The heat production of oiled mallards and scaup

1973 ◽  
Vol 51 (1) ◽  
pp. 27-31 ◽  
Author(s):  
E. H. McEwan ◽  
A. F. C. Koelink
Keyword(s):  
Critical Temperature ◽  
Metabolic Rate ◽  
Ambient Temperature ◽  
Heat Loss ◽  
Heat Production ◽  
Normal Values ◽  
Thermal Conductance ◽  
Water Repellency ◽  
Regression Analyses ◽  
Lower Critical Temperature

A measure of the thermal conductance of the plumage of normal and oiled ducks was determined from regression analyses that related metabolic rate and ambient temperature. The heat loss of heavily oiled mallards and scaup was 1.7 and 2 times greater than their normal values, respectively. Oiling not only tended to increase the basal heat production, but also shifted the lower critical temperature from 12 to 25C. Attempts to rehabilitate the scaup after oiling and cleaning were rarely successful because of plumage deterioration and the loss of water repellency.

scholarly journals Laboratory Metabolism of Incubating Semipalmated Plovers

The Condor ◽  
2006 ◽  
Vol 108 (4) ◽  
pp. 966-970
Author(s):  
Mark Williamson ◽  
Joseph B. Williams ◽  
Erica Nol
Keyword(s):  
Critical Temperature ◽  
Metabolic Rate ◽  
Breeding Season ◽  
Basal Metabolic Rate ◽  
Low Temperatures ◽  
Thermal Conductance ◽  
Basal Metabolism ◽  
The Arctic ◽  
Lower Critical Temperature ◽  
Metabolic Data

Abstract Abstract The Semipalmated Plover (Charadriussemipalmatus), anarctic-nesting migratory shorebird, regularlyencounters low temperatures during the breedingseason. We measured the basal metabolism of adultsduring incubation at Churchill, Manitoba, Canada todetermine basal metabolic rate (BMR),lower critical temperature(Tlc), total evaporative waterloss (TEWL), and dry thermal conductance(Cm). BMR and Tlcwere 47.4 kJ day−1and 23.3°C, respectively, TEWL was2.5 mL H2O−d,and Cm was1.13 mW g−1 °C−1.Measured BMR and Tlc were consistentwith high values found for other shorebird speciesbreeding in the Arctic, while Cm was18% higher than predicted from allometricequations. These metabolic data suggest thatSemipalmated Plovers are adapted to balance therequirements of incubation against energetic andthermoregulatory demands in the Arctic, especiallyin harsh early breeding season conditions.

Further studies on the heat production and effective lower critical temperature of early-weaned pigs under commercial conditions of feeding and management

1984 ◽  
Vol 39 (2) ◽  
pp. 283-290 ◽  
Author(s):  
K. J. McCracken ◽  
R. Gray
Keyword(s):  
Critical Temperature ◽  
Heat Production ◽  
Thermal Conductance ◽  
Open Circuit ◽  
Weaned Pigs ◽  
Respiration Chamber ◽  
Lower Critical Temperature ◽  
The Mean ◽  
The Difference ◽  
Practical Implications

ABSTRACTIn two separate experiments pigs were weaned at 14 or 28 days and heat production was determined in an open-circuit respiration chamber at temperatures above and below the lower critical temperature (Tcl) at intervals during the post-weaning period.With 14-day weaned pigs the mean 24 h heat production above Tc1 averaged 267, 328, 474 and 554 kJ/h per m2 at 3, 9, 15 and 21 days post weaning respectively. The mean thermal conductance (H/AT, kJ/h per m2 per °ΔT, where H is total heat production, m2 is the surface area calculated as 0·097 M kg0·633 and °Δ is the difference between rectal temperature, taken at 39°, and air temperature) below TC1 was calculated as 20·5, 20·1, 23·1 and 24·2 at 17, 23, 29 and 35 days of age respectively and the corresponding values for Tc1 were 25·9, 23·0, 18·4 and 16·0°C.With 28-day weaned pigs the mean 24 h heat production above Tc1 averaged 280, 361 and 445 kJ/h per m2 at 3, 9 and 15 days post weaning. The calculated values for H/ΔT were 19·7, 20·8 and 21·6 and the corresponding values of Tcl were 24·8, 21·7, and 18·8°C at 31, 37 and 43 days of age respectively.The results are discussed in relation to previous studies on 10-day and 28-day weaned pigs and in relation to the practical implications for pigs weaned into controlled-environment accommodation.

