Descriptive epidemiology of fatal abomasal ulcers in Canadian beef calves

Abstract

Retrospective and prospective study designs were used to compile data on 209 cases of fatal abomasal ulceration involving Canadian beef calves < 6 months of age. Retrospective studies of pathology reports and producer records provided data for two of the databases. The third was a prospective study involving necropsy submissions to privately owned veterinary clinics. Data from these three studies were used to describe the age, sex, and breed distribution of calves dying of abomasal ulcers. The monthly distribution of the cases was also described. Most (93.3%) of the fatal ulcers were perforating, the remainder (6.7%) were haemorrhagic ulcers. Calves dying of ulcers ranged in age from 5 days to 6 months, with the average being 45 days. The majority (85.6%) of the cases involved calves < 2 months of age. This age distribution of fatal ulcers closely parallels the timing of forestomach development in naturally reared beef calves, suggesting that ulcerogenesis may be related to forestomach development. The peak number of cases occurred in April and May, suggesting a possible seasonal effect. However, a cohort analysis of calves born in four different months (January, February, March, and April) indicated that season is unlikely to be a factor in fatal ulcer formation. Rather, the clustering of ulcers in April and May likely reflects the underlying age structure of the calf population—most Canadian calves are born in the spring. There was no sex predisposition for ulcer formation, nor was there any conclusive evidence to indicate a breed predilection.