MORTALITY, MORBIDITY, CASE-FATALITY, AND CULLING RATES FOR CALIFORNIA DAIRY-CATTLE AS EVALUATED BY THE NATIONAL ANIMAL HEALTH MONITORING-SYSTEM, 1986-87

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 calf-months 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. © 1990.