Table 2. Period summary (2013–2015) of antimicrobial use via feed in broiler chicken flocks, frequency, reasons for use and seasonal variations.
| 2013 | 2014 | 2015¥ | Total | Reasons for use, period total | Seasonal variations § | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| n = 97 | n = 141 | n = 135 | n (%) | Treatment | Prevention | GP | Diseases targeted | Summer | Fall | Winter | ||
| Antimicrobials | ||||||||||||
| II | Penicillin G potassium | 0 | 5 | 5 | 10 (3%) | 0% | 2% | 0% | Necrotic enteritis | 5% | 3% | 0% |
| Penicillin G procaine | 12 | 12 | 13 | 37 (10%) | 1% | 9% | 1% | Necrotic enteritis | 3% | 12%↑ | 10% | |
| Trimethoprim-sulfadiazine | 15 | 17 | 15 | 47 (13%) | 12% | 0% | 0% | Neonatal diseases, airsacculitis | 10% | 14% | 10% | |
| II | Tylosin | 7 | 28 | 20 | 55 (15%) | 0% | 15% | 0% | Necrotic enteritis | 16% | 10% | 35%↑ |
| Virginiamycin | 45 | 28 | 22↓ | 95 (25%) | 0% | 23% | 2% | Necrotic enteritis | 29% | 23% | 29% | |
| III | Bacitracin | 47 | 82 | 69 | 198 (53%) | 0% | 49% | 3% | Necrotic enteritis | 56% | 53% | 50% |
| Oxytetracycline | 1 | 1 | 2 | 4 (1%) | 1% | 0% | 0% | Necrotic enteritis | 0% | 2% | 0% | |
| IV | Bambermycin | 1 | 0 | 7 | 8 (2%) | 0% | 0% | 2% | n/a | 0% | 3% | 0% |
| N/A | Avilamycin | 0 | 33 | 46↑ | 79 (21%) | 0% | 21% | 0% | Necrotic enteritis | 8% | 29%↑ | 6% |
| Ionophores | ||||||||||||
| IV | Lasalocid | 10 | 4 | 1 | 15 (4%) | 0% | 4% | 0% | Coccidiosis | 6% | 4% | 0% |
| Maduramicin | 0 | 10 | 1 | 11 (3%) | 0% | 3% | 0% | Coccidiosis | 9% | 1%↓ | 0% | |
| Monensin | 28 | 45 | 39 | 112 (30%) | 0% | 30% | 0% | Coccidiosis | 23% | 25% | 69%↑ | |
| Narasin | 21 | 31 | 22 | 74 (20%) | 0% | 20% | 0% | Coccidiosis | 22% | 18% | 25% | |
| Narasin-nicarbazin | 30 | 37 | 47 | 114 (31%) | 0% | 31% | 0% | Coccidiosis | 27% | 34% | 21% | |
| Salinomycin | 35 | 50 | 56 | 141 (38%) | 0% | 29% | 0% | Coccidiosis | 43% | 41% | 13%↓ | |
| Chemical coccidiostats | ||||||||||||
| N/A | Nicarbazin | 34 | 40 | 47 | 121 (32%) | 0% | 32% | 0% | Coccidiosis | 24% | 33% | 46%↑ |
| Decoquinate | 0 | 24 | 4 | 28 (8%) | 0% | 8% | 0% | Coccidiosis | 16% | 5%↓ | 4% | |
| Clopidol | 11 | 7 | 8 | 26 (7%) | 0% | 7% | 0% | Coccidiosis | 5% | 8% | 4% | |
| Diclazuril | 7 | 0 | 2 | 9 (2%) | 0% | 2% | 0% | Coccidiosis | 5% | 2% | 0% | |
| Zoalene | 3 | 3 | 3 | 9 (2%) | 0% | 2% | 0% | Coccidiosis | 3% | 2% | 2% | |
| Robenidine | 0 | 1 | 3 | 4 (1%) | 0% | 1% | 0% | Coccidiosis | 1% | 1% | 0% | |
| No medication in feed | 7 | 13 | 14 | 34 (9%) | 8% | 10% | 6% | |||||
Roman numerals II to IV indicates categories if importance to human medicine as outlined by the Veterinary Drugs Directorate, Health Canada. N/A-not applicable; no VDD classification at the time of writing of this manuscript. GP–Growth promotion.
¥ For the temporal analysis, 2015 was compared to 2013 (initial surveillance year) and 2014 (previous year). Bold fonts represent significant temporal differences (P≤0.05) and the arrows (↓ or ↑) represent downward or upward directionality of the change.
§ For the seasonal variations, summer (grown between May and August) was compared to winter (grown between January to April) and fall (grown between September to December). Bold fonts represent significant seasonal differences (P≤0.05) and arrows (↓ or ↑) represent downward or upward directionality of the change.