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

Monday, June 27, 2022

9:30 AM – 9:45 AM CT

Location: Oklahoma City Convention Center, 301 C/D

Presenting Author(s)

Luiz Fernando Dias Batista

Graduate Student
Texas A&M University
College Station, Texas

Author(s)

Madeline E. Rivera

Graduate Student
Texas A&M University
College Station, Texas
Luis O. Tedeschi, PhD

Professor
Department of Animal Science/Texas A&M University
College Station, Texas

Abstract:
Virginiamycin (VM) is an antibiotic that possesses antimicrobial properties due to its ability to block protein synthase in Gram-positive bacteria. It reduces lactic acidosis and the incidence of liver abscesses. Animal growth and development is brought about because of improved ruminal health, and animal health and welfare. This study evaluated the continuous or intermittent provision of VM during the growing and finishing phases on 120 Angus-crossbred steers (291 ± 28 kg) in 20 pens equipped with a Calan gate feed system from which animals received VM (240 mg/d) as follow: no VM (T₀₀₀); VM in the last 50 d (T₀₀₁); VM for the last 100 d (T₀₁₁); VM in the first 50 d (T₁₀₀); VM in the first 100 d (T₁₁₀); and VM for 150 d (T₁₁₁). Data were analyzed using a random coefficients model with the pen as a random effect and animals within treatment as the subject. The T₀₁₁tended (0.075 ≥ P ≥ 0.052) to have a greater carcass, final shrunk body weight compared with T₁₁₀. Empty body fat (EBF; %) tended (0.080 ≤ P ≤ 0.050) to be less for animals that consumed VM regardless of the period or length of feeding. Dry matter intake (DMI) was lesser for T₁₁₁compared with T₀₀₀, and greater for T₀₁₁compared with T₁₁₀(P ≤ 0.028), which resulted in greater average daily gain (ADG) with no difference in feed efficiency (P = 0.015 and 0.225, respectively). ADG-adjusted metabolizable energy (aME) content increased by 3.08% for T₁₁₁compared with T₀₀₀. This study indicated that daily supplementation of 240 mg VM during the whole feeding phase increased feed efficiency and paME, whereas when withdrawn during the end of the finishing phase (T₁₁₀) can impair DMI and ADG.