Shorn and unshorn Awassi sheep IV. Skin temperature and changes in temperature and humidity in the fleece and its surface

1963 ◽  
Vol 60 (2) ◽  
pp. 183-193 ◽  
Author(s):  
E. Eyal
Keyword(s):  
Ambient Temperature ◽  
Skin Temperature ◽  
Vapour Pressure ◽  
The Sun ◽  
Direct Sunlight ◽  
Ambient Temperatures ◽  
Awassi Sheep ◽  
Break Points ◽  
Environmental Temperatures ◽  
Skin Temperatures

1. A comparison was made between the skin temperature, humidity and temperature within and on the surface of the fleece of unshorn and shorn sheep. This study was conducted during various seasons of the year, at different environmental temperatures, while sheep were maintained in the shade or subjected to direct sunlight.2. Accompanying the rise of ambient temperature (in the shade) from 10 to 43° C. there was an increase in skin temperature from 34 to 40° C. and from 28 to 40° C. of the unshorn and shorn sheep, respectively.3. The relationship between the rise in skin temperature and that of ambient temperature was not linear, but showed a stepwise pattern in which the ‘breaks’ occurred at similar environmental temperatures for both groups, although skin temperatures of shorn sheep were lower than the unshorn.4. The diurnal change in skin temperature of the shorn sheep was similar to that of the ambient temperature. The decrease in skin temperature of unshorn sheep sometimes lagged behind the fall in environmental temperature. The seasonal variations between summer and winter were more significant in shorn than in unshorn sheep.5. Fleece surface temperatures measured at the same ambient temperatures ranged between 13 and42° C. and 16·5–39·5° C. in the unshorn and shorn sheep, respectively. In the break points of the rise in skin temperature, there occurred a drop in temperature gradients between the skin and fleece surface. This probably indicates a rise in thermal conductivity of the fleece at these points.6. The temperature gradient per unit of fleece thickness is inversely related to the depth of fleece and is greater the nearer to the skin.7. With exposure to the sun, skin temperatures of both groups greatly increased and occasionally reached 47° C. Under these conditions the differences between shorn and unshorn groups were not consistent.8. Fleece temperatures of unshorn sheep increased greatly upon exposure to the sun. The maximal temperatures were recorded midway between the fleece surface and skin. These temperatures generally reached 55° C. and sometimes even exceeded 60° C.9. At ambient temperatures of 30–35° C. the vapour pressure close to the skin of unshorn sheep ranged between 35–40 mm. Hg. With shorn sheep, however, the vapour pressure close to the skin was similar to that of the environment. In Yotvata there was a rise in vapour pressure close to the skin when the ambient temperature increased to 40–43° C. This rise in humidity was paralleled by a rise of vapour pressure throughout the wool. It was not linear but rather showed a ‘step-wise’ pattern.10. The vapour pressure in fleece and near the skin of sheep subjected to direct sunlight increased considerably (up to 80 mm. Hg). This rise showed a wave-like curve with various degrees of persistency. Appearance of fluid on the skin of Awassi sheep was observed on several occasions.

Shorn and unshorn Awassi sheep III. Respiration rate

1963 ◽  
Vol 60 (2) ◽  
pp. 175-181 ◽  
Author(s):  
E. Eyal
Keyword(s):  
Critical Temperature ◽  
Relative Humidity ◽  
Ambient Temperature ◽  
Respiration Rate ◽  
Rectal Temperature ◽  
The Sun ◽  
Direct Sunlight ◽  
Ambient Temperatures ◽  
Awassi Sheep ◽  
Critical Ambient Temperature

