PSVIII-15 - Effect of Endovac-Beef vaccination on performance, dietary energetics, and carcass characteristics of growing-finishing calf-fed Holstein steers

Objectives were to evaluate the influence of ENDOVAC-Beef^® (Endovac Animal Health, Columbia, MO) vaccination on calf-fed Holstein steer growth performance, dietary energetics, and carcass characteristics. Fifty Holstein steer calves were utilized in a 322 d trial. Calves were blocked by initial shrunk body weight (134 ±5 kg) and randomly assigned to treatments within weight groups to 10 pens (5 steers per pen, 5 pens per treatment). Five pen groups received the ENDOVAC-Beef vaccination on d 28 and d 56, and the remaining 5 pens did not receive the ENDOVAC-Beef vaccination. All steers were fed the same steam-flaked corn-based growing-finishing diet. Vaccination did not affect (P ≥ 0.10) live weight, average daily gain, and dry matter intake during the 322 d feeding period. However, vaccination increased (P ≤ 0.04) gain efficiency and estimated dietary net energy values (NE) during the first 112 d on feed. Vaccination did not affect (P ≥ 0.14) gain efficiency or estimated dietary NE during the final 112 to 322 d, or over the entire feeding period (1 to 322 d). Vaccination did not affect (P ≥ 0.31) hot carcass weight, dressing percentage, and marbling score. However, vaccinating calf-fed Holstein steers with ENDOVAC-Beef increased (P ≤ 0.01) longissimus muscle area (LMA; 86.5 vs 76.8 cm²) and retail yield (51.3 vs 50.4); but, tended to increase (P = 0.07) carcass fat thickness. Morbidity and pink eye infection were low and not affect by treatment (P ≥ 0.18). We conclude that while vaccinating calf-fed Holstein steers with ENDOVAC-Beef did not have an overall effect on growth-performance, it increased (13%) LMA and retail carcass yield (1.8%).