Emergence of mortality due to centrilobular to massive hepatic necrosis in western Canadian beef calves.

Neonatal beef calves can succumb to several common diseases, including diarrhea and pneumonia, but death associated with hepatic disease is uncommon in this age group. Since 2022, a syndrome characterized by massive hepatic necrosis has been observed in western Canadian neonatal beef calves. This case series describes the clinical presentation, pathology, and ancillary testing done in 22 cases, highlighting the young age (1 to 5 d), varied symptoms observed, and unique liver pathology. Based on the pathology, a toxic cause was suspected, and toxic copper concentrations in kidney tissues were detected in 9/22 cases. Further investigation is required to understand this potentially emerging disease and prevent further occurrences. Key clinical message: Practitioners and pathologists should be aware of a new syndrome of hepatic necrosis in neonatal beef calves when evaluating neonatal calf mortality on western Canadian beef cattle operations. Further study is needed to understand the epidemiology of this condition.