1. Respiration rate of shorn and unshorn sheep was compared; animals were maintained in the shade and in direct sunlight during various seasons of the year, and at different hours of the day. The average respiration rate, for all seasons when sheep were maintained in the shade, was 55 and 32 respirations per minute, for the unshorn and shorn sheep, respectively.The diurnal trend of the respiration rate of shorn sheep resembled that of the ambient temperature. There was a delay in the lowering of respiration rate of the unshorn sheep during the evening hours.2. The critical temperature for the increase in respiration of animals maintained in the shade was 22° C. and 26–30° C. for the unshorn and shorn sheep, respectively.When the animals were exposed to the direct sunlight the critical ambient temperature for the increase in respiration rate was 15–18° C. and 18–22° C. for the unshorn and shorn sheep, respectively. The respiration rate of the shorn sheep exceeded that of the unshorn but decreased very steeply when the animals returned to the shade.3. The effect of humidity was noted particularly with ambient temperatures exceeding 27° C. The respiration rate of the unshorn sheep increased and that of the shorn decreased with the rise in the relative humidity. In the sun there was a rise in the respiration rate of both groups with increase in humidity. The rise was steeper in the shorn animals.4. The effect of the wind in reducing respiration rate was particularly noted on shorn sheep and at elevated ambient temperatures.5. With equal rectal temperature, the respiration rate of shorn sheep was lower than that of the unshorn ones. Assumed critical rectal temperature for the rise in respiration rate was lower in the unshorn sheep.6. The differences between the respiration responses of the unshorn and shorn sheep stemmed from the variation in their thermal balance. The latter resulted from the differences in the insulating characteristics of body surface and the differences between the macroclimate and the microclimate existing in the fleece.

Shorn and unshorn Awassi sheep I. Body temperature

1963 ◽  
Vol 60 (2) ◽  
pp. 159-168 ◽  
Author(s):  
E. Eyal
Keyword(s):  
Body Temperature ◽  
Relative Humidity ◽  
Heat Tolerance ◽  
Environmental Temperature ◽  
The Body ◽  
The Sun ◽  
Direct Sunlight ◽  
Ambient Temperatures ◽  
Awassi Sheep ◽  
Environmental Temperatures

1. The rectal temperatures of shorn and unshorn Awassi sheep were measured at various hours of the day and during various seasons of the year in two different locations in Israel.2. An increase in body temperature accompanied an increase in environmental temperature. A steeper temperature increase was noted in shorn sheep kept in the shade. When ambient temperatures were below 30° C. the body temperature of shorn sheep was lower than that of the unshorn sheep by an average of 0·16° C.3. When ambient temperatures were above 30° C. the body temperature of shorn sheep was equal to or higher than that of unshorn ones.4. Upon exposure to direct sunlight, the body temperature of shorn sheep exceeded that of unshorn animals. However, when the animals were transferred to the shade, or after sunset, the shorn sheep cooled at a faster rate. Their body temperature fell below that of the unshorn sheep during the cool hours of the day.5. Wind velocity, both in the shade and in the sun, had a greater effect on shorn than on unshorn sheep.6. A rise in the relative humidity of ambient temperatures above 25° C. caused body temperature to rise, particularly in unshorn animals. The body temperature of shorn sheep exceeded that of unshorn ones when the animals were maintained in a hot and dry environment.7. While the body of the shorn sheep was entirely affected by the macroclimate, the unshorn sheep were greatly influenced by the microclimate existing in the fleece. Fleece temperatures always lagged behind and were rarely equal to environmental temperatures. Since it was postulated that heat tolerance of certain animals was related to their ability to exploit cool hours of the day, it is suggested that in certain ‘tolerance tests’ records should be taken not only during exposure to heat but also during cool hours of the day.

Extremity skin temperature in British and Zebu cross cattle

1967 ◽  
Vol 69 (1) ◽  
pp. 1-7 ◽  
Author(s):  
K. G. Johnson ◽  
M. E. D. Webster
Keyword(s):  
Skin Temperature ◽  
Lower Leg ◽  
Zebu Cattle ◽  
Temperature Changes ◽  
Ambient Temperatures ◽  
Thermal Environments ◽  
Air Temperatures ◽  
Environmental Temperatures ◽  
Skin Temperatures ◽  
Trunk Skin

1. Extremity skin temperature changes in British and Zebu cross cattle examined in moderate thermal environments followed a thermoregulatory pattern similar to that describedby Whittow (1962). At low environmental temperatures, ear and lower leg skin temperatures were usually only slightly above air temperature. At a variable time after air temperatures began to rise or the animals were fed, extremity skin temperatures increased suddenly to near trunk skin temperature.2. In eight of the ten pairs of animals studied in rising ambient temperatures and during feeding after fasting for 36–72 hr, increases in ear temperature were measured in the British animal before similar changes occurred in its Zebu counterpart. Changes in lower leg skin temperature followed a similar pattern.Trunk skin temperatures and respiratory frequencies were significant higher in British cross animals than in Zebu cross animals of similar thermal history. The mean rectal temperature of both British and Zebu cattle was 38·5 °C.

