HEALTH-PROBLEMS IN SELECTED ONTARIO HOLSTEIN COWS - FREQUENCY OF OCCURRENCES, TIME TO 1ST DIAGNOSIS AND ASSOCIATIONS

An observational study of 34 Holstein herds from 7 southwestern Ontario counties was undertaken in order to evaluate common clinical diseases. The data consisted of 2204 lactations, and were collected over 2.5 years (October 1980-June 1983). Lactational incidence risks of selected diseases and median time post-partum to first clinical diagnosis were: milk fever 0.056 (0 day), udder oedema 0.060 (1 day), foeta membranes retained 48 h or more 0.077 (2 days), ketosis 0.033 (18 days), vaginitis 0.022 (23 days), metritis 0.107 (26 days), mastitis 0.242 (49 days), teat injuries 0.032 (68 days), foot and leg problems 0.036 (89 days), ovarian cysts 0.050 (90.5 days), and abortions 0.012 (296 days). Results of the present study were consistent with the results of other similar studies. Cows younger than 3 years old were at very low risk of experiencing milk fever. Evidence was found that a potential causal association existed between retained placenta and each of metritis and ovarian cysts, between teat injuries and mastitis, and between milk fever and ketosis.