The effects of temperature and relative humidity on the thermoregulatory responses of grouped and isolated neonate chicks

1976 ◽  
Vol 86 (1) ◽  
pp. 35-43 ◽  
Author(s):  
B. H. Misson
Keyword(s):  
Body Size ◽  
Relative Humidity ◽  
Rectal Temperature ◽  
Heat Production ◽  
Water Loss ◽  
Evaporative Heat Loss ◽  
Evaporative Water ◽  
Ambient Temperatures ◽  
Metabolic Heat ◽  
Effects Of Temperature

SUMMARYMeasurements of O2 consumption (Vo2), CO2 production (VCO2) evaporative water loss and rectal temperature (Tr) have been made and metabolic heat production (H), evaporative heat loss (—E) and respiratory quotient (RQ) calculated with individual and groups of 1-day-old chicks at constant ambient temperatures (To) in the range 20—43 °C and 80 or 20% relative humidity (R.H.).Minimal metabolism (10·7 kJ/kgJ/h) occurred at 35 °C.One-day-old chicks act as heterotherms outside the zone of minimal metabolism since neither H nor —E are sufficiently developed mechanisms to maintain homeothermy.Huddling allows chicks to maintain a higher TT at a lower H per unit metabolic body size.Reducing E.H. from 80 to 20% raised the upper temperature survival limit (UTSL) from 41·5 to 43 °C.Panting was initiated when Ta = 38 °C and Tr was between 39·5 and 39·9 °C.

Effects of phentolamine on thermoregulatory functions of rats to different ambient temperatures

1979 ◽  
Vol 57 (12) ◽  
pp. 1401-1406 ◽  
Author(s):  
M. T. Lin ◽  
Andi Chandra ◽  
T. C. Fung
Keyword(s):  
Heat Loss ◽  
Rectal Temperature ◽  
Heat Production ◽  
Room Temperature ◽  
Metabolic Heat Production ◽  
Central Component ◽  
Evaporative Heat Loss ◽  
Central Administration ◽  
Ambient Temperatures ◽  
Metabolic Heat

The effects of both systemic and central administration of phentolamine on the thermoregulatory functions of conscious rats to various ambient temperatures were assessed. Injection of phentolamine intraperitoneally or into a lateral cerebral ventricle both produced a dose-dependent fall in rectal temperature at room temperature and below it. At a cold environmental temperature (8 °C) the hypothermia in response to phentolamine was due to a decrease in metabolic heat production, but at room temperature (22 °C) the hypothermia was due to cutaneous vasodilatation (as indicated by an increase in foot and tail skin temperatures) and decreased metabolic heat production. There were no changes in respiratory evaporative heat loss. However, in the hot environment (30 °C), phentolamine administration produced no changes in rectal temperature or other thermoregulatory responses. A central component of action is indicated by the fact that a much smaller intraventricular dose of phentolamine was required to exert the same effect as intraperitoneal injection. The data indicate that phentolamine decreases heat production and (or) increases heat loss which leads to hypothermia, probably via central nervous system actions.

Regulation of body temperature in the Budherygah, Melopsittacus undulatus

1976 ◽  
Vol 24 (1) ◽  
pp. 39 ◽  
Author(s):  
WW Weathers ◽  
DC Schoenbaechler
Keyword(s):  
Body Temperature ◽  
Heat Production ◽  
Water Loss ◽  
Standard Metabolic Rate ◽  
Evaporative Water Loss ◽  
Metabolic Heat Production ◽  
Evaporative Water ◽  
Ambient Temperatures ◽  
Metabolic Heat ◽  
Metabolic Water

The standard metabolic rate of budgerygahs, determined during October and November, was 30% lower at night (1.96 ml O2 g-1 h-1) than during the day (2.55 ml O2 g-1h-1 ). The zone of thermal neutrality extended from 29 to 41�C. At ambient temperatures (Ta) below 29�C, oxygen consumption [V(02)] increased with decreasing Ta according to the relation V(02) (ml O2 g-1 h-1) = 5.65 - 0.127Ta. At Ta's between 0 and 16�C, body temperature (Tb) averaged 37.7�C (which is low by avian standards) and was independent of Ta. Above 20�C, Tb increased with increasing Ta, and within the zone of thermal neutrality Tb increased by approximately 4�C. The relation between V(O2) and Tb within the zone of thermal neutrality is described by the equation V(O2 = 6.29 - 0.105 Tb. This ability to decrease metabolic heat production while Tb rises could contribute to the water economy of budgerygahs. At moderate Ta's the rate of evaporative water loss of budgerygahs is only 60% that predicted for a 31 g bird. At Ta's below 14�C budgerygahs can balance evaporative water loss with metabolic water production. At 45�C Tb was between 1.0 and 5.0�C below Ta, and evaporative cooling accounted for up to 156% of metabolic heat production. At high Ta's budgerygahs appear to augment evaporation by lingual flutter.

scholarly journals Heat Production From Foraging Activity Contributes to Thermoregulation in Black-Capped Chickadees

