Aquatic thermoregulation of captive and free-ranging beavers (Castor canadensis)

1990 ◽  
Vol 68 (11) ◽  
pp. 2409-2416 ◽  
Author(s):  
Robert A. MacArthur ◽  
Alvin P. Dyck
Keyword(s):  
Metabolic Rate ◽  
Cold Water ◽  
Castor Canadensis ◽  
Resting Metabolic Rate ◽  
Whole Body ◽  
Passive Cooling ◽  
Metabolic Rates ◽  
The Mean ◽  
Free Ranging ◽  
Skin Temperatures

Abdominal cooling occurred in 91% of all aquatic excursions documented in free-ranging beavers during fall and winter. Kits aged 4–7 months cooled faster and spent less time foraging in 1–12 °C water than did animals > 1 year old. All beavers tested in the laboratory displayed abdominal cooling in 2–20 °C water, with maximal cooling rates recorded in a 5- to 7-week-old kit. Immersion in cold water induced strong peripheral cooling, though skin temperatures beneath the pelage remained within 4–5 °C of abdominal measurements. The resting metabolic rate of beavers > 1 year old was independent of water temperature between 19 and 31 °C, but increased proportionately at lower temperatures. Whole-body conductance of resting animals was on average 1.6–3.0 times higher in water than in air. Maximum testing metabolic rates in water varied from 1.8 to 2.4 times the mean resting thermoneutral rate in air. Our results suggest that beavers mitigate the thermogenic effort required in water by adopting a thermoregulatory strategy which combines avoidance of prolonged immersion with a tolerance to passive cooling.

scholarly journals SUMMIT METABOLISM OF NEWBORN CALVES WITH AND WITHOUT COLOSTRUM FEEDING

1986 ◽  
Vol 66 (4) ◽  
pp. 937-944 ◽  
Author(s):  
M. OKAMOTO ◽  
J. B. ROBINSON ◽  
R. J. CHRISTOPHERSON ◽  
B. A. YOUNG
Keyword(s):  
Body Weight ◽  
Metabolic Rate ◽  
Rectal Temperature ◽  
Cold Water ◽  
Water Immersion ◽  
Resting Metabolic Rate ◽  
The Body ◽  
Metabolic Rates ◽  
Colostrum Feeding ◽  
Time Required

Resting and summit metabolic rates were measured in 13 newborn (2.5–15 h old) male Holstein calves exposed to warm and cold tempertures in a water immersion system. Six calves were bottle fed 1 kg of colostrum 30 min before the measurements commenced. In the remaining seven calves, colostrum was withheld until after the end of the measurement period. There were no significant effects of colostrum feeding on resting or summit metabolic rates or the time required for rectal temperature to drop to 35 °C when the calves were immersed in cold water. The time required for rectal temperature to drop to 35 °C increased as the body weight of the calves increased; for each kilogram additional body weight, cooling was delayed for an extra 2.9 min. The resting metabolic rate averaged for both feeding treatments was 2.0 ± 0.1 W kg−1 while mean rectal temperature was 39.1 ± 0.2 °C. Mean summit metabolic rate was 7.2 ± 0.4 W kg−1 and occurred at a mean rectal temperature of 35.4 ± 0.3 °C. The average ratio of the summit to resting metabolic rate was 3.7 ± 0.2. Cooling via water immersion was associated with increases in plasma levels of glucose and free fatty acids. The feeding of 1 kg of colostrum 30 min prior to exposure to acute cold did not improve the apparent resistance of the calves to hypothermia. Key words: Newborn calf, summit metabolism, cold tolerance

The ontogeny of metabolic rate and thermoregulatory capabilities of northern fur seal, Callorhinus ursinus, pups in air and water

2000 ◽  
Vol 203 (6) ◽  
pp. 1003-1016 ◽  
Author(s):  
M.J. Donohue ◽  
D.P. Costa ◽  
M.E. Goebel ◽  
J.D. Baker
Keyword(s):  
Metabolic Rate ◽  
Developmental Stages ◽  
Resting Metabolic Rate ◽  
Thermal Conductance ◽  
Open Circuit ◽  
Whole Body ◽  
Callorhinus Ursinus ◽  
Metabolic Rates ◽  
Northern Fur Seal ◽  
Fur Seal

