Shorn and unshorn Awassi sheep II. Pulse rate

Abstract

1. A comparison was made between the pulse rate of shorn and unshorn sheep maintained in the shade and direct sunlight during the various seasons of the year.2. The variability of the pulse rate during the day generally agreed with the daily changes in body temperature and presumed level of metabolism. Fluctuations were greater in unshorn sheep.3. Pulse rate was lower during summer (60–100 for unshorn and 63–100 for shorn sheep) than in winter (90–130 for unshorn and 90–115 for shorn sheep). It tended to increase with a rise in ambient temperature, especially during winter and spring. A lower pulse rate accompanied a rise in environmental temperature, during summer. The slowest pulse rate of 42 per minute was observed during summer in the hot dry area.4. The pulse rate of both groups increased with a rise in rectal temperature, particularly at low ambient temperatures. At comparable rectal temperatures, a higher average pulse rate was observed in shorn sheep during winter and spring. With elevated summer temperatures, equal pulse rates were noted in both groups of equal rectal temperatures. Since the rectal temperatures of the shorn exceeded that of unshorn sheep, in high environmental temperatures, and in the sun, their pulse rate under these conditions was also higher.5. The differences in pulse rate between the two groups appeared to reflect the combined effects of metabolic rate, body temperature and the vasomotor activity, all of which vary with season and environmental temperatures.