Adverse reactions to bivalent vaccine against foot-and-mouth disease in beef and dairy cattle.

This study aimed to evaluate adverse reactions to the bivalent foot-and-mouth disease (FMD) vaccine in beef and dairy cattle. A non-probabilistic intentional sample of 98 animals was evaluated: 48 dairy cattle (3-11 years old) and 50 beef cattle (18-22 months old; 23 males and 27 females), all clinically healthy and without previous cervical lesions. Observations were performed on days 0 (pre-vaccination), 15, 30, and 45 post-vaccination, through clinical inspection and palpation, with measurement of nodules, when present, using a caliper and/or measuring tape. Data were analyzed using Pearson's Chi-square test (p<0.05). Local vaccine reactions were recorded in 20.4% (20/98) of animals, occurring significantly more often in dairy cattle (33%) than in beef cattle (8%). Among dairy cattle, 56.3% (9/16) of those with abscesses were approximately 10 years old. Animals that developed lesions at the first evaluation maintained them throughout the study period. No weight loss was associated with vaccine reactions. In conclusion, although the bivalent formulation reduces adverse effects, abscess formation may still occur, highlighting the need for monitoring and the adoption of good vaccination practices.