Young pinnipeds, born on land, must eventually enter the water to feed independently. The aim of this study was to examine developmental factors that might influence this transition. The ontogeny of metabolic rate and thermoregulation in northern fur seal, Callorhinus ursinus, pups was investigated at two developmental stages in air and water using open-circuit respirometry. Mean in-air resting metabolic rate (RMR) increased significantly from 113+/−5 ml O(2)min(−)(1) (N=18) pre-molt to 160+/−4 ml O(2)min(−)(1) (N=16; means +/− s.e.m.) post-molt. In-water, whole-body metabolic rates did not differ pre- and post-molt and were 2.6 and 1.6 times in-air RMRs respectively. Mass-specific metabolic rates of pre-molt pups in water were 2.8 times in-air rates. Mean mass-specific metabolic rates of post-molt pups at 20 degrees C in water and air did not differ (16.1+/−1.7 ml O(2)min(−)(1)kg(−)(1); N=10). In-air mass-specific metabolic rates of post-molt pups were significantly lower than in-water rates at 5 degrees C (18.2+/−1.1 ml O(2)min(−)(1)kg(−)(1); N=10) and 10 degrees C (19.4+/−1.7 ml O(2)min(−)(1)kg(−)(1); N=10; means +/− s.e.m.). Northern fur seal pups have metabolic rates comparable with those of terrestrial mammalian young of similar body size. Thermal conductance was independent of air temperature, but increased with water temperature. In-water thermal conductance of pre-molt pups was approximately twice that of post-molt pups. In-water pre-molt pups matched the energy expenditure of larger post-molt pups while still failing to maintain body temperature. Pre-molt pups experience greater relative costs when entering the water regardless of temperature than do larger post-molt pups. This study demonstrates that the development of thermoregulatory capabilities plays a significant role in determining when northern fur seal pups enter the water.

Energy metabolism and thermoregulation of beaver (Castor canadensis)

1989 ◽  
Vol 67 (3) ◽  
pp. 651-657 ◽  
Author(s):  
Robert A. MacArthur
Keyword(s):  
Critical Temperature ◽  
Castor Canadensis ◽  
Resting Metabolic Rate ◽  
Whole Body ◽  
Metabolic Rates ◽  
Body Temperatures ◽  
Thermoneutral Zone ◽  
Air Temperatures ◽  
Lower Critical Temperature ◽  
Predicted Values

Metabolic rates and body temperatures (Tb) of adult and immature beavers were recorded at air temperatures from −20 to 28 °C. The thermoneutral zone of beavers > 1 year of age extended from 0–2 °C to at least 28 °C. Lower critical temperature, whole-body conductance, and resting metabolic rate were similar for yearlings and beavers ≥ 2 years old, and conformed closely to weight-predicted values for terrestrial eutherians. The estimated lower critical temperature of a growing beaver kit declined from 24–25 °C at 2–3 weeks of age when the animal weighed 0.59–0.62 kg to 0–2 °C at 11–13 weeks when the kit weighed 2.92–3.50 kg. Rectal Tb of the kit was generally lower and less stable than abdominal Tb recorded telemetrically from older animals. In beavers > 1 year old, abdominal Tb was independent of air temprature (−20 to 28 °C), with no evidence of hypothermia or metabolic depression at subfreezing temperatures. Neither the level nor the daily rhythm of Tb was substantially altered by 24–48 h fasting in this species.

Energy expenditure in free-ranging sagebrush lizards (Sceloporus graciosus)

1982 ◽  
Vol 60 (6) ◽  
pp. 1412-1416 ◽  
Author(s):  
Justin D. Congdon ◽  
Donald W. Tinkle
Keyword(s):  
Metabolic Rate ◽  
Body Mass ◽  
Resting Metabolic Rate ◽  
Metabolizable Energy ◽  
Activity Level ◽  
Metabolic Rates ◽  
Daily Energy ◽  
Sceloporus Graciosus ◽  
Field Metabolic Rates ◽  
Free Ranging

