The heat tolerance of two breeds of calves from 1 to 12 months of age.

1955 ◽  
Vol 6 (2) ◽  
pp. 350 ◽  
Author(s):  
GH Klemm ◽  
KW Robinson

Two grade Australian Illawarra Shorthorn bull calves and two Zebu- Hereford cross bull calves were exposed for 7 hr twice a week to each of several atmospheres having dry-bulb temperatures ranging from 86°F (30°C) to 108.5°F (42.5°C) and absolute humidities ranging from 6.5 to 16.6 gr moisture/cu.ft. dry air (vapour pressure 15-40 mm Hg). Such exposures were carried out a t different ages: 1-3 months, 6-8 months, and 12-13 months. The following reactions were studied: rectal temperature, pulse rate, respiratory rate, evaporative loss, skin temperature (Zebu-Hereford only), and behaviour. For air temperatures above 95°F the rise in rectal temperature was greater and equilibrium was reached more slowly in Illawarra Shorthorns than in the Zebu-Hereford. Increase in humidity at temperatures over 80°F produced more stress in the animals than increase of dry-bulb temperature. Pulse rates changed little during heat exposure, but there was a fall in rate with age under all circumstances. As the calves increased in age the panting rate decreased for a given hot environment (markedly so for the Zebu-Hereford crossbred). Evaporative loss increased as dry-bulb temperature was raised. The Zebu-Hereford showed a high transcutaneous water loss soon after birth with a continued increase up to 12 months. Skin evaporation was relatively small in the Illawarra Shorthorn at 1-2 months but increased a t 6-8 months, although it did not attain the high rate of the crossbred. In the Zebu-Hereford cross, sweat glands became active a t a skin temperature of approximately 96°F. With the onset of sweating a fall in skin temperature was observed. A comparison of the reactions of the Illawarra Shorthorn and the Zebu-Hereford crossbred with four Jersey calves aged 1-3 months, exposed to similar conditions by Riek and Lee, shows that the Zebu-Hereford has a better heat tolerance than either of the other breeds. Evidence is presented to indicate that this superiority of the Zebu crossbred is associated with at least two factors, ( a ) a better sweating mechanism and (b) decreased heat production. The Jersey and Illawarra Shorthorn calves have similar reaction values a t this age.

1953 ◽  
Vol 4 (2) ◽  
pp. 224 ◽  
Author(s):  
KW Robinson ◽  
GH Klemm

Four grade Australian Illawarra Shorthorn cows, aged 3 years, were exposed for 7 hr. twice a week to each of several atmospheres having dry-bulb temperatures ranging from 86° to 108.5°F. and absolute humidities ranging from 8 to 16 g./cu. ft. The following reactions were studied: rectal temperature, pulse rate, respiratory rate, evaporative loss, skin temperature, and behaviour. Average 9 a.m. ante-room rectal temperature reading was 101.5 ± 1.29°F. Dry-bulb temperatures of 95°F. and above caused a noticeable rise in rectal temperature and rise in body temperature paralleled rise in humidity. Humidity had a greater effect on the animal than dry-bulb temperature. Pulse rate was essentially unaffected by rise in temperature. Environmental conditions markedly influenced respiratory rate. On exposure to heat, the rate increased considerably before any rise in rectal temperature was apparent. When dry-bulb temperature increased, there was a parallel rise of evaporative loss with rise in respiratory rate. Humidity had little effect on water loss. Comparisons of the reactions of Australian Illawarra Shorthorn cows were made with four Jersey cows of similar age and lactation, exposed to atmospheric conditions similar to those observed by Riek and Lee two years previously. The following points were brought out: (i) The heat tolerance is greater in Jerseys with all combinations of dry- and wet-bulb temperatures. (ii) There is no significant change in pulse rate with breed. (iii) Respiratory rates are similar in the two breeds until the highest temperatures are reached, when that of the Illawarra Shorthorn increases above that of the Jersey. (iv) A greater increase in water loss occurs in the Jersey. (v) There is a larger body temperature-skin temperature gradient in the IIIawarra Shorthorn.


