Cama de frango e suplemento à base de microbiota ruminal em dietas de novilhas leiteiras: desempenho produtivo e avaliação econômica

Abstract

This research was carried out to evaluate the performance of dairy heifers fed with broiler litter (BL) and ruminal microbiota supplement (RMS). Twenty heifers, crossbred Holstein x zebu, with average weight and age of 276 kg and 13,8 months, respectively, were used. The animals were randomly allotted to a 2x2 factorial scheme: two levels of BL (15 and 30% in the diet dry matter) and RMS (0 and 10 g/heifer/day), in a completely randomized design, with five replications. The feed intake, weight gain, feeding efficiency and costs were evaluated, and an cash flow for feedlot and grazing systems was simulated. The intake of dry matter, organic matter, crude protein and neutral detergent fiber were not different for BL and RMS. Daily weight gain was higher for heifers fed diet with 15% BL and 10 g of RMS (1.13 kg), in relation to 15%BL without RMS (0.85 kg), but without differences for animals receiving only 30% BL or SMR (1.09 and 0.97 kg). There were no differences in dry matter and neutral detergent fiber conversions, but there was an interaction between BL and RMS levels and efficiency of crude protein utilization. Cost/benefit ratio was better for the 30% BL level, without RMS. Simulated cash flow showed that the feedlot system was economically more advantageous than grazing system, for the condition of this work.