An evidence-based algorithm for parenteral antimicrobial treatment of neonatal calf diarrhea-A blinded randomized...

Neonatal calf diarrhea (NCD) is a common and economically important condition, often leading to use of antimicrobial drugs (AMD) despite limited evidence to guide treatment decisions. The objective of this blinded, non-inferiority randomized controlled trial was to assess the effectiveness of an evidence-based algorithm (EBA) for AMD therapy of NCD. A total of 106 calves from a calf-raising facility were enrolled. The study compared 2 treatments. (1) An EBA, in which calves received an AMD only if they exhibited 2 or more of the following clinical signs: rectal temperature >38.8°C after anti-inflammatory medication, inability to stand, absent suckle reflex, sunken eyes, or scleral injection; or (2) a control group (CG), in which all calves received an AMD (trimethoprim-sulfadoxine 16 mg/kg) at the onset of diarrhea. Survival analysis, linear and logistic regressions, and negative binomial models were used to assess diarrhea duration, mortality, weight gain, treatment for respiratory disease, and number of days with clinical signs of respiratory disease. In the EBA group, 40% (21/52) of the calves received AMD treatment. Diarrhea duration did not differ between groups; the median duration was 4 d (interquartile range [IQR]: 2-7 d) in the EBA group and 3 d (IQR: 1.5-8.5 d) in the CG. Control calves were more likely to require more rescue therapy (odds ratio: 6.3; 95% CI: 1.3-62.1) and had signs of pneumonia for longer (CG vs. EBA incidence rate ratio: 9.1; 95% CI: 1.4-58.7) than EBA calves. The results are supportive of targeted use of AMD, providing outcomes comparable to, and potentially better than, blanket AMD use for diarrhea.