Morbidity from nonrespiratory diseases and mortality in dairy heifers during the first three months of life

OBJECTIVE: To describe causes of death, mortality, and morbidity from nonrespiratory diseases in dairy calves. DESIGN: Prospective observational cohort study. ANIMALS: Convenience sample of 410 dairy heifers born between January and December 1990 in 18 south-western New York herds. PROCEDURE: Heifers were examined weekly by a veterinary clinician during the first 3 months of life and all disease conditions were recorded. RESULTS: Crude risks for diarrhea, umbilical infection, and umbilical hernia were 28.8, 14.2, and 15.1%, and the median ages at first diagnoses were 2, 1, and 3 weeks, respectively. Mean durations of umbilical infection and umbilical hernia were 3.7 and 6.7 weeks, respectively. Crude mortality was 5.6%. Case-fatality risks were 12.8% for diarrhea during the first week of life, 5.1% for diarrhea after the first week of life, and 0% for umbilical infection and umbilical hernia. Diarrhea was diagnosed by the caretaker of the clinician; umbilical conditions were diagnosed by the clinician. The primary cause of death was diarrhea in 43%, pneumonia in 24%, septicemia in 10%, and other single causes in the rest of the 21 necropsied calves. CLINICAL IMPLICATIONS: The high incidence and somewhat long duration of umbilical infection, the finding that diarrhea was the primary cause of death, and the high case-fatality risk for diarrhea during the first week of life suggested that calf caretakers need training in the prevention and treatment of these conditions.