Table 3.
Direction of effect of associations between modifiable non-antimicrobial factors or interventions and antimicrobial resistance in retained citations (n = 39) in animal populations
| Factor or intervention | Species | Increase antimicrobial resistance (no. of associations) | Decrease antimicrobial resistance (no. of associations) | Not statistically associated with antimicrobial resistance (no. of associations) |
|---|---|---|---|---|
| Contact with animals | ||||
| Contact with animals treated with antimicrobials | Pig | 1 | 3 | |
| Diet | ||||
| Addition of egg yolk anti- Salmonella antibody to a ration | Pig | 8 | 7 | |
| Addition of whey to a ration | Pig | 1 | ||
| Ad libitum feeding when compared to restricted feeding | Pig | 1 | ||
| Addition of wet distillers to a ration of steamed flaked corn | Cow | 3 | 1 | 4 |
| A diet associated with a low risk of ruminal acidosis | Cow | 1 | 1 | |
| Addition of S. cerevisisae boulardii to milk replacer | Cow | 1 | 1 | |
| Dietary zinc or copper above NRC recommendation | Cow | 1 | 26 | |
| Health status | ||||
| Unhealthy animals | Cow, pig | 5 | 1 | |
| Routine deworming | Pig | 1 | ||
| Hygiene | ||||
| Dirty pens | Pig | 2 | 1 | |
| Management | ||||
| Non-conventional management systems (e.g. organic, antimicrobial-free, extensive) | Chicken, cow, pig | 2 | 63 | 118 |
| All-in/all-out systems | Pig | 3 | 43 | 6 |
| Increasing pen, group or herd size | Cow, pig | 7 | 61 | |
| Fully slatted floors compared to partially slatted | Pig | 1 | 1 | |
| Heat or cold stress | Pig | 2 | ||
| Education | ||||
| Participation in a quality assurance programme | Cow | 5 | ||
| Non-antimicrobial therapies | ||||
| Treatment with an oral competitive exclusion derived from the intestinal tracts of neonatal pigs | Pig | 3 | 5 | |
| Oral recombinant β-lactamase with parenteral administration of ampicillin | Dog | 3 | 6 | |
NRC, National Research Council Canada.