The Condor ◽  
2007 ◽  
Vol 109 (2) ◽  
pp. 446-451 ◽  
Author(s):  
Sheldon J. Cooper ◽  
Sarah Sonsthagen
Keyword(s):  
Heat Production ◽  
Water Loss ◽  
Thermal Conductance ◽  
Metabolic Heat Production ◽  
Foraging Activity ◽  
Poecile Atricapillus ◽  
Evaporative Water ◽  
Ambient Temperatures ◽  
Metabolic Heat ◽  
Locomotor Muscles

AbstractWe measured metabolic heat production (H ˙m) of perching and foraging Black-capped Chickadees (Poecile atricapillus) to determine if the heat produced during foraging activity, or exercise thermogenesis, could replace thermoregulatory heat production requirements. H ˙m and activity of chickadees in winter were measured at ambient temperatures (Ta) ranging from −11.5° to 15.5°C. Mean activity amplitude recorded with an activity detector was significantly higher in foraging birds than perching birds. H ˙m did not vary significantly between perching and foraging birds, indicating that heat produced during foraging does substitute for heat produced by shivering for thermoregulation. Evaporative water loss and dry thermal conductance did not vary significantly between perching and foraging chickadees. These results suggest that heat produced from locomotor muscles during foraging activity substitutes for thermoregulatory requirements in glean-and-hang foraging species, such as chickadees, as well as in ground-foraging birds.

Studies of the environmental physiology of tropical merinos

1978 ◽  
Vol 29 (1) ◽  
pp. 161 ◽  
Author(s):  
PS Hopkins ◽  
GI Knights ◽  
AS Le Feuvre
Keyword(s):  
Low Temperature ◽  
Rectal Temperature ◽  
Water Loss ◽  
Heat Dissipation ◽  
Evaporative Water Loss ◽  
Compensatory Mechanisms ◽  
Evaporative Water ◽  
Ambient Temperatures ◽  
Diurnal Patterns ◽  
Made In

Rectal temperature measurements of tropical Merino sheep taken in the sun during summer indicated that there were high and low temperature groups. Animals of low temperature status (e.g. 39.4°C) also exhibited a low respiration rate (e.g. 110/min) in comparison with their less adapted counterparts (40.0° and 190/min). These differences were greatest when ambient temperatures were high. The repeatability of temperature status was 0.46 (P < 0.01). Animals of folds (+) phenotype had significantly higher rectal temperatures than folds (–) animals (P < 0.05). Shearing caused a marked but transient increase in rectal temperature. Compensatory mechanisms apparently involved an increase in cutaneous heat dissipation and/or a decrease in exogenous heat load. Evaporative water loss (80–115 ml/kg/day) greatly exceeded the non-evaporative water loss (40–65 ml/kg/day) of sheep in metabolism cages. Respiratory water loss could account for only 8–10% of the total daily evaporative water loss. Non-respiratory evaporative water loss (as measured by difference) was c. 75–100 ml/kg/day. There were no striking differences between high and low temperature status sheep in this regard. Measurements of respiratory (2 ml/kg/hr) and non-respiratory (5.5 ml/kg/hr) evaporative water loss made in hygrometric tents suggested that the greater non-respiratory water loss was partly due to a higher rate of loss and partly to a longer period of loss per day. This suggestion was supported by the diurnal patterns of rectal temperatures and respiration rates reported here, though no firm conclusions could be made as to the thermotaxic effect of non-respiratory water loss and thermoregulation of tropical Merinos with varying amounts of wool cover.

Energetics of the Little Penguin, Eudyptula Minor: Temperature Regulation, the Calorigenic Effect of Food, and Moulting.

1986 ◽  
Vol 34 (1) ◽  
pp. 35 ◽  
Author(s):  
RV Baudinette ◽  
P Gill ◽  
M O'driscoll
Keyword(s):  
Heat Production ◽  
Water Loss ◽  
Thermal Conductance ◽  
Fold Increase ◽  
The Body ◽  
Evaporative Water Loss ◽  
Evaporative Water ◽  
Ambient Temperatures ◽  
Effect Of Food ◽  
Little Penguin

Rates of oxygen consumption and means of augmenting the resultant heat production were studied in the little penguin, Eudyptula minor. Metabolic rates were lower than those predicted for a 1-kg bird, but shivering and an energy response to feeding were both present. The latter effect was independent of ambient temperatures between 2 deg and 22 deg C. The birds have limited ability to dissipate heat by evaporative water loss. About 40% of the total heat production was the maximum amount lost by this route. Cooling of expired respiratory gas provided an effective saving of heat and water. Moulting resulted in a 1.5-fold increase in metabolic rate but rates of evaporative water loss were reduced. The increase in heat production is correlated with increased thermal conductance across the body surface, as new feathers are synthesized, but body temperature is the same as in non-moulting penguins. The results suggest that increased heat loss when the birds are in water might be replaced by calorigenesis associated with the response to feeding, and by shivering, as well as by activity.