Shorn and unshorn Awassi sheep II. Pulse rate

1963 ◽  
Vol 60 (2) ◽  
pp. 169-173 ◽  
Author(s):  
E. Eyal
Keyword(s):  
Body Temperature ◽  
Pulse Rate ◽  
Environmental Temperature ◽  
Direct Sunlight ◽  
Ambient Temperatures ◽  
Awassi Sheep ◽  
Summer Temperatures ◽  
Vasomotor Activity ◽  
Environmental Temperatures ◽  
Daily Changes

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.

Effect of ambient temperature on protein breakdown during prolonged exercise

1988 ◽  
Vol 64 (2) ◽  
pp. 550-555 ◽  
Author(s):  
D. G. Dolny ◽  
P. W. Lemon
Keyword(s):  
Ambient Temperature ◽  
Prolonged Exercise ◽  
Respiratory Exchange Ratio ◽  
Protein Breakdown ◽  
Protein Utilization ◽  
Post Exercise ◽  
Ambient Temperatures ◽  
Environmental Temperatures ◽  
Male Subjects ◽  
H Protein

Male subjects (n = 8) cycled for 90 min in 5, 20, and 30 degrees C environments. Rectal (Tre), chest, and thigh temperatures, O2 consumption (VO2), respiratory exchange ratio (R), and venous concentrations of glucose, free fatty acids (FFA), urea N, lactic acid (LA), norepinephrine (NE), epinephrine (E), and cortisol (C) were measured before, during, and after exercise. Urea N excretion was measured in 72 h of nonexercise, in 72 h of exercise (exercise day + 2 post-exercise days) urine samples, and in exercise sweat. Calculated 72-h protein utilization (means +/- SE) was significantly greater (P less than 0.05) for the 5 (86.9 +/- 27.1 g) and 20 (82.9 +/- 22.7 g) compared with 30 degrees C (34.01 +/- 19.1 g) trial. Regardless of ambient temperature exercise increased the venous concentration of C, E, and NE. These catabolic hormones were greatest in 5, lowest in 20, and intermediate in 30 degrees C. Exercise Tre and VO2 were greatest in the 30 degrees C environment. Venous FFA concentration was significantly higher and R significantly lower in 5 vs. 20 or 30 degrees C, and venous LA concentration was significantly greater in 30 vs. 20 or 5 degrees C. Although these results indicate that exercise protein breakdown is affected by ambient temperatures, the mechanism of action is not due solely to circulating NE, E, and C. Differences in venous FFA and LA across environmental temperatures suggest that alterations in carbohydrate and fat metabolism may have contributed to the observed variable protein utilization.

A mechanism by which helium increases metabolism in small mammals

1960 ◽  
Vol 199 (2) ◽  
pp. 243-245 ◽  
Author(s):  
H. A. Leon ◽  
S. F. Cook
Keyword(s):  
Thermal Conductivity ◽  
Oxygen Consumption ◽  
Ambient Temperature ◽  
Skin Temperature ◽  
Heat Loss ◽  
Small Mammals ◽  
Thermal Gradient ◽  
Oxygen Mixture ◽  
Ambient Temperatures ◽  
Long Evans

The oxygen consumption of male Long-Evans rats was determined at three different ambient temperatures in air and in an equivalent helium-oxygen mixture. It was found that when the ambient temperature is near the skin temperature of the rat, the effect of helium is insignificant. If the ambient temperature is lowered, helium induces an increased metabolism over air at the same temperature. Since helium has a thermal conductivity about six times greater than nitrogen, it is concluded that the accelerated metabolism is in response to the greater heat loss in the presence of helium and the magnitude of this response is proportional to the thermal gradient between the animal and the environment.

