Scaling of total evaporative water loss and evaporative heat loss in birds at different ambient temperatures and seasons

Pulmonary ventilation and temperature of expired air and of the respiratory passages has been measured by telemetry during flight in the black duck (Anas rubripes) and the respiratory water and heat loss has been calculated.During flight, temperature of expired air was higher than at rest and decreased with decreasing ambient temperatures. Accordingly, respiratory water loss as well as evaporative heat loss decreased at low ambient temperatures, whereas heat loss by warming of the inspired air increased. The data indicated respiratory water loss exceeded metabolic water production except at very low ambient temperatures. In the range between −16 °C to +19 °C, the total respiratory heat loss was fairly constant and amounted to 19% of the heat production. Evidence for the independence of total heat loss and production from changes in ambient temperature during flight is discussed.

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Studies of the environmental physiology of tropical merinos

Australian Journal of Agricultural Research ◽

10.1071/ar9780161 ◽

1978 ◽

Vol 29 (1) ◽

pp. 161 ◽

Cited By ~ 18

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.

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

Australian Journal of Zoology ◽

10.1071/zo9860035 ◽

1986 ◽

Vol 34 (1) ◽

pp. 35 ◽

Cited By ~ 33

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.

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Thermal Biology and Metabolism of the Greater Long-eared Bat, Nyctophilus major (Chiroptera :Vespertilionidae)

Australian Journal of Zoology ◽

10.1071/zo96043 ◽

1997 ◽

Vol 45 (2) ◽

pp. 145 ◽

Cited By ~ 8

Author(s):

D. J. Hosken

Keyword(s):

Water Loss ◽

Thermal Conductance ◽

Carbon Dioxide Production ◽

Evaporative Water Loss ◽

Detectable Effect ◽

Evaporative Water ◽

Ambient Temperatures ◽

Fat Reserves ◽

Metabolic Physiology ◽

Vespertilionid Bats

Nyctophilus major is the largest member of its Australian-centred genus. Flow-through respirometry was used to investigate the thermal and metabolic physiology of adult N. major from south-western Australia. Oxygen consumption, carbon dioxide production, respiratory quotient, evaporative water loss and thermal conductance were measured at ambient temperatures of 5–40C. N. major was thermally labile and could be euthermic or torpid at low Ta. N. major entered into and spontaneously aroused from torpor at Tas as low as 5C, and became torpid at Tas as high as 23C. Like other temperate-zone Australian vespertilionid bats, some torpid N. major maintained a relatively high Tb at low Ta. Body mass and the duration of captivity had no detectable effect on the thermal responses of bats. The basal metabolic rate (BMR) of N. major was 85% of predicted, and falls within the the range of mass-specific BMRs reported for vespertilionid bats. While mean torpid á VO2 was reasonably high, torpor still facilitates substantial metabolic savings. However, because of the high á VO2 , N. major may not be able to remain torpid for more than about 60 days, relying solely on fat reserves. The evaporative water loss (EWL) of euthermic and torpid N. major was also high, although EWL during torpor was reduced compared with euthermy. Wet conductance was lower than predicted and probably relates to the solitary, tree-roosting habits of N. major. As has been reported for other bats, conductance values during torpor were lower than those during euthermy, but when torpid bats maintained a large ( Tb – Ta) differential at low Ta or became torpid at relatively high Ta , conductance values approached euthermic levels.

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Ecology of Australian chats (Epthianura Gould) season movements, metabolism and ecaporative water loss

Australian Journal of Zoology ◽

10.1071/zo9760397 ◽

1976 ◽

Vol 24 (3) ◽

pp. 397 ◽

Cited By ~ 10

Author(s):

CK Williams ◽

AR Main

Keyword(s):

Water Loss ◽

Arid Regions ◽

Evaporative Water Loss ◽

Evaporative Water ◽

Seasonal Movements ◽

Ambient Temperatures ◽

Thermoneutral Zone ◽

Winter Temperatures ◽

Summer Temperatures ◽

Body Heat

The four species of Australian chats differ in their utilization of arid regions. Comparisons were made between the rates of metabolism and evaporative water loss of three species at moderate and high ambient temperatures, after trapping in the field during winter and after acclimation in the laboratory to 22�C and 14�C. When acclimated to winter temperatures the three species had similar rates of metabolism at moderate and high ambient temperatures. The rates of evaporative water loss at moderate temperatures were similar, but at temperatures above the thermoneutral zone the rates were lower in the more xeric than the more mesic species. When acclimated to summer temperatures the more xeric species had lower rates of metabolism and evaporative water loss than the more mesic species at temperatures within and above the thermoneutral zone. Variation in the rates of metabolism and evaporative water loss in field populations was greatest in the most mesic species and least in the most xeric species. Rates of metabolism and evaporative water loss were lower in all species after acclimation to 22�C than after acclimation to 14�C. The rates of metabolism and evaporative water loss tended to be lower than the rates predicted on the basis of body weight. In thermoregulation at high ambient temperatures the more xeric species evaporated relatively less body water in dissipating body heat than the more mesic species, apparently without a greater increase in body temperature. The ability of Australian chats to utilize semiarid and arid regions is explained by distributions and seasonal movements which complement the physiology of evaporative water loss and thermoregulation in a manner that enhances survival at high ambient temperatures.

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Thermoregulation, Oxygen-Consumption and Water Turnover in Stubble Quail, Coturnix-Pectoralis, and King Quail, Coturnix-Chinensis

Australian Journal of Zoology ◽

10.1071/zo9860025 ◽

1986 ◽

Vol 34 (1) ◽

pp. 25 ◽

Cited By ~ 19

Author(s):

JR Roberts ◽

RV Baudinette

Keyword(s):

Oxygen Consumption ◽

Body Temperature ◽

Ambient Temperature ◽

Water Loss ◽

Evaporative Water Loss ◽

Arid Areas ◽

Water Turnover ◽

Evaporative Water ◽

Ambient Temperatures ◽

Regulate Body Temperature

Stubble quail occur in more arid areas of Australia than king quail; however, the rates of metabolism and the ability to regulate body temperature in response to varying ambient temperature are similar in both birds, and resemble those of other quail species. At high ambient temperatures, rates of heat loss mediated by evaporative water loss are lower than those previously reported for more xerophilic species. Overall rates of water turnover and evaporative water loss at lower ambient temperatures are at the lower end of the range predicted for birds.

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

The Journal of Agricultural Science ◽

10.1017/s0021859600064947 ◽

1976 ◽

Vol 86 (1) ◽

pp. 35-43 ◽

Cited By ~ 24

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.

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Regulation of body temperature in the Budherygah, Melopsittacus undulatus

Australian Journal of Zoology ◽

10.1071/zo9760039 ◽

1976 ◽

Vol 24 (1) ◽

pp. 39 ◽

Cited By ~ 41

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.

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