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

Autor: Madeline E Rivera, Luiz Fernando Dias Batista, Luis O Tedeschi
Rok vydání: 2022
Předmět:
Zdroj: Journal of Animal Science. 100:28-28
ISSN: 1525-3163
0021-8812
DOI: 10.1093/jas/skac247.052
Popis: In the beef cattle system, liver abscesses are the most common liver abnormality and are the leading cause for condemnations at slaughter. Virginiamycin (VM) has been used to prevent sub-acute ruminal acidosis (SARA) and subsequently control liver abscess incidence. This study observed the interrelationship between VM inclusion (240 mg/hd/d), ruminal pH dynamics, and hepatic blood metabolites over a 150-d feeding trial. Housed in a Calan gate system, 120 Angus crossbred steers (291 ± 28 kg) were randomly assigned to 1 of 6 dietary treatments: no VM (T000); VM for the last 50 d (T001); VM for the last 100 d (T011); VM for the first 50 d (T100); VM for the first 100 d (T110); and VM for 150 d (T111). Steers were orally administered 2 indwelling smaXtec rumen pH and temperature recording boluses on d -4 and d 84. On d -7, 28, 56, 84, 112 and 140, blood samples were collected via jugular venipuncture and all plasma samples were analyzed for concentrations of albumin, alkaline phosphatase, direct bilirubin, total bilirubin, gamma-glutamyl transferase, and total protein using an automated blood analyzer (Carysta High Volume Chemistry Analyzer; Zoetis). Haptoglobin (HPT) was measured following a colorimetric method based on peroxidase activity. Data were analyzed using a random coefficients model with the pen as a random effect and animals within treatment as the subject. Results indicated that VM did not convalesce hepatic function (P > 0.05), but HPT had increased concentrations on d 84 for VM excluded treatments (42.75 vs. 93.25 mg/L). Comparatively, T111 tended to have less time under pH 5.8 (2.50 h/d) when compared with T001, T100, and T000 (5.27; 4.94; and 4.23 h/d, respectively; P = 0.107). Therefore, VM should be fed from the growing phase to slaughter to capture the full potential of the product on animal health status.
Databáze: OpenAIRE
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