Management of calves in commercial dairy farms in Mecklenburg-Western Pomerania, Germany and its impact on calf mortality and prevalence of rotavirus and Cryptosporidium parvum infections in pre-weaned calves

In a cross-sectional study, impact of management in dairy farms on calf mortality rates and prevalence of rotavirus and Cryptosporidium parvum in feces of calves was investigated. Sixty-two commercial dairy herds in Mecklenburg-Western Pomerania, Germany, were stratified selected in 2019. We performed in-person interviews and fecal specimens in samples of all-female calves of age 7 up to 21 days. Management data were documented on farm level. A Multiscreen Ag-ELISA was performed to determine rotavirus and Cryptosporidium parvum. Associations between two calf mortality rates, detection of C. parvum and rotavirus, and predictors were examined with GLM models. In farms with routine vaccination against respiratory diseases, 31-days mortality rate was 4.2% +/-1.26 compared to 7.6% +/-0.97 (p = 0.040) on non-vaccinating farms. Six-months mortality was lower in farms that continued feeding milk to calves during periods of diarrhea compared to farms that did not (6.9% +/-0.8 vs. 12.4% +/-2.3). In case of a routine shifting of calves from the calving box into calf boxes less C. parvum was detected compared to an individual moving of calves (33.3% +/-2.6 vs. 19.6% +/-5.3; p = 0.024). Our model confirms a positive association between occurrence of aqueous feces and frequency of detection of C. parvum (45.4% +/-23.6 vs. 21.4% +/-18.7; p < 0.001). Frequency of detection of rotavirus was lower in farms that reported a defined amount of applicated colostrum per calf than in farms that presented a range of colostrum instead of a defined amount. This study indicates the potential for mitigation of risk factors for mortality in calves.