ANTIMICROBIAL DRUG-USE AND RELATED MANAGEMENT-PRACTICES AMONG ONTARIOSWINE PRODUCERS

A mail survey of swine producers in Ontario was undertaken during 1991 to describe the types, frequency, and motives for antimicrobial use. Two hundred operations that marketed fewer than 350 hogs per year, and 800 that marketed more than 350 per year were sent questionnaires, 63 % of which were completed and returned. Most operations (86%) added an timicrobials to starter (weanling pig) rations, while fewer (29%) adde d these drugs to finisher pig rations. The most commonly used antimicr obials were tylosin, carbadox, and furazolidone in weanling pigs, and tylosin, lincomycin, 80% of farms had injected at least some grower-fi nisher pigs with antimicrobials in the 12 mo preceding the survey. App roximately 20% of operations that added antimicrobials to finisher rat ions did so for growth promotion purposes only, while others used them for disease treatment, prevention, control, or a combination of reaso ns. Among those not using antimicrobials in finisher rations, 83% did not believe they were necessary and 37% were concerned about the poten tial for residues in marketed hogs.