Thermoregulation in Exercising White Rats

1973 ◽  
Vol 51 (11) ◽  
pp. 814-824 ◽  
Author(s):  
K. Myhre ◽  
B. Hellstrøm
Keyword(s):  
Thermal Stress ◽  
Skin Temperature ◽  
Albino Rats ◽  
Cold Environment ◽  
Exercise Time ◽  
Ambient Temperatures ◽  
Warm Environment ◽  
White Rats ◽  
Skin Temperatures ◽  
Trunk Skin

Colonic temperatures (TC), heart rates (HR), back skin and tail skin temperatures (TST) were measured in six warm acclimated (+24 °C) male albino rats running on a treadmill at three different work loads (HR ranging from 400 beats/min to 500 beats/min). Ambient temperatures (TA) ranged from about +8 °C to about +30 °C. TC increased immediately upon onset of work. Exercising in a cold environment ultimately made the rats hypothermic and in a warm environment hyperthermic. Within the limits set by the external thermal stress the rats controlled TC independently of the work intensity.High trunk skin temperatures were recorded in all experiments. Exercise in cold and cool environments produced tail skin vasoconstriction. In the 21 °C environment half of the rats produced tail skin vasodilation. In the 28 °C environment most experiments produced this effect. Cessation of work was accompanied by prompt vasoconstriction. The results indicated that exercise time before tail vasodilation was affected by exercise as well as by the tail skin temperature prior to vasodilation.

Thermal comfort in relation to mean skin temperature

1970 ◽  
Vol 48 (2) ◽  
pp. 98-101 ◽  
Author(s):  
E. D. L. Topliff ◽  
S. D. Livingstone
Keyword(s):  
Thermal Comfort ◽  
Ambient Temperature ◽  
Skin Temperature ◽  
Incident Radiation ◽  
Mean Skin Temperature ◽  
Ambient Temperatures ◽  
The Mean ◽  
Per Se

Nude men were exposed to a range of ambient temperatures and were brought to a condition of thermal comfort by adjustment of the incident radiation. The mean skin temperature associated with comfort was found to be different for each combination of ambient temperature and incident radiation. It was evident that mean skin temperature, per se, was not a dependable criterion of thermal comfort.

Hand-Skin Temperature and Dexterity

1979 ◽  
Vol 23 (1) ◽  
pp. 183-187
Author(s):  
Michael W. Riley ◽  
Denise M. Allison
Keyword(s):  
Ambient Temperature ◽  
Skin Temperature ◽  
Research Study ◽  
Measurement Methods ◽  
Industrial Worker ◽  
Male And Female ◽  
Assembly Task ◽  
Ambient Temperatures ◽  
Better Than ◽  
Female Subjects

This research study examined the dexterity performance of both male and female subjects at ambient temperatures of 35°, 55° and 75°F. Subjects wore typical industrial worker apparel without gloves. Four dexterity measurement methods were used. These were 1) Purdue Pegboard, 2) pencil point tapping, 3) an assembly task, and 4) a fine manipulative task. The subject's performance scores at the various tasks were correlated with the ambient temperature and the hand-skin temperature. Results indicate that females scored better than males on the Purdue Pegboard and a fine manipulative task at all temperatures, while males scored better in pencil point tapping and an assembly task.

Forearm blood flow during body temperature transients produced by leg exercise

1975 ◽  
Vol 38 (1) ◽  
pp. 58-63 ◽  
Author(s):  
C. B. Wenger ◽  
M. F. Roberts ◽  
J. A. Stolwijk ◽  
E. R. Nadel
Keyword(s):  
Blood Flow ◽  
Skin Temperature ◽  
Forearm Blood Flow ◽  
Bicycle Ergometer ◽  
Vapor Pressures ◽  
Internal Temperature ◽  
Ambient Temperatures ◽  
Forearm Skin ◽  
Leg Exercise ◽  
Skin Temperatures

Subjects exercised for 30 min on a bicycle ergometer at 30, 50, and 70% of maximal aerobic power in ambient temperatures of 15, 25, and 35 degrees C and vapor pressures of less than 18 Torr. Exercise was used to vary internal temperature during an experiment, and different ambient temperatures were used to vary skin temperatures independently of internal temperature. Forearm skin temperature was fixed at about 36.5 degrees C. Esophageal temperature (Tes) was measured with a thermocouple at the level of the left atrium, and mean skin temperature (Tsk) was calculated from a weighted mean of thermocouple temperatures at eight skin sites. Forearm blood flow (BF) was measured by electrocapacitance plethysmography. Our data are well accounted for by an equation of the form BF = a1Tes + q2Tsk + b, independent of exercise intensity, although some subjects showed an equivocal vasodilator effect of exercise. The ratios a1/a2 (7.5, 9.6, 11.7) are quite similar to the ratios (8.6, 10.4) of the corresponding coefficients in two recent models of thermoregulatory sweating.

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