Effect of ketamine on thermoregulation in rats

1978 ◽  
Vol 56 (6) ◽  
pp. 963-967 ◽  
Author(s):  
M. T. Lin ◽  
C. F. Chen ◽  
I. H. Pang
Keyword(s):  
Drug Treatment ◽  
Skin Temperature ◽  
Rectal Temperature ◽  
Heat Production ◽  
Intraperitoneal Administration ◽  
Metabolic Heat Production ◽  
Ambient Temperatures ◽  
Metabolic Heat ◽  
Dose Dependent ◽  
Skin Temperatures

Intraperitoneal administration of ketamine produced dose-dependent hypothermia at the ambient temperatures (Ta) of both 8 and 23 °C in unanesthetized rats. At a Ta of 8 °C, the hypothermia was brought about solely by a decrease in metabolic heat production. There were no changes in either the tail skin temperature (Ttail) or the sole skin temperature (Tsole). At a Ta of 23 °C, the hypothermia was due to an increase in Ttail, an increase in Tsole, and a decrease in metabolic heat production. However, at a Ta of 31 °C, there were no changes in rectal temperature in response to ketamine application, since neither heat production nor skin temperatures (e.g., Ttail and Tsole) was affected by ketamine at this Ta. The data indicate that the effect of the drug treatment may be to decrease heat production and (or) increase heat loss.

scholarly journals Thermoregulatory role of insensible evaporative water loss constancy in a heterothermic marsupial

2017 ◽  
Vol 13 (11) ◽  
pp. 20170537 ◽  
Author(s):  
Christine Elizabeth Cooper ◽  
Philip Carew Withers
Keyword(s):  
Relative Humidity ◽  
Water Loss ◽  
Physiological Role ◽  
Vapour Pressure Deficit ◽  
Evaporative Water Loss ◽  
Regulatory Control ◽  
Water Vapour Pressure ◽  
Evaporative Water ◽  
Ambient Temperatures

‘Insensible’ evaporative water loss of mammals has been traditionally viewed as a passive process, but recent studies suggest that insensible water loss is under regulatory control, although the physiological role of this control is unclear. We test the hypothesis that regulation of insensible water loss has a thermoregulatory function by quantifying for the first time evaporative water loss control, along with metabolic rate and body temperature, of a heterothermic mammal during normothermia and torpor. Evaporative water loss was independent of ambient relative humidity at ambient temperatures of 20 and 30°C, but not at 25°C or during torpor at 20°C. Evaporative water loss per water vapour pressure deficit had a positive linear relationship with relative humidity at ambient temperatures of 20 and 30°C, but not at 25°C or during torpor at 20 or 25°C. These findings suggest that insensible water loss deviates from a physical model only during thermoregulation, providing support for the hypothesis that regulation of insensible evaporative water loss has a thermoregulatory role.

Mechanisms of thermal balance in flying Centris pallida (Hymenoptera: Anthophoridae).

1998 ◽  
Vol 201 (15) ◽  
pp. 2321-2331 ◽  
Author(s):  
S P Roberts ◽  
J F Harrison ◽  
N F Hadley
Keyword(s):  
Heat Transfer ◽  
Water Balance ◽  
Heat Production ◽  
Water Loss ◽  
Thermal Effects ◽  
Negative Relationship ◽  
Metabolic Heat Production ◽  
Wingbeat Frequency ◽  
Evaporative Water ◽  
Metabolic Heat

Thermoregulation of the thorax is critical for bees and other endothermic insects to achieve high rates of flight muscle power production. However, the mechanisms allowing insects to regulate thorax temperatures during flight are not well understood. To test whether variations in metabolic heat production, evaporation or heat transfer from the thorax to the abdomen contribute to the maintenance of stable body temperatures during flight in the bee Centris pallida, we measured CO2 production, water vapor loss, wingbeat frequency and body segment temperatures during flight at varying air temperatures (Ta). While hovering in the field and while flying in the respirometer, C. pallida males maintain extremely stable, elevated thorax temperatures (45+/-2 degrees C; mean +/- S.E.M.). Measurements of head, thorax and abdomen temperatures as a function of Ta during hovering flight in the field indicated that C. pallida males were not actively increasing heat transfer from the thorax to the head or abdomen at high Ta values. As Ta increased from 26 to 35 degrees C, increases in evaporative water loss were relatively small compared with the decrease in carbon dioxide emission. As Ta values increased from 26 to 35 degrees C, the factorial decreases in metabolic heat production and the elevation of thorax temperature above Ta were closely matched (35 %), suggesting that variation in metabolic heat production is the major mechanism of thermoregulation in flying C. pallida. The thermal effects on rates of water loss and metabolic water production resulted in a strong positive water balance at cooler Ta values, but a strong negative water balance at Ta values above 31 degrees C. During the first minute of flight in the respirometry chamber, wingbeat frequency was independent of Ta. However, by the fourth minute, there was a significant negative relationship between Ta and wingbeat frequency, which was similar to the thermal relationship observed for wingbeat frequency in the field. These data suggest that, either through homeostatic regulation or resulting secondarily from thermal effects on flight motor properties, variation in metabolic heat production may occur via altered wingbeat kinematics.

Sign in / Sign up

Export Citation Format

Share Document