Intestinal spirochaetal infections in pigs following transportation to growing facilities is predisposed by stressful factors such as contact between carriers and non-immune piglets, defficient environment and diet changes. To neutralize such effects, it is a common practice to include antimicrobials to feed in promoting or control levels. The present work assessed the occurrence of Brachyspira infection in pig herds in the State of Rio Grande do Sul, Brazil, trying to relate the infection with the feed medication program. A total of 393 rectal swabs collected from 38 farms were bacteriologically examined (22 from farms using medicated feed and 16 with non-medicated feed). B. hyodysenteriae and B. pilosicoli were isolated respectively from 0% and 6,25% in medicated herds and from 31.8% and 45.5% in non-medicated farms. B. hyodysenteriae and B. pilosicoli were isolated respectively from 0% and 0.6% swabs collected in medicated farms and from 3.9% and 7.3% swabs from non-medicated farms. The present work agrees with several authors who suggest a direct influence of inclusion of antimicrobials to feed in promotion on growth levels on spirochaetal diarrhoea in pigs. However, considering the multifactorial determination of this condition, additional studies investigating the importance of other variables would be necessary to reach a definitive conclusion about the role of medication in the determination of diarrhoea caused by pathogenic spirochetes.
Swine Dysentery; Spirochetal Colitis; Brachyspira; growth promoters; antimicrobials; feed medication