Metabolic rates of free-ranging Sceloporus graciosus (Sauria: Iguanidae) were measured during the summer using doubly labeled H2O. Adults of either sex and juveniles did not differ in field metabolic rates (0.26 mL CO2∙g−1∙h−1or 160 J∙g−1∙day−1). Field metabolic rates were 2.4 times the resting metabolic rate, and activity respiration was 3.1 times the resting metabolic rate at lizard activity temperatures. Activity accounted for 59% of the energy consumption due to respiration. Calculated rates of feeding indicated a 415 J∙day−1 deficit in metabolizable energy intake, and this was reflected in rate of loss of body mass throughout the study. Daily energy harvested by 200 lizards (31 kJ∙day−1), which approximates densities (per hectare) on the study area, would supply only 40% of the daily energy requirements of one insectivorous bird with similar body mass and activity level of a Phainopepla (79 kJ∙day−1).

Effect of altitude on dietary-induced thermogenesis at rest and during light exercise in man

1978 ◽  
Vol 45 (3) ◽  
pp. 345-349 ◽  
Author(s):  
M. J. Stock ◽  
N. G. Norgan ◽  
A. Ferro-Luzzi ◽  
E. Evans
Keyword(s):  
Metabolic Rate ◽  
Specific Dynamic Action ◽  
Metabolic Rates ◽  
Postprandial Metabolism ◽  
Interindividual Differences ◽  
Liquid Meal ◽  
The Mean ◽  
Monte Rosa ◽  
Hypoxic Exercise ◽  
Made In

Measurements of metabolic rate and the thermic response (specific dynamic action) of a 400-kcal liquid meal were made in six subjects at rest and during light exercise. The tests were conducted before (LA1) and after (LA2) a 3-wk sojourn (HA1, HA2, HA3) at 3,650 m on the Monte Rosa. Fasting metabolic rate at rest increased inittally and then fell, as did fasting and fed exercising metabolic rates. The fall in metabolic rates, but not the initial increases, can be ascribed to the change in body weight. Resting thermic responses at altitude were only slightly lower than normal, although peak values were significantly depressed at HA2 (P less than 0.05). The mean exercising thermic response was also significantly lower at HA2 (P less than 0.05) but recovered in HA3 and LA2. In the time taken for thermic responses to decrease and recover there were interindividual differences that were best explained by the previous altitude experience of the subjects. The possibility of a cardiovascular shift during hypoxic exercise causing depression of postprandial metabolism is discussed.

scholarly journals Two Novel Models Evaluating the Determinants of Resting Metabolic Rate in Indian Children

2021 ◽  
Author(s):  
Sandra Aravind Areekal ◽  
Anuradha Khadilkar ◽  
Veena Ekbote ◽  
Neha Kajale ◽  
Arun S. Kinare ◽  
...  
Keyword(s):  
Body Composition ◽  
Metabolic Rate ◽  
Resting Metabolic Rate ◽  
Childhood Development ◽  
Relative Mass ◽  
Kidney Volume ◽  
Indian Children ◽  
Cross Sectional ◽  
Multi Centre Study ◽  
The Mean

Abstract Resting metabolic rate (RMR) quantifies the minimal energy required to sustain vital body functions and is a crucial component of childhood development. While inter-individual variations in RMR have been studied for over a century they are poorly understood. Wang (Am. J. Hum., 2012) has modelled mean RMR per unit body mass (RMR/BM) in children grouped into age classes one year apart; this model is able to explain the variation in RMR/BM very accurately in a reference Caucasian dataset based on the relative masses of four major organs (liver, kidney, brain, heart) and the residual mass. However, it is not clear if it applies to other ethnicities, especially when the variation in the RMR is observed to be large in a population. Here we address the extent to which such a model can be adapted to explain RMR/BM in Indian children. Here we present two novel phenomenological models that describe the mean RMR/BM stratified by age in Indian children and adolescents, using data from the Multi-Centre Study (MCS) and RMR-USG. MCS is a cross-sectional dataset on 495 (235 girls) children aged 9 to 19 years with anthropometric, body composition and RMR measurements. RMR-USG consists of anthropometric data, RMR, and liver and kidney volume measured through ultrasonography in nine girls and nine boys aged 6 to 8 years. The mean RMR/BM in Indian children is observed to be significantly lower compared to their Caucasian counterparts, except in boys in the age groups 9 to 11 years and 12 to 13 years. The first is a modified Wang model in which the relative masses of four major organs are assumed to be uniformly lowered for Indian children. Theoretical predictions of size are not uniformly borne out in a pilot validation study, however, the relative mass of the kidney is indeed found to be significantly lower. We then present another version of the Wang model to demonstrate that changes in body composition alone can also explain the Indian data. Either model can be thus used phenomenologically to estimate mean RMR/BM by age in Indian children; however, understanding the mechanistic basis of variation in RMR/BM remains an open problem.

