57 Evaluation of Virginiamycin Inclusion in the Diets of Feedlot Steers: Interplay between Rumen pH and Liver Health

Abstract In the beef cattle system, liver abscesses are most common abnormality and leading cause for condemnations at slaughter. Virginiamycin (VM) has been used to prevent sub-acute ruminal acidosis (SARA) subsequently control abscess incidence. This study observed interrelationship between VM inclusion (240 mg/hd/d), pH dynamics, hepatic blood metabolites over a 150-d feeding trial. Housed in Calan gate 120 Angus crossbred steers (291 ± 28 kg) were randomly assigned 1 of 6 dietary treatments: no (T000); last 50 d (T001); 100 (T011); first (T100); (T110); 150 (T111). Steers orally administered 2 indwelling smaXtec rumen temperature recording boluses on -4 84. On -7, 28, 56, 84, 112 140, samples collected via jugular venipuncture all plasma analyzed concentrations albumin, alkaline phosphatase, direct bilirubin, total gamma-glutamyl transferase, protein using an automated analyzer (Carysta High Volume Chemistry Analyzer; Zoetis). Haptoglobin (HPT) was measured following colorimetric method based peroxidase activity. Data random coefficients model with pen as effect animals within treatment subject. Results indicated that did not convalesce function (P > 0.05), but HPT had increased 84 excluded treatments (42.75 vs. 93.25 mg/L). Comparatively, T111 tended have less time under 5.8 (2.50 h/d) when compared T001, T100, T000 (5.27; 4.94; 4.23 h/d, respectively; P = 0.107). Therefore, should be fed from growing phase slaughter capture full potential product animal health status.