scholarly journals Studies on diurnal variations of heat production and the effective lower critical temperature of early-weaned pigs under commercial conditions of feeding and management

1980 ◽  
Vol 43 (2) ◽  
pp. 321-328 ◽  
Author(s):  
K. J. McCracken ◽  
B. J. Caldwell
Keyword(s):  
Critical Temperature ◽  
Heat Production ◽  
Thermal Conductance ◽  
Open Circuit ◽  
Respiration Chamber ◽  
Mean Values ◽  
Maximum Value ◽  
Lower Critical Temperature ◽  
The Mean ◽  
The Difference

1. The heat production of groups of pigs, weaned at 10 d of age, was determined in an open-circuit respiration chamber at various ages between 10 and 33 d at temperatures above and below the lower critical temperature (Tcl).2. The heat production was lowest on the second or third day post weaning when pigs were given feed increasing by 25 g/pig per d from day 2. There was a marked diurnal pattern in heat production, the lowest values being recorded between 24.00 and 08.00 h.3. The mean thermal conductance (H/ΔT, kJ/h per m2 per °ΔT, where His total heat production, m2 is the surface area calculated as 0.097 W kg0.633 (Brody, 1945) and °ΔTis the difference between rectal temperature, taken as 39°, and air temperature) below Tcl was calculated as 18.0, 16.9, 18.5 and 21.2 respectively at 10, 17, 24 and 31 d of age. Maximum values of H/ΔT obtained during feeding periods were. on average, 4.5 kJ/h per me per °ΔT higher than the mean values.4. The maximum value for Tcl during the immediate post-weaning period was 25.9°. The mean Tcl at 17, 24 and 31 d were respectively 21.7, 18.4 and 18.6° for pigs fed almost to appetite.

Shivering and nonshivering thermogenic responses of rats subjected to different patterns of heat acclimation

1993 ◽  
Vol 71 (8) ◽  
pp. 576-581 ◽  
Author(s):  
Sohtaro Sakurada ◽  
Osamu Shido
Keyword(s):  
Adipose Tissue ◽  
Critical Temperature ◽  
Ambient Temperature ◽  
Brown Adipose Tissue ◽  
Heat Production ◽  
Heat Exposure ◽  
Control Group ◽  
Interscapular Brown Adipose Tissue ◽  
Brown Adipose ◽  
Lower Critical Temperature

Male Wistar rats were divided into five groups: a control group kept at an ambient temperature of 24 °C for 14 days, and four heat-acclimated groups (two groups subjected to a constant ambient temperature of 33 °C for 4 days or 14 days (HC-14) immediately preceding the measurement; and another two groups subjected to an ambient temperature of 33 °C for about 5 h once a day for 4 days, or 14 days (HI-14) just prior to the measurement). After the completion of the schedule, the rats were placed in a temperature-controlled chamber. Hypothalamic (Thy) and interscapular brown adipose tissue (TBAT) temperatures, oxygen consumption [Formula: see text], and shivering activity were measured during a gradual fall in temperature of a water jacket surrounding the chamber (Tw) from 30 to 10 °C at a constant rate of 0.18 °C/min. During the fall in Tw, [Formula: see text] and TBAT increased significantly and shivering was induced without associate changes in Thy in all groups. Tw at the onset of a rise in metabolic heat production (onset of cold-induced thermogenesis) coincided with that at the onset of a rise in TBAT (onset of BAT thermogenesis), but was significantly higher than that at the onset of shivering. In HC-14 and HI-14 rats, Tws at the onset of cold-induced thermogenesis and BAT thermogenesis were significantly higher than those in control rats, whereas Tws at the onset of shivering were not different from those in control rats. The onset of cold-induced thermogenesis did not change after the 4-day heat exposure. These results suggest that heat exposure for 14 days, regardless of the pattern, shifts the lower critical temperature to a high level, and the changes are attributed to an upward shift in the ambient temperature at which nonshivering thermogenesis occurs.Key words: heat exposure, heat production, brown adipose tissue, lower critical temperature.

