Suplementação de vacas leiteiras com Virginiamicina em dietas à base de cana-de-açúcar

Abstract

The objective of this study was to evaluate the use of Virginiamycin in sugarcane-based diets on performance data of dairy cows and apparent digestibilities of nutrients. Twenty crossbred F1 (Holstein x Gir) cows were used, averaging 80 ± 49 days of lactation, average daily milk production of 27 ± 3.8 kg and mean body weight of 588 ± 68 kg. In a Switch Back Reversal trial design, with three experimental periods of 35 days each, being 7 days of data collection and samples. The experimental diets were balanced according to NRC (2001) to be isoproteic (16, 0% PB) and isoenergetic (68, 4% NDT). The control group received the diet without inclusion of MV, whereas the treatment group was supplemented with MV added to the concentrate formulation at the dose of 300 mg/cow /d. There was no difference in dry matter and nutrient intake. The group supplemented with MV had higher apparent digestibility of the protein and tendency to increase the digestibility of NDF and diet dry matter. Milk production and composition values were not influenced by addition of MV as well as faecal pH. No differences were observed in plasma glucose and NUP concentrations. The addition of MV increased the relative synthesis of microbial protein.