Reducing and Refining Antimicrobial Drugs Use for Diarrhea in Calves

Diarrhea is the most important calf disease during the first month of life and a main reason for antimicrobial drug use on farms. Regardless the cause of diarrhea, antimicrobial drugs is recommended as part of medical management of diarrheic calves. The main rational for antimicrobial drug administration to diarrheic calves is to prevent or treat bacteremia and limit the overgrowth of Escherichia coli in the gastrointestinal tract. Bacteremia occurs in approximately 30% of diarrheic calves regardless of the inciting cause with E coli being isolated from 50% of the blood cultures. Therefore, some authors recommend the use of antimicrobial drugs for treatment of diarrheic calves with signs of bacteremia or sepsis. However, evidence-based guidelines regarding whether antimicrobial drugs are necessary for treatment of calf diarrhea are limited. In fact, the practice of administering antimicrobials drugs to diarrheic calves is more common than medically justified. Approaches to decrease antimicrobial drug use in diarrheic calves have recently been studied focusing on 3 main general areas: disease prevention, reduction of the total mass of antimicrobial drug usage and improvement of stewardship (refining antimicrobial drug usage). The objectives of this presentation are to critically review studies related to antimicrobial drugs usage in diarrheic calves to determine the impact of different interventions in reducing and refining antimicrobial drug usage and their effect on calf morbidity and mortality.