A multidisciplinary approach to reduce and refine antimicrobial drugs use for diarrhoea in dairy calves

This study evaluated the impact of a multidisciplinary intervention to reduce and refine antimicrobial drug use for treatment of diarrhoea in dairy calves. The intervention consisted of modification of management practices for disease prevention, health evaluation training of farm staff, implementation of an algorithm directed at antimicrobial therapy for diarrhoeic calves, and monthly farm visits. A combination of retrospective (before intervention period [BP], 1 year) and prospective (immediately after intervention period [AP], 1 year) cohorts were used. Health outcomes measured included incidence of diarrhoea and overall mortality. Antimicrobial treatment rates for diarrhoea and total mass of antimicrobial drugs used at the calf and farm level were also evaluated. Outcomes were assessed using the χ² or Fisher's exact test, and odds ratios and 95% confidence intervals (95% CI) were calculated. Records of 2049 and 2251 calves from 10 farms were available in the BP and AP, respectively. Reduced antimicrobial treatment rates occurred on seven farms (P < 0.01), but not on three farms in the AP. A total of 85% (1303/1573) and 18% (310/1698) of diarrhoeic calves were treated with antimicrobial drugs in the BP and AP (P < 0.001), respectively. There were no differences in the incidence of diarrhoea or mortality between periods. In the AP, the use sulfamethazine and trimethoprim decreased on eight farms, one farm discontinued use of lincomycin and spectinomycin, while two farms discontinued use and one reduced use of cephalosporins. This multidisciplinary approach was effective in reducing antimicrobial drug use for calf diarrhoea on dairy farms without negative impacts on calf health.