Antimicrobial use and decision making with respect to treatment of diarrhea in Canadian dairy calves.
Antimicrobial resistance in livestock is a growing concern due to possible transmission to humans so it is important to understand antimicrobial use in farm animals. Dairy calves may receive antimicrobials for the treatment of diarrhea, but it is unclear under what circumstances antimicrobials are used. The objective of this study is to investigate antimicrobial use and case-specific information used in treating diarrhea in Canadian dairy calves. A total of 105 dairy farmers (Ontario: 31; Alberta: 28; British Columbia: 26; Nova Scotia: 20) were selected purposively and completed a questionnaire in person about calf health. First, farmers were asked, “Do you use antimicrobials to treat calf diarrhea?” Second, only those who used antimicrobials to treat diarrhea were asked, “What case-specific information do you use to select a diarrhea case for antimicrobial treatment?” Respondents were instructed to select all that apply from a list of 4 symptoms (fecal consistency, fever, attitude, level of dehydration) or otherwise specified. The average herd size was 162 milking cows (range 36–560). Among 105 farmers, 72% used antimicrobials to treat diarrhea. Among those who used antimicrobials for diarrhea, 78% used “fecal consistency,” 61% used “fever,” 55% used “attitude,” 53% used “level of dehydration,” and 28% used 11 other characteristics as indicators to treat diarrhea with antimicrobials. The most common answer was selecting all 4 symptoms given, which was selected by 20% of those who used antimicrobials to treat diarrhea. Among 59 farmers who used fecal consistency as an indicator to treat diarrhea with antimicrobials, only 15% solely used this criterion. Among 91 farmers who were asked whether they had a written treatment protocol for calf diarrhea, 35% reported that they have the protocol and 94% of them were discussed with veterinarians. Treatment decisions could be improved for those who solely depend on fecal consistency as an indicator to treat diarrhea with antimicrobials, as well as developing protocols with a veterinarian, to encourage prudent use of antimicrobials in dairy calves.