Avaliação das possíveis reações adversas causadas pela aplicação da vacina bivalente contra febre aftosa em bovinos leiteiros e de corte

Abstract

Foot-and-mouth disease is an acute, highly contagious disease with significant potential for transmissibility and morbidity, which have an impact on production and restrictions on international trade in live animals and by-products. In Brazil, the general guidelines for its prevention include, among other actions, systematic and compulsory vaccination against footand- mouth disease in cattle and buffalo in free zones with vaccination. However, the use of the FMD vaccine can cause reactions such as abscesses at the site of application, which may be related to incorrect administration, contamination at the time of vaccination, and the oily adjuvant in the vaccine itself. In this context, the aim of this study was to evaluate the possible adverse reactions caused by the application of the bivalent foot-and-mouth vaccine in beef and dairy cattle. To this end, a study was carried out with 98 cattle vaccinated against foot-andmouth disease, 48 of which were dairy cattle aged between 3 and 11 years, all females in the production phase. And 50 beef cattle aged between 18 and 22 months, of which 23 were males and 27 females, with no previous lesions on the neck board. The presence of adverse reactions was observed on day zero before vaccination, 15, 30 and 45 days after vaccination. The evaluation was carried out through direct observation and palpation and, in cases where there was a local vaccine reaction, the nodule was measured using a caliper and/or tape measure. The data obtained from the observations before, during and after vaccination were processed, followed by analysis and interpretation using Pearson's chi-squared test. Of all the cattle evaluated, 20.41 % (20/98) developed a vaccine reaction, characterized by the presence of a nodule at the vaccine application site. In view of the changes observed, there was a significant difference (p>0.05) between the dairy (33%) and beef (8%) animals evaluated in terms of the frequency of nodule formation. It was also observed that 56.25% (9/16) of the dairy animals with abscesses were around 10 years old. And the animals that had abscesses in the first evaluation kept them in the others. No weight loss was observed in the cattle during the evaluation period because of possible vaccine reactions. It can therefore be concluded that even with the new bivalent vaccine against foot-and-mouth disease, a local vaccine reaction with nodule formation was observed, but less frequently in the herd