Desempenho e metabolismo ruminal em bovinos de corte em sistema de pastejo no periodo seco do ano recebendo virginiamicina na dieta

Abstract

This study aimed to evaluate the effects of including virginiamycin (VM) in two levels, the proteinenergy supplement for growing beef cattle diet with the tropical grass base in the dry season. Three treatments were evaluated: control treatment, only Mineral Supplement ME - Production - F.10 proteinenergy (SPE); 100 virginiamycin treatment (VM 100) + SPE 108 mg (Phigrow ®) VM/animal/day and treatment virginiamycin 200 (200 MV) + SPE 216 mg (Phigrow ®) VM/animal/day. The variables analyzed were the supplement intake (SI), average daily gain (ADG), biometric measurements and body condition score (BCS) in experiment 1 and the average daily supplement intake (ADSI), ruminal pH, ammonia nitrogen, in situ ruminal degradability of dry matter (DM), acid detergent fiber (ADF) and neutral detergent fiber (NDF) in experiment 2. There was no statistical difference for ADG, SI and biometric measurements (P>0.05), ADG for VM 200 of 0,431; VM 100 of 0.391 and control 0.398 kg/animal/day. There was no significant difference (P>0.05) for ruminal pH, the ammonia concentration and the variables at the in situ degradability of DM, NDF and ADF. The virginiamycin conveyed in SPE for beef cattle grazing can promote changes in consumption did not cause significant effects on the values of ruminal pH and ammonia nitrogen and do not show significant effects on the degradability of DM, NDF and ADF.