|Budget Amount *help
¥2,100,000 (Direct Cost : ¥2,100,000)
Fiscal Year 1995 : ¥500,000 (Direct Cost : ¥500,000)
Fiscal Year 1994 : ¥1,600,000 (Direct Cost : ¥1,600,000)
High temperatures reduce food intake, milk production, and the reproductive performance of cattle grazed on pastures. The regulation of body temperature in high environmental temperatures involves both physiological and behavioral adaptations. Numerous variables about physiological and behavioral aspects should be monitored simultaneously and continuously in order to understand the heat stress. Therefore, a measuring system for polygraphic recording of body temperature, heart rate, respiratory rate, jaw movements, pauses between jaw movements longer than 3 sec, steps and drinking was developed. Grazing and rumination activity, walking distances or jaw movements during summer and autumn were measured in Ibaraki(level land, mild climate)and Yatugatake(high land, cool climate).
In Ibaraki, a daily pattern of grazing and rumination was influenced by the hot summer environments, showing reduced daily grazing and rumination times and significant reduction of the number of jaw movements per min during grazing and rumination. In Yatugatake, on the other hand, a daily pattern of grazing and rumination and grazing times were similar among spring, summer and autum time in summer increased as compared with those in spring and autumn. Behavioral responses of grazing cattle on heat stress was understood. A cause of lower daily gain hot summer was discussed.