1962 ◽  
Vol 17 (5) ◽  
pp. 751-753 ◽  
Author(s):  
T. R. A. Davis

The seasonal changes in oxygen consumption, rectal temperature, and skin temperature in response to a 1-hr nude exposure to 14.1 C were measured once monthly in six subjects between October and February. The same measurements were obtained in another group nude exposed 8 hr daily to a chamber temperature of 13.5 C. Shivering decreased as a result of the seasonal and chamber cold exposure ( P < 0.01). Heat production also decreased as a result of both types of exposure ( P < 0.05) but never decreased to basal values. Skin temperature in the seasonal group exhibited no change, whereas a small fall occurred in the chamber group ( P < 0.05). Although no rectal temperature change was demonstrated in the seasonal group, there was a significant fall in the rectal temperature in the chamber group. After the period of chamber and seasonal cold acclimatization, both groups were subjected to 21 days of heat acclimatization followed by another cold-response measurement. In both groups the changes induced by winter exposure and chamber exposure were not influenced by heat exposure. Since previous studies have demonstrated the lack of influence of cold exposure on heat acclimatization, it is concluded that heat and cold acclimatization are not mutually exclusive and can exist simultaneously in man. Note: (With the Technical Assistance of D. R. Johnston, F. W. Jacks, and W. Rawlings) Submitted on October 6, 1961


1958 ◽  
Vol 50 (1) ◽  
pp. 73-81 ◽  
Author(s):  
G. C. Taneja

Three calves (Australian Illawara Shorthorn, Shorthorn and Zebu × Australian Illawara Shorthorn) were exposed to different combinations of wet- and dry-bulb temperatures in a psychrometric chamber at the Physiology Department of the University of Queensland. These animals were 2–3 months old when first exposed to heat.Measurements were made on these animals for cutaneous and respiratory water losses, and skin and rectal temperatures.Cutaneous water losses in all the animals studied increased with increases in air temperature. Comparing these results with those on men with congenital absence of sweat glands exposed to high air temperature below the sweat point, suggests that the cutaneous evaporative losses in cattle are more than those that can be accounted for by diffusionmoisture alone.Increase in cutaneous evaporation under hot conditions is accompanied by increase in skin and rectal temperatures. In the Zebu cross, however, the skin temperature did not rise with rise in air temperature.Keeping the humidity constant, rise in dry-bulb temperature caused increase in respiratory water loss. On the other hand, rising humidity at a constant dry-bulb temperature resulted in decrease in respiratory evaporation. Respiratory evaporative loss was, therefore, greater in hot-dry than in hot-wet conditions.


1959 ◽  
Vol 52 (1) ◽  
pp. 50-61 ◽  
Author(s):  
G. C. Taneja

1. Three female calves (Shorthorn, Zebux Australian Illawara Shorthorn, and American Brahman) of about 7–8 months old were exposed to different combinations of wet- and dry-bulb temperatures in the psychrometric chamber at the Physiology Department of the University of Queensland.2. A capsule method has been developed for measurement of cutaneous evaporation from limited areas. This method has been described in detail.3. Cutaneous evaporation from the shoulder area of the Zebu cross was significantly higher than that of the Shorthorn. There was, however, no difference between the two animals in their cutaneous evaporation from the belly area.4. In the Zebu cross the cutaneous water losses from the shoulder area, on the average, increased linearly with increase in skin temperature. In the Shorthorn, there was no important increase in the cutaneous evaporation from the shoulder area, although the skin temperature increased by about 2–3/ F.5. The Zebu cross had lower skin temperatures of the shoulder area when compared with that of the Shorthorn. These lower skin temperatures were associated with higher cutaneous evaporation.6. Increase in rectal temperature was not accompanied by increase in cutaneous evaporation in all the three animals studied.7. In all the three calves the cutaneous evaporation increased with increase in air temperature.


