Cross-sectional study of antimicrobial use and treatment decision for preweaning Canadian dairy calves

Abstract

Highlights• More than half of producers used multiple signs when treating calf pneumonia.• More than half of producers included systemic signs when treating calf diarrhea.• Farmers with a treatment protocol used multiple signs for antimicrobial use (bovine respiratory disease).• Farmers with a treatment protocol used systemic signs for antimicrobial use (scours).

Recording of calf diseases for potential use in breeding programs: a case study on calf respiratory illness and diarrhea

“…The most common signs used to diagnose diarrhea were, in descending order, alertness, fecal score, and rectal temperature (Table 2). These results are in line with a recent study showing indicators used by Canadian producers when deciding to use antimicrobials (Uyama et al 2022). In particular, for diarrhea treatment, producers considered fecal score (75%), alertness (60%), fever (59%), level of de- hydration (51%), and other signs (24%), while for respiratory disease treatment, producers considered elevated breathing rate (76%), fever (65%), coughing (62%), nasal or ocular discharge (41%), and other signs (27%, which included alertness) (Uyama et al 2022).…”

“…However, this granularity may not be necessary from a genetic point of view because with a standardized phenotype where the outcome is sick or healthy, genetic evaluations may improve calf health regardless of the causative agent (e.g., all forms of respiratory illness or diarrhea are targeted). Clear case definitions may also help increase the amount of data recorded despite potentially reducing the accuracy of the diagnosis (Kelton et al 1998), and the development of common standards to define cases for treatment with antimicrobials have been recommended (Uyama et al 2022). This recommendation also holds true for the recording of calf diseases for breeding purposes, though case definitions may be less stringent than those for prudent antimicrobial usage.…”

“…Most producers reported that they used three indicators (53.9%), followed by all four indicators (38.4%), and two indicators (7.7%) when determining whether a calf has respiratory illness. Uyama et al (2022) similarly reported that over half of the producers used at least three signs to make decisions on antimicrobial usage for respiratory disease in calves.…”

“…Others found that 18% of producers used all diarrhea-specific indicators of fecal score, alertness, level of dehydration, and fever; over 80% used systemic signs (fever, alertness, bloody stool, veterinarian recommendation, no response to previous treatment, etc.) when deciding on antimicrobial treatments for diarrhea (Uyama et al 2022). Recommendations from veterinarians highlight the importance of looking at the disposition and eyes of a calf for early detection of diarrhea as a lack of vigor and sunken eyes are signs of dehydration (Smith 2009).…”

“…The use of multiple indicators for both diseases is the most probable method used by producers to aid in the diagnosis of calf disease events, which can help inform disease treatment (Uyama et al 2022). It should be noted that this describes producer diagnosis of calf diseases as opposed to veterinarian diagnosis.…”