Variation in Rectal Temperature, Respiration Rate, and Pulse Rate of Cattle as Related to Variation in Four Environmental Variables

Abstract

To determine the relative importance of variations in air temperature, wind velocity, solar radiation, and vapor pressure in producing responses of cattle, a series of four 24-hr. studies in 1953 and five in 1954 were conducted with Brahman, Jersey-Brahman crossbred, Jersey, and "Holstein females. Thirteen observations each of the rectal temperature, pulse rate, and respiration rate of each animal were recorded during the 24-hr. period, i.e., at the beginning of the test period and at intervals of 2 hr. Continuous records of solar radiation, air temperature, vapor pressure, and wind velocity were obtained. Though the primary object was not a breed comparison, the data conform to the findings of previous studies with respect to the relative heat tolerance of the groups studied, the order of heat tolerance being Brahman, most heat-tolerant, followed by 1/~ Jersey_l/2 Brahman, 3~ Jersey_l/~ Brahman, Jersey, and Holstein.