1963 ◽  
Vol 18 (1) ◽  
pp. 57-60 ◽  
Author(s):  
A. R. Lind

To define thermal limits for everyday work, a possible criterion which has been put forward described the climates (“prescriptive” climates) in which the level of bodily thermoregulation remained steady for a given rate of work. The present experiments were intended to determine the effect on results, obtained from brief exposures involving continuous work, of extending the exposure to a period of 8 hr and of presenting a given total energy expenditure (2,100 kcal) in different patterns of work and rest. During 8-hr exposures to three climates with dry and wet bulb temperatures of 29.4 and 23.9, 36.7 and 25.6, and 41.1 and 28.3 C, respectively, two subjects expended approximately 2,100 kcal in both 1) a nearly continuous level of activity and 2) intermittent bouts of much harder work interspaced by longer periods of rest. Evaluation and comparison of the results show that extension of exposures to periods of up to 8 hr per se did not demonstrably change the levels of rectal temperature, pulse rate, or weight loss found by the 2nd hr of exposure in the climates examined. Further, in prescriptive climates (in which the level of thermoregulation depends on the rate of work rather than on the environment), when the energy expenditure was 2,100 kcal in 8 hr, either continuously at a moderate rate, or intermittently at a high rate with compensatory rest pauses, the physiological cost was similar, as judged by rectal temperature, pulse rate, and weight loss. Submitted on June 15, 1962


Author(s):  
Andra DEGAN ◽  
Ruxandra TUDOR ◽  
Ruxandra COSTEA ◽  
Dragoș BÎRȚOIU ◽  
Mihai SĂVESCU ◽  
...  

General anesthesia produces different degrees of central nervous depression and changes in the peripheral circulation, therefore affecting the patient’s thermoregulatory mechanism. Moreover, the lack of proper, specially designed equipment for magnetic resonance imaging (MRI) environment monitoring can represent a challenge for the anesthetist. We examined the temperature variations correlated with different anesthetic protocols in dogs that underwent general anesthesia in order to evaluate changes in rectal and distal extremities temperature, before and after anesthesia. This study was conducted at the Faculty of Veterinary Medicine in Bucharest, on 21 dogs that were divided in 3 groups depending on the anesthetic protocol used. First group (B) received butorphanol (0.2 mg/kg, intravenously IV), second group (BK) had butorphanol (0.2 mg/kg) and a low dose of ketamine (2 mg/kg) IV, and group 3 (BM) was premedicated with butorphanol (0.2 mg/kg) and midazolam (0.2 mg/kg) IV. All patients were induced with propofol i.v. (3.24±0.68), intubated and maintained with isoflurane and oxygen. We determined rectal temperature before and right after the end of anesthesia with a digital thermometer and distal extremities temperature with the use of a thermal imaging camera attached to a smartphone. There was no significant difference between the rectal temperature before and after anesthesia within the 3 groups. Patients in group BK had a significant change in skin temperature at the end of anesthesia in all limbs (from 310C to 29.8 0C, p=0.008 and from 31 0C to 29.70C, p=0.009), respectively). Temperature variations were presented before and at the end of anesthesia, for all the groups especially at skin level. This study revealed that mobile thermal imaging represents a non-invasive technique that is helpful in assessing real time temperature changes in patients undergoing general anesthesia.


2019 ◽  
Vol 96 (9) ◽  
pp. 896-899
Author(s):  
S. M. Rasinkin ◽  
Viktoriya V. Petrova ◽  
M. M. Bogomolova ◽  
E. P. Gorbaneva ◽  
A. G. Kamchatnikov ◽  
...  

The article presents results of a study of the thermal stability in athletes during specific activities in hot climate. This happened on a training camp at the sports center, located in the district Sredneakhtubinsky of the Volgograd region with the registration of climate indices. The study was conducted in July at an effective temperature +44,6° - +45,4°C. The study involved 6 athletes, representatives of athletics, sports category on the following candidate for master of sports. During the endurance, training (cross) in athletes showed a significant increase in the rectal temperature (RT), average skin temperature (AST), average body temperature (ABT) against the background of the gain in the heart rate. During the training as "repeated cuts", the increase in indices of the thermal state in athletes also persisted, but their values were significantly lower than on the cross. The comparison of the dynamics of indices of the thermal state with the level of sports skills of each athlete showed the following features: the smallest gain in the rectal temperature, average skin temperature and average body temperature observed in cross-country race was observed in sportsman, whose level of training coach the evaluated as a minimal in the group. The highest gain in indices of the thermal state at the cross happened in the athlete with an average fitness level. Optimal gain in such indices as RT, AST and ABT was observed in the most prepared athlete. There was revealed a high level of adaptationness of athletes to the exposure to high temperatures. This is confirmed by the data of the evaluation of dynamics of subjective evaluation of warmth sense modality in athletes during the study period.


