Abstract
From April 1980 to March 1983, 69 farms in Chiba prefecture were studied on a correlation between incidence rates of bovine diseases and climatologic factors. From the socio-demographic and management with diseases were drawn out by the method of Quantitative Model III. Correlations between the important factors and the incidence rates were analysed by the method of Quantitative Model I. The results obtained are as follow.
1. There was generally a positive correlation between the monthly incidence rates of “All-disease” and “mastitis”, and the mean monthly temperature and humidity (p<0.05) . The incidence rates of “reproductive disorder” and “infertility”, however, were not associated with such climatic factors. These results suggested that effect of climatic factors such as temperature and humidity depended on the diseases.
2. A correlation between the incidence rate of “all-disease” and environmental factors was analysed by the method of Quantitative Model I. The results showed that the incidence rates of “all-disease” tend to be higher at large scale farms run by young full-time managers intending to increase milk production.
3. The incidence rates of “reproductive disorder” were more strongly associated with managemetal factors, especially with the age of manager and the presence of successor than were that of the other diseases. It tended to be low at farms managed by older men having longer experience.
4. The incidence rates of “infertility” were associated with the factors concerned with management, burn-environments and burn-structures and tended to be higher at the farms having bad burn-environments. It seemed to be higher at the farms managed by young men eager to have a higher boost of milk production.
5. The incidence rates of “mastitis” were associated with the factors concerned with burnenvironments and -structures especially with ditch and feeding structures. It tended to be high at the large scale farms managed by the men attempting to increase milk production.
