Abstract
Summary Effects of the subtropical climate of central Texas on the heat-regulatory ability of dairy heifers were studied in 1955 and 1956. Physiological responses of the heifers—body temperature, pulse rate, and respiration rate—to environmental effects—air temperature, solar radiation, vapor pressure, and wind velocity—were studied. The effects of solar radiation were of primary interest. Solar radiation had a direct effect on body temperature when air temperatures where close to the range of thermo-neutrality (below 90° F.). In higher air temperatures (above 90° F.), solar radiation had little effect on the changes in body temperatures. Respiration rate, the most consistent physiological response studied, was affected more by solar radiation than by the other weather influences. Large differences in respiration rate due to genetic origin were also observed. It could not be demonstrated satisfactorily that pulse rates were influenced by any of the environmental variables. Body temperature data and respiration rate data taken on animals in the absence of direct solar radiation were almost as reliable indicators of differences in heat regulatory ability as the same measurements taken on animals in the presence of direct solar radiation.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
