentrate supplementation improved the animal performance. The use of other energy sources (sorghum or wheat bran) in association with corn is recommended for suckling calves. ; O objetivo deste trabalho foi avaliar o efeito de diferentes fontes energéticas, milho, sorgo e farelo de trigo, sobre o desempenho, o consumo, a digestibilidade aparente total dos constituintes da dieta e a eficiência de utilização dos compostos nitrogenados em bezerros de corte submetidos ao creep feeding. ...