Mortality, Morbidity, Case-fatality, and Culling Rates for California Dairy Cattle as Evaluated by the National Animal Health Monitoring

Gardner, I.A., Hird, D.W., Utterback, W.W., Danaye-Elmi, C., Heron, B.R., Christiansen, K.H. and Sischo, W.M., 1990. Mortality, morbidity, case-fatality, and culling rates for California dairy cattle as evaluated by the National Animal Health Monitoring System, 1986-1987. Prey. Vet. Med., 8: 157-170. During 1986 and 1987, mortality, morbidity, case-fatality, and culling rates were estimated for endemic disease conditions in 43 randomly selected California dairy farms. Data were collected mainly by farmer interview. Age-specific mortality rates were: calves 22.8 per 1000 calf-months at risk; young stock 1.2 and cows 2.0 per 100 animal-years at risk. No bulls died during the observational period. For calves, diarrhea/enteritis and pneumonia had the highest incidence rates, 115.8 and 76.5 per 1000 calfmonths at risk, respectively. Average incidence rates per 100 cow-years for the five most commonly reported cow diseases were: mastitis 30.3; infertility 7.9; metritis 7.0; footrot 5.5; retained placenta 4.7. The highest case-fatality rate was 32% for cows with traumatic reticulitis (hardware disease ). About 25% of all cows were culled. Low production, infertility, and mastitis accounted for 87.6% of all culled cows. Characteristics of participating herds and diagnostic criteria are presented. Limitations of the data and of the collection methods are discussed.