Some aspects of oestrus in cattle, with reference to fertility on artificial insemination. 3. Body temperature and the oestrus cycle

Abstract

Two groups, each of 10 Jersey cows, were observed for periods of 99 and 86 days, respectively, in succeeding years. Mean body temperature was 100.2±0.8°F (n=1,824) in the morning and 101.4±0.8°F. (n=1,764) in the evening. Eighteen oestrous periods were detected in the morning; 13 were noted in the evening; and in 6 cases oestrus was evident at morning and evening. No correlation could be established between stages of the oestrous cycle and morning or evening temperature trends, except that a thermogenic response (P<0.001) in the presence of oestrus was noted. Preliminary investigations indicate that the response persists for the duration of oestrus. It is suggested that the use of the temperature rise at oestrus could be an adjunct to more conventional methods of oestrus detection if exercised with care and judgment. The significance of the thermogenic response at oestrus in relation to metabolic processes is considered, and attention is drawn to its possible importance in heat regulation and in adaptation to unfavourable environments.