Abstract
This study aimed to assess the impact of foot-and-mouth disease (FMD) vaccination on milk production in dairy cows. In Experiment 1, 593 lactating Holstein cows (37.2 ± 0.3 kg/day), housed in a free-stall system, were randomly assigned to receive (n = 268) or not receive (n = 325) a dose of the FMD vaccine on Day 0 of the experiment. Milk yield was recorded from Day -3 to Day 9, and body temperature was measured from Day 0 to Day 3. Among cows producing ≥ 37.2 kg/day, vaccinated animals had a significantly lower milk yield than unvaccinated controls from Days 1 to 5 post-vaccination (40.7 ± 0.3 kg/day vs. 42.9 ± 0.3 kg/day; P vs. 32.9 ± 0.3 kg/d; P n = 96), vaccinated cows had higher body temperature on Day 1 (39.1 ± 0.1 °C vs. 38.2 ± 0.1 °C; P n = 78) or not receive (n = 68) a dose of the FMD vaccine on Day 0. Milk yield was measured on Days 0 and 3, and milk composition, somatic cell count, and milk urea nitrogen were analyzed on Day 3. No significant differences were observed between experimental groups for any of these variables. In conclusion, FMD vaccination caused only a transient milk yield reduction in high-producing cows (∼40 kg/day, free-stall system), but no significant effect was seen in lower-producing cows (∼20 kg/day, pasture-based system).