SEASONAL ACCLIMATIZATION IN VARYING HARE (LEPUS AMERICANUS)

1965 ◽  
Vol 43 (5) ◽  
pp. 731-744 ◽  
Author(s):  
J. S. Hart ◽  
Hermann Pohl ◽  
J. S. Tener
Keyword(s):  
Critical Temperature ◽  
Ambient Temperature ◽  
Heat Loss ◽  
Seasonal Changes ◽  
Evaporative Heat Loss ◽  
Total Heat Loss ◽  
Seasonal Differences ◽  
Seasonal Acclimatization ◽  
Lower Critical Temperature ◽  
Approximate Equality

Wild hares were trapped in the vicinity of Ottawa, Canada, and tested during summer and winter. After recovery from implantation of subcutaneous and substernal thermocouples, measurements of oxygen uptake and body temperatures were made during successive stepwise lowering of ambient temperature from 20 °C to −45 °C over about 5 hours. Measurements were also made during stepwise elevation of temperature from 12 °C to 38 °C over a 5-hour period and a final single test was made at 40 °C.Hares trapped during the winter had lower O2 uptake than did summer-caught hares at temperatures below thermal neutrality. The change was very similar in magnitude to the seasonal change in insulation of the fur (27% greater in winter). The lower critical temperature was shifted from +10 °C in summer hares to about −5 °C in winter hares.No seasonal differences were noted in substernal temperatures, but subcutaneous temperatures were significantly higher in winter-caught animals. Colonic temperatures were higher than substernal temperatures at all ambient temperatures.Electromyograms recorded from the mid-back showed that shivering was greater in the cold during summer than during winter in accordance with the higher O2 consumption at any given temperature. Shivering was also slightly greater during summer at the same level of O2 consumption.Varying hares showed a considerable tolerance to elevation of temperature and a capacity to maintain approximate equality of body and ambient temperature at 40 °C for some time through effective respiratory evaporative heat loss, which approached 100% of heat production. Stepwise elevation of ambient temperature did not reveal any seasonal differences in upper critical temperature (about 38 °C) or in elevation of body temperature in spite of differences in insulation of the fur. A slightly greater proportion of the total heat loss was by evaporation during the summer.Caloric intake of captive hares outdoors was similar during winter and summer. It is concluded that seasonal acclimatization in the varying hare is largely insulative with respect to cold and that changes in heat tolerance are minor if present at all. Insulative and behavioral modifications appear to compensate for seasonal changes in temperature in the Ottawa area.

Do metabolism and contour plumage insulation vary in response to seasonal energy bottlenecks in superb fairy-wrens?

2006 ◽  
Vol 54 (1) ◽  
pp. 23 ◽  
Author(s):  
Alan Lill ◽  
Jeffrey Box ◽  
John Baldwin
Keyword(s):  
Critical Temperature ◽  
Metabolic Rate ◽  
Thermal Conductance ◽  
Whole Body ◽  
Ambient Temperatures ◽  
The North ◽  
General Metabolism ◽  
Lower Critical Temperature ◽  
Heat Conservation ◽  
Low Altitude

