• Journal of Nutrition and Health
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• v.1 no.1
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• pp.33-36
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• 1968

Amounts of heat production determined by two indirect calorimetric methods, i.e., respiration-calorimetric method and body balance method were compared. In this report the apparatus, its operation and computation procedures for Haldane respiration-calorimetry modified by Han as well as procedures for body balance method are described. It was found that the heat production measured by two methods are similar.

• Asian-Australasian Journal of Animal Sciences
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• v.11 no.4
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• pp.331-336
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• 1998

This review was conducted to analyse the effect of nutrition on physiological responses; heat production of domestic animal during exercise. Overall, it can be concluded that the major factors likely to affect heat production in domestic animals during exercise (including work load) are body weight, speed, the gradients attempted, feed intake, ambient conditions (including temperature and solar radiation) and altitude. On nutrition-exercise interactions, for example, it has been concluded that animals on better quality diets produce more heat than those on poorer quality ones, and that glucose as well as acetate are metabolized as energy sources during both rest and exercise.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.11
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• pp.1523-1528
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• 2000

Four Suffolk ewes were used in Latin Square switch over design to study the effects of varying levels and sources of protein on heat production and thermoregulatory responses at daytime high ($33^{\circ}C$ temperature. They were fed Italian ryegrass hay supplemented with fishmeal and/or urea, providing three different levels of crude protein (CP) (low/unsupplemented: 7.9, medium: 11.6, and high: 15.8%) at $1.5{\times}maintenance$. Feeds were distributed at 0900 (30%) and 1700 (70%). Urea diet caused higher heat production and increased vaginal temperature compared to fishmeal and fishmeal-urea mix diets. Time spent standing, skin temperature and respiration rate of sheep fed urea were similar with those of sheep fed fishmeal. Sheep fed diet with low CP level had higher heat production, increased vaginal and skin temperature than sheep fed diet with medium CP content. Sheep on high CP diet produced significantly more heat than sheep fed medium CP diets. Their vaginal temperatures were similar with those of sheep fed medium CP diet but lower than those of sheep fed low CP diet. Respiration rates of sheep and time spent by them for standing on all diets did not differ significantly. These results suggest that urea is inferior protein supplement for thermoregulation of animal at hot environment, as it induced higher heat production than fishmeal and fishmeal-urea mix. Thermoregulatory response on fishmeal-urea mix diet was similar to fishmeal diet. Increasing CP of the diet from low to medium gives advantage for thermoregulation of animal. Increasing CP further to high level was not beneficial as it resulted in the responses of sheep similar to those on low protein diet.

• Asian-Australasian Journal of Animal Sciences
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• v.2 no.3
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• pp.214-215
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• 1989

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.5
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• pp.625-629
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• 2000

Six yearling Suffolk ewes were used to study the effect of different roughage proportion diets (30%=LR, and 70%=HR) and intake levels (0.7 M and 1.3 M) on heat production and thermoregulatory responses in sheep exposed to different ambient temperatures (20 and $30^{\circ}C$). Sheep fed HR had higher heat production (HP) and time spent eating (TSE) and lower time spent standing (TSS) than those fed LR. But effect of roughage proportion on vaginal temperature (Tv) was obvious only at high intake and at $30^{\circ}C$. Sheep fed high intake had higher Tv, HP, TSS, and TSE than those fed low intake. Roughage proportion and intake level did not have an effect on respiration rate (RR), but ambient temperature did. Ambient temperature did not have an effect on HP, TSS and TSE. At $30^{\circ}C$ sheep had higher Tv and RR than those at $20^{\circ}C$. There were interactions between intake level and ambient temperature in TSS, between intake level and roughage proportion in TSE, and between roughage proportion and ambient temperature in HP. Results indicate that high roughage diet imposes a greater potential heat load on animals than low roughage diet when given at high ambient temperature, but not at low ambient temperature. And the effects is more pronounced at high intake.

• Asian-Australasian Journal of Animal Sciences
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• v.6 no.2
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• pp.275-279
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• 1993

A study using dairy heifers was conducted to determine the effect of environmental temperature on heat production differing in feed intake level. The design consisted of three levels of feed intake (low, medium and high) and two environmental chamber temperature (15 and $30^{\circ}C$) with four replications in each treatment. Rectal temperature (RT), respiration rate (RR), heart rate (HR) and heat production (HP) were then measured. At the both environmental temperature, RT, RR and HR increased with the increase in feed intake level. The RT and RR also increased with the elevation of environmental temperature. The HP of $30^{\circ}C$ was significantly higher (4.8-8.9%) than $15^{\circ}C$. The estimated metabolizable energy requirement for maintenance (MEm) was higher (p<0.05) at $30^{\circ}C$ ($554.7kJ/kg^{0.75}$ d) than $15^{\circ}C$ (464.9 kJ/kgd). It was suggested that the decreasing in productive efficiency under hot environmental conditions partly associated with the increase in HP, which associated with the change in heat loss mechanism from sensible path to evaporative path.

