CARBADOX AND SULFAMETHAZINE AS GROWTH PROMOTERS IN TWO SWINE HERDS WITH ATROPHIC RHINITIS

Abstract

Two trials were conducted with recently weaned 9-kg pigs fed to 95 kg, when naturally affected with atrophic rhinitis, to determine the effect of feeding carbadox and sulfamethazine, alone or in combinaton, up to 35 kg liveweight, on the performance of pigs fed to 95 kg. Trial locations, using similar management practices, were selected in Ontario and Saskatchewan based on a previous history of chronic atrophic rhinitis. In the starter period, carbadox fed alone or in combination with sulfamethazine, improved (P < 0.05) average daily gain (ADG) as compared to non-medicated controls. A combined evaluation of the data also revealed that the former treatments also enhanced (P < 0.05) feed efficiency (FE), whereas sulfamethazine alone had no impact (P > 0.05) upon performance in the starter period. Following drug withdrawal up to market, performance differences (P < 0.05) were not observed between treatments. However, sulfamethazine alone tended to increase (P > 0.05) ADG as compared to the other treatments, while the other medicated treatments tended to improve (P > 0.05) FE. When starter and grower periods were combined, significant (P < 0.05) performance improvements were not apparent, although each medicated treatment increased (5–7%) ADG. Carbadox and carbadox/sulfamethazine tended to improve feed efficiency more than sulfamethazine alone. While the combination treatment produced some improvement (P > 0.05) in feed efficiency as compared to carbadox alone, this was not considered to be additive. Use of the medications did not result in a reduction of mean nasal lesion score due to atrophic rhinitis. Key words: Carbadox, sulfamethazine, atrophic rhinitis, pigs