2009 ◽  
Vol 2009 ◽  
pp. 63-63
Author(s):  
S Khalajzade ◽  
N Emam Jomeh ◽  
A Salehi ◽  
A Moghimi Esfandabadi

Milk production is significantly decreased by thermal stress. The survival and performance of an animal during heat stress periods depend on several weather factors, especially temperature and humidity. Researchers reported dramatic decreases in milk production as temperature rose above 30 degree of centigrade. Very high environmental temperature is common during the summer months in Iran. Rectal temperature is as indicator of heat tolerance and has been the most frequently used physiological variable for estimating heat tolerance in cattle. Some dairy cows are more heat tolerant and productive when subjected to heat stress. Identification and selection of heat stress resistant cattle offers the potential to increase milk yield in tropical environment. The aim of the present study was to estimate genetic parameters of heat tolerance and its relationship to milk production in Holstein Dairy Cows in Iran.


1959 ◽  
Vol 14 (1) ◽  
pp. 43-45 ◽  
Author(s):  
M. B. Kreider ◽  
P. F. Iampietro ◽  
E. R. Buskirk ◽  
David E. Bass

Effects of continuous cold stress on 24-hour patterns of body temperature were studied in five men. Cold stress consisted in living at 15.6℃ (60℉) for 14 days wearing only shorts. The cold period was preceded and followed by 2 weeks at 26.7℃ (80℉). Activity (minimal) and diet were the same for all periods. One blanket was used at night. Rectal temperature (Tr) and skin temperature (Ts) were measured. Tr during sleep fell more rapidly and to lower values during cold exposure (35.6℃) than during the control period (36.1℃). Ts during sleep was slightly lower in the cold than in the control period; also, Ts did not exhibit the gradual drop characteristic of sleep in the control period. Comparison of Tr and Ts between early and later cold days revealed the following differences: a) nocturnal Tr fell to lower levels on the later cold days; b) nocturnal toe temperatures were 15℃ (27℉) higher on the later cold days. The arch temperatures followed the same pattern as the toes. No significant differences were found in daytime temperatures between early and later cold days. The data suggest that evidence for acclimatization to cold in terms of altered body temperature responses may be fruitfully sought in responses during rewarming and/or sleep. Submitted on September 19, 1958


1980 ◽  
Vol 48 (4) ◽  
pp. 657-664 ◽  
Author(s):  
V. A. Convertino ◽  
J. E. Greenleaf ◽  
E. M. Bernauer

Our purpose was to determine whether the chronic increase in plasma volume (PV), resulting from heat exposure (HE) and exercise training (ET), was due only to elevated rectal temperature (Tre) or whether there were additional nonthermal factors related to the exercise. Eight men were divided into two groups. The HE group sat for 2 h/day (Tdb = 42 degrees C, 93% rh) for 8 consecutive days; Tre was raised by 1.72 +/- 0.04 degrees C to 38.5 degrees C each day. The ET group rode a bicycle ergometer for 2 h/day for 8 days (Tdb = 25 degrees C, 60% rh) at a load (60-65 Vo2max) that gave the same area under their Tre curve. PV increased by 177 ml (4.9%, P less than 0.05) in the HE group and by 427 ml (12.0%, P less than 0.05) in the ET group. This exercise-induced hypervolemia was associated with thermal factor(s) that contributed 40% and nonthermal factors that accounted for the remaining 60%. Some nonthermal, exercise-induced factors were twofold greater increases in plasma osmotic and vasopressin levels during exercise, and a fivefold increase in resting plasma protein (albumin) content.


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