• Asian-Australasian Journal of Animal Sciences
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• v.7 no.2
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• pp.179-182
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• 1994

A study was conducted using four dairy heifers to determine the effect of 10, 20 and $30^{\circ}C$ environmental temperatures on the physiological responses and heat production, at a fixed level of TDN intake ($60.5\;g/kg^{0.75}\;d$). The analysis showed significant affects of environmental temperature on respiration rate (RR), mean body temperature (Tb), changes in body heat storage (S) and heat production (HP). The HP at $20^{\circ}C$ was almost the same as at $10^{\circ}C$, but the HP at $30^{\circ}C$ was 11% higher than at $10^{\circ}C$. A tendency for an elongation of standing time (ST) with the increase in environmental temperature was also observed. These results suggest that the increase in energy cost of elongation of ST ($9.2\;kJ/kg^{0.75}\;d$) and $1.3^{\circ}C$ increase in Tb ($17.3\;kJ/kg^{0.75}\;d$).

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.8
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• pp.1273-1276
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• 1999

Several reports have indicated that a rectal temperature of buffaloes is easily influenced by their surroundings. To clarify an effect of changing environmental temperature on thermoregulatory responses of buffaloes, an environment with diurnal temperature changes of $25^{\circ}C$ to $35^{\circ}C$ was created using an artificial climate laboratory. Three swamp buffaloes and three Friesian cows were exposed to three different experimental periods as follows: Period 1 (constant temperature of $30^{\circ}C$, Period 2 (diurnally changing temperature) and Period 3 (diurnally changing temperature and fasting). Heat production, rectal temperature, respiration rate, heart rate and respiration volume were measured during each period. Rectal temperature of the buffaloes fluctuated diurnally with the changing temperature (Periods 2 and 3), but remained constant in cows. Mean heat production was significantly lower in buffaloes than in cows in Period 2 and 3. However, the maximum rectal temperature and the increment of heat production were not always lower in buffaloes than in cows during Period 2. These results show that a rectal temperature and heat production in buffaloes are markedly influenced by the diurnal changes in temperature. Compared with Bos Taurus cows, the differences may be attributed to the physiological features of buffaloes including a high heat conductivity of their bodies and an lower heat production.

• Asian-Australasian Journal of Animal Sciences
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• v.4 no.3
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• pp.293-298
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• 1991

A study was conducted to determine the effect of environmental temperature and level of food intake on plasma concentration of thyroid hormones. Three dairy heifers were used in an experiment which consisted of three levels of chamber temperature (10, 20 and $30^{\circ}C$) and three levels of food intake (100, 75 and 50% of recommended requirements). The analysis showed significant effects of environmental temperature on plasma triiodothyronine concentration, rectal temperature, respiration rate and heart rate but not on heat production. The range of plasma triiodothyronine was 2.51~1.79 ng/ml when the environmental temperature varied from 10 to $30^{\circ}C$. Effects of feed intake level were significant for heart rate and heal production. Heat production decreased from 25.9 to $20.0kJ/kg^{0.75}{\cdot}h$ when the TDN intake decreased from 66.3 to $35.1g/kg^{0.75}{\cdot}d$. There was no interactive effect of environmental temperature and feed intake level. Plasma triiodothyronine concentration decreased under high environmental temperature without any changes in heat production. The effects of environmental temperature and feed intake level on the physiological function of thyroid gland, as indicated by the relative circulating rate of thyroid hormones, were found to be clear.

• Journal of the Korean Society of Clothing and Textiles
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• v.21 no.4
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• pp.669-676
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• 1997

The purpose of this study is to examine the effect of the improved cold tolerance resulting from cool clothing in winter on heat tolerance in summer. Ten healthy women were divided into two groups, cold group(C group) (n=5) and warm group(W group) (n=5) . In the previous study, C group was proved that their cold acclimatization was achieved through wearing cool clothing from September to February of the following year, while Wgroup was not proved because of wearing warm clothing during same period. After February, no more clothing training was continued in two groups. To determine the heat tolerance, both groups were exposed from a thermoneutral environment(25$\pm$1$^{\circ}C$, 50$\pm$5% R.H.) to a hot environment (35$\pm$1$^{\circ}C$, 50$\pm$5% R.H.) before and after clothing training, respectively September in 1994 and truly in 1995. Rectal temperature, skin temperatures, thermal sensation and comfort were measured every 10 min., and Os uptake was measured at 10, 45, 85 min. after entering the chamber for 5 min. Body weight was measured before and after the experiment and amount of local sweat was measured during the 90 min long experiment. The results are as follows: Rectal temperatures in 35'c environment of C group were increased after training when compared with before clothing, while those of W group were not changed. But the changes of rectal temperature and heat production during 90 min in hot environment were almost the same in two groups after training. And mean skin temperatures, the changes of mean skin temperatures during 90 min in hot environment, total sweat amount and local sweat amount after training were also the same in two groups. From these results, it might be supposed that the heat loss of two groups were the same but the heat production, especially heat production during rest in C group was higher than in Wgroup. This fact suggests that the increase of rest heat production from cold acclimatization in winter is maintained to summer of the following year. And mild cold acclimatization coming from westing cool clothing does not have a negative effect on heat tolerance.