The objective was to evaluate the long-term effects of vaccination against endotoxemia on calf-fed Holstein steer growth performance, dietary energetics, and carcass characteristics. Fifty Holstein steer calves were used in a 322 d trial. Calves (134±5 kg) were randomly assigned to treatments within weight groups to 10 pens (5 steers per pen). Five pen groups received an endotoxemia vaccination on d 28 and 56 of the study (EV), and the remaining 5 pens did not receive vaccination. Calves were weighed (off-truck weight, no shrink applied) at start of the study, and on days 122 and 322 (shrunk 4% to account for gut fill). All steers were fed with a steam-flaked corn-based diet. Vaccination did not affect (P≥0.10) live weight, average daily gain, and dry matter intake during the experiment. Although vaccination increased (P=0.04) gain efficiency during the initial 112 d, differences in gain efficiency from d 112 to 322, and during the cumulative feeding period (1 to 322 d) was not appreciable (P≥0.14). Vaccination did not affect (P≥0.31) hot carcass weight, dressing percentage, or marbling score. However, vaccination increased (P<0.01) longissimus muscle area (86.5 vs. 76.8 cm2) and retail yield (51.3 vs. 50.4); but, also tended to increase (P=0.07) carcass fat thick-ness. Morbidity and pink eye rate infection were low and not affected by treatment (P≥0.18). We conclude that whereas vaccinating Holstein calves with EV at days 28 and 56 from arrival did not have an overall effect on growth-performance, it increased (13%) longissimus area and retail carcass yield (1.8%). تفاصيل المقالة