Many small birds living at mid-to-high latitudes in the North Temperate Zone display seasonal increases in general metabolism and plumage insulation. We examined whether superb fairy-wrens at low altitude in temperate Australia, where winter is milder and the winter–spring transition less pronounced, exhibited similar adjustments. Their oxygen-consumption rate at ambient temperatures in and below their thermoneutral range was measured overnight in winter, spring and summer. Contour plumage mass was also compared in individuals caught in all seasons of the year. Resting-phase metabolic rate in the thermoneutral zone did not vary seasonally. The relationship between ambient temperature and whole-body metabolic rate below lower critical temperature differed in summer and winter, but the regression for spring did not differ from those for summer or winter. Plumage mass was greater (4.04% v. 2.64% of body mass) and calculated whole-bird wet thermal conductance lower (1.55 v. 2.24 mL O2 bird–1 h–1 °C–1) in winter than in summer. Enhanced plumage insulation could have improved heat conservation in autumn and winter. No increase in standard metabolism occurred in winter, perhaps because this season is relatively mild at low altitude in temperate Australia. However, superb fairy-wrens at 37°S operated below their predicted lower critical temperature for most of winter and the early breeding season, so they have presumably evolved as yet unidentified mechanisms for coping with the energy bottlenecks encountered then.

Thermoregulation in the only nocturnal simian: the night monkey Aotus trivirgatus

1981 ◽  
Vol 240 (3) ◽  
pp. R156-R165 ◽  
Author(s):  
Y. Le Maho ◽  
M. Goffart ◽  
A. Rochas ◽  
H. Felbabel ◽  
J. Chatonnet
Keyword(s):  
Critical Temperature ◽  
Metabolic Rate ◽  
Response Pattern ◽  
Thermal Environment ◽  
Resting Metabolic Rate ◽  
Thermal Conductance ◽  
Open Circuit ◽  
The Body ◽  
Thermoneutral Zone ◽  
Lower Critical Temperature

The night monkey, a tropical monkey, is the only nocturnal simian; its thermoregulation was studied for comparison with other nocturnal or diurnal primates and other tropical mammals. Resting metabolic rate was 2.6 W (closed-circuit method) and 2.8 W (open-circuit method), 24 and 18% below the value predicted from body mass. The thermoneutral zone was very narrow; the lower critical temperature (LCT) was 28 degrees C and the upper critical temperature (UCT) was 30 degrees C. The body temperature (Tb) was at its minimum (38 degrees C) at an ambient temperature (Ta) of 25 degrees C, thus below the LCT. At low Ta, the increase in metabolic rate (MR) was smaller than predicted by the Scholander model, since MR intersected to a Ta 13 degrees C above Tb when extrapolated to MR = 0; this was attributed to a decrease of body surface area by behavior. The thermal conductance at the LCT was low: 2.3 W . m-2 . degrees C-1. Above the UCT, panting was the major avenue of heat loss. The response pattern of nocturnal habits, low resting metabolic rate, low thermal conductance, and panting in the night monkey, unique among simians, is found in many other mammals of tropical and hot desert habitats; it may be considered as an alternative adaptation to the thermal environment.

Thermoregulation of African and European Honeybees during Foraging, Attack, and Hive Exits and Returns

1979 ◽  
Vol 80 (1) ◽  
pp. 217-229 ◽  
Author(s):  
HEINRICH BERND
Keyword(s):  
Metabolic Rate ◽  
Ambient Temperature ◽  
Heat Loss ◽  
Warm Up ◽  
Ambient Temperatures ◽  
Thoracic Temperature

