329 Effectiveness of Virginiamycin Administration on Animal Health and the Observed Impacts on Growth, Development, and Intake Dynamics in Growing and Finishing Calves

Abstract Virginiamycin (VM) is an antibiotic that possesses antimicrobial properties due to its ability block protein synthase in Gram-positive bacteria. It reduces lactic acidosis and the incidence of liver abscesses. Animal growth development brought about because improved ruminal health, animal health welfare. This study evaluated continuous or intermittent provision VM during growing finishing phases on 120 Angus-crossbred steers (291 ± 28 kg) 20 pens equipped with a Calan gate feed system from which animals received (240 mg/d) as follow: no (T000); last 50 d (T001); for 100 (T011); first (T100); (T110); 150 (T111). Data were analyzed using random coefficients model pen effect within treatment subject. The T011 tended (0.075 ≥ P 0.052) have greater carcass, final shrunk body weight compared T110. Empty fat (EBF; %) (0.080 ≤ 0.050) be less consumed regardless period length feeding. Dry matter intake (DMI) was lesser T111 T000, T110 (P 0.028), resulted average daily gain (ADG) difference efficiency = 0.015 0.225, respectively). ADG-adjusted metabolizable energy (aME) content increased by 3.08% T000. indicated supplementation 240 mg whole feeding phase paME, whereas when withdrawn end (T110) can impair DMI ADG.