| This is an investigation of Salmonella prevalence on Ontario swine farms using liquid or dry feeding. Salmonella spp were cultured from at least one sample from 11 of the 41 farms (27%). Eight farms (38%) using dry feed tested positive compared to only three liquid feeding farms (15%). In the final logistic regression model, with farm as random effect, liquid feeding and all-in/all-out flow system were associated with a decreased Salmonella infection status. S. Typhimurium was isolated from four farms in the dry-feed group and one farm with liquid feeding. The one S. Typhimurium isolate from the liquid feeding farm exhibited no antimicrobial resistance, but those from dry-feeding farms were resistant to four or more antimicrobial agents. In the multi-variable linear regression model, with farm as random effect, dry feeding was associated with a higher Salmonella antibody titre. The ELISA tests and culture demonstrated disagreement at the pig level but at the herd-level, exhibited a fair agreement (kappa = 0.3). There was no agreement between the two ELISA tests (Salmotype and IDEXX) at the pig level. At the herd-level, on the other hand, a very good agreement (kappa = 0.84) was observed between the two ELISA tests. |