1. While foraging, attacking, or leaving or returning to their hives, both the African and European honeybees maintained their thoracic temperature at 30 °C or above, independent of ambient temperature from 7 to 23 °C (in shade). 2. Thoracic temperatures were not significantly different between African and European bees. 3. Thoracic temperatures were significantly different during different activities. Average thoracic temperatures (at ambient temperatures of 8–23 °C) were lowest (30 °C) in bees turning to the hive. They were 31–32 °C during foraging, and 36–38 °C in bees leaving the hive, and in those attacking. The bees thus warm up above their temperature in the hive (32 °C) before leaving the colony. 4. In the laboratory the bees (European) did not maintain the minimum thoracic temperature for continuous flight (27 °C) at 10 °C. When forced to remain in continuous flight for at least 2 min, thoracic temperature averaged 15 °C above ambient temperature from 15 to 25 °C, and was regulated only at high ambient temperatures (30–40 °C). 5. At ambient temperatures > 25 °C, the bees heated up during return to the hive, attack and foraging above the thoracic temperatures they regulated at low ambient temperatures to near the temperatures they regulated during continuous flight. 6. In both African and European bees, attack behaviour and high thoracic temperature are correlated. 7. The data suggest that the bees regulate thoracic temperature by both behavioural and physiological means. It can be inferred that the African bees have a higher metabolic rate than the European, but their smaller size, which facilitates more rapid heat loss, results in similar thoracic temperatures.

Regulation of metabolic rate in Svalbard and Norwegian reindeer

1984 ◽  
Vol 247 (5) ◽  
pp. R837-R841 ◽  
Author(s):  
K. J. Nilssen ◽  
J. A. Sundsfjord ◽  
A. S. Blix
Keyword(s):  
Body Weight ◽  
Critical Temperature ◽  
Food Intake ◽  
Metabolic Rate ◽  
Seasonal Changes ◽  
Serum Levels ◽  
Physiological Adaptation ◽  
Conservation Of Energy ◽  
Winter Food ◽  
Lower Critical Temperature

Food intake, body weight, serum levels of triiodothyronine (T3) and free thyroxine (FT4), and metabolic rate were measured at intervals in Svalbard (SR) and Norwegian (NR) reindeer. From summer to winter food intake decreased 57 (SR) and 55% (NR), while body weight decreased 8.6 (SR) and 3.8% (NR). In SR T3 and FT4 changed seasonally, whereas this was only evident for T3 in NR. Resting (standing) metabolic rate (RMR) in winter was 1.55 (SR) and 2.05 W X kg-1 (NR), lower critical temperature (TLC) being -50 (SR) and -30 degrees C (NR). RMR in summer was 2.15 (SR) and 2.95 W X kg-1 (NR), TLC being -15 (SR) and 0 degrees C (NR). Seasonal changes in T3 and FT4 did not coincide with changes in food intake or RMR in either SR or NR. RMR did, however, correlate with food intake. This indicates that seasonal changes in RMR are due to the thermic effects of feeding and represent no physiological adaptation aimed at conservation of energy during winter.

Temperature regulation and cold acclimation in the golden hamster

1965 ◽  
Vol 20 (3) ◽  
pp. 405-410 ◽  
Author(s):  
Hermann Pohl
Keyword(s):  
Oxygen Consumption ◽  
Body Temperature ◽  
Ambient Temperature ◽  
Cold Acclimation ◽  
Heat Production ◽  
Golden Hamster ◽  
Thermal Conductance ◽  
Muscular Activity ◽  
The Body ◽  
Ambient Temperatures

Characteristics of cold acclimation in the golden hamster, Mesocricetus auratus, were 1) higher metabolic rate at -30 C, 2) less shivering when related to ambient temperature or oxygen consumption, and 3) higher differences in body temperature between cardiac area and thoracic subcutaneous tissues at all ambient temperatures tested, indicating changes in tissue insulation. Cold-acclimated hamsters also showed a rise in temperature of the cardiac area when ambient temperature was below 15 C. Changes in heat distribution in cold-acclimated hamsters suggest higher blood flow and heat production in the thoracic part of the body in the cold. The thermal conductance through the thoracic and lumbar muscle areas, however, did not change notably with lowering ambient temperature. Marked differences in thermoregulatory response to cold after cold acclimation were found between two species, the golden hamster and the thirteen-lined ground squirrel, showing greater ability to regulate body temperature in the cold in hamsters. hibernator; oxygen consumption— heat production; body temperature — heat conductance; muscular activity — shivering; thermoregulation Submitted on July 6, 1964

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