Antimicrobial drug use and clinical health score of udder-reared dairy calves on Swiss organic farms

Summary

During the recent decade, cow-calf rearing systems, which allow calves to suckle milk from a dairy cow for parts or all of the rearing period are increasingly gaining public interest. To date, no epidemiological multi-herd study exists that evaluates calf health and antimicrobial use for dairy farms using cow-calf rearing systems. This study quantified incidence densities (ID) of veterinary treatment events, antimicrobial treatment incidences (TI) and clinical health scores for dairy calves reared with udder access on 14 organic dairy farms in Switzerland and Southern Germany. Antibacterial drugs were used on 31% of farms and antiparasitic drugs on 15% of farms. Overall, a median ID of 25.35 veterinary treatments per 100 calf-years, a maximum TIUDD of 40 antimicrobial daily doses and a median calf mortality risk of 3% were found. Assessments of the calves’ health using clinical health scores, revealed nasal discharge (23.5%) to be the most frequent health impairment, followed by ocular discharge (22.9%) and skin conditions (19.7%). Perianal soiling was observed in 10.1% of calves. Five percent of calves qualified as severely health impaired. Compared to conventional Swiss dairy farmers who rear calves artificially, antimicrobial drug use was substantially lower. This can partly be attributed to the mind-set of organic farmers. In severe cases of calf disease, organic farmers should not be reluctant to resort to antimicrobial drugs, such as to prevent avoidable calf suffering and mortality.