Níveis de proteína bruta em suplementos multiplos para novilhas nelore em pastejo na época seca

Abstract

It was evaluated the effect of levels of crude protein supplement on performance, intake, digestibility and microbial efficiency. Forty Nelore heifers, with an initial average age of eight months and an initial average weight of 230 + 3,39 kg, were used. The evaluated supplements were: mineral mix provided ad libitum (MM), supplements containing 10%, 20%, 30% and 40% crude protein (CP), representing the treatments PB10, PB20, PB30, PB40, respectively. It was observed a higher final body weight and weight gain for supplemented animals compared to non-supplemented (P<0.10). The intake of all nutrients were higher (P <0.10) for supplemented animals compared to non-supplemented. The crude protein intake had increased linearly with increasing levels of CP in supplements. The digestibility of DM, OM, CP and TDN were higher (P<0.10) in supplemented animals compared to non-supplemented. There was a quadratic effect on CP digestibility with increased levels of CP in supplements. The production of microbial nitrogen (N mic), serum urea nitrogen (NUS) and reason urea nitrogen in the urine/creatinine nitrogen (NUU/Ncre) were higher (P<0.10) for supplemented animals. Quadratic effect was observed on production of Nmic, microbial efficiency (Emic), NUS and NUU/Ncre with increased levels of CP in multiple supplements. The multiple supplementation provides higher weight gain and final body weight in the period after weaning from Nellore females.