Table IV.

Rate of injectable antimicrobial use by mean kg of active ingredient/1000 animal-days (audit data) n = 21 farms

Category of importance to human medicinea	Antimicrobial	Mean kg of active ingredient disposed per 1000 animal-daysb	95% Confidence interval
I	Ampicillin-sulbactam	0.04 × 10−3	0.00 × 10−3 to 1.45 × 10−3
	Ceftiofur	0.02 × 10−3	0.00 × 10−3 to 3.78 × 10−3
	Enrofloxacinc	0.00 × 10−3	0.00 × 10−3 to 2999281383
II	Aminoglycosidesd	0.01 × 10−3	0.00 × 10−3 to 75.84 × 10−3
	Macrolides	0.54 × 10−3	0.21 × 10−3 to 1.39 × 10−3
	Penicillin	0.59 × 10−3	0.24 × 10−3 to 1.46 × 10−3
	Trimethoprim-sulfadoxinee	0.13 × 10−3	0.02 × 10−3 to 0.90 × 10−3
III	Florfenicol	0.53 × 10−3	0.20 × 10−3 to 1.38 × 10−3
	Oxytetracycline	2.37 × 10−3	1.51 × 10−3 to 3.73 × 10−3
	Spectinomycin	0.18 × 10−3	0.03 × 10−3 to 0.93 × 10−3
Unclassified	Tiamulinc,f	0.01 × 10−3	0.00 × 10−3 to 11.04 × 10−3

^aRanking of importance to human medicine (15).

^bThe mean rates were significantly different between tetracycline and the following drugs: ampicillin-sulbactam, florfenicol, macrolides, penicillin, spectinomycin, and trimethoprim-sulfadoxine (pair-wise comparisons all P < 0.05). All other pair-wise comparisons of rates were not significantly different (P > 0.05).

^cNot labelled for cattle use at the time of the study.

^dIncludes gentamicin and dihydrostreptomycin.

^eCombination products were placed in a category higher than their constituents as per CIPARS 2002 (8).

^fTiamulin (a pleuromutilin) is not currently listed in Health Canada’s current categorization system.