Foraging energetics and diving behavior of lactating New Zealand sea lions, Phocarctos hookeri

2000 ◽  
Vol 203 (23) ◽  
pp. 3655-3665 ◽  
Author(s):  
D.P. Costa ◽  
N.J. Gales
Keyword(s):  
New Zealand ◽  
Metabolic Rate ◽  
Dive Depth ◽  
Diving Behavior ◽  
Metabolic Rates ◽  
Sea Lion ◽  
Water Turnover ◽  
Sea Lions ◽  
The Mean ◽  
Phocarctos Hookeri

The New Zealand sea lion, Phocarctos hookeri, is the deepest- and longest-diving sea lion. We were interested in whether the diving ability of this animal was related to changes in its at-sea and diving metabolic rates. We measured the metabolic rate, water turnover and diving behavior of 12 lactating New Zealand sea lions at Sandy Bay, Enderby Island, Auckland Islands Group, New Zealand (50 degrees 30′S, 166 degrees 17′E), during January and February 1997 when their pups were between 1 and 2 months old. Metabolic rate (rate of CO(2) production) and water turnover were measured using the (18)O doubly-labeled water technique, and diving behavior was measured with time/depth recorders (TDRs). Mean total body water was 66.0+/−1.1 % (mean +/− s.d.) and mean rate of CO(2) production was 0. 835+/−0.114 ml g(−)(1)h(−)(1), which provides an estimated mass-specific field metabolic rate (FMR) of 5.47+/−0.75 W kg(−)(1). After correction for time on shore, the at-sea FMR was estimated to be 6.65+/−1.09 W kg(−)(1), a value 5.8 times the predicted standard metabolic rate of a terrestrial animal of equal size. The mean maximum dive depth was 353+/−164 m, with a mean diving depth of 124+/−36 m. The mean maximum dive duration was 8.3+/−1.7 min, with an average duration of 3.4+/−0.6 min. The deepest, 550 m, and longest, 11.5 min, dives were made by the largest animal (155 kg). Our results indicate that the deep and long-duration diving ability of New Zealand sea lions is not due to a decreased diving metabolic rate. Individual sea lions that performed deeper dives had lower FMRs, which may result from the use of energetically efficient burst-and-glide locomotion. There are differences in the foraging patterns of deep and shallow divers that may reflect differences in surface swimming, time spent on the surface and/or diet. Our data indicate that, although New Zealand sea lions have increased their O(2) storage capacity, they do not, or cannot, significantly reduce their at-sea metabolic rates and are therefore likely to be operating near their physiological maximum.

Resting and field metabolic rates of Awassi sheep and Baladi goats raised by Negev bedouin

2020 ◽  
Vol 158 (5) ◽  
pp. 431-437
Author(s):  
Michael Kam ◽  
Shaher El-Meccawi ◽  
Arieh Brosh ◽  
A. Allan Degen
Keyword(s):  
Metabolic Rate ◽  
Resting Metabolic Rate ◽  
Arid Areas ◽  
Metabolic Rates ◽  
Herbaceous Vegetation ◽  
Sheep And Goats ◽  
Awassi Sheep ◽  
Natural Pasture ◽  
Field Metabolic Rates ◽  
The Cost

AbstractSheep are grazers and goats are intermediate feeders. By employing O2 consumption and heart rate measurements, resting metabolic rate (RMR) and field metabolic rate (FMR) were determined in four male fat-tailed Awassi sheep (44.0 ± 3.94) and four male Baladi goats (35.5 ± 5.42 kg) that were co-grazing natural pasture in the Negev Desert. There were 67.7 ± 3.75 g DM/m2 of herbaceous vegetation biomass, which was rapidly becoming senescent and more fibrous. We hypothesized that FMR of these desert-adapted ruminants would be relatively low when compared to other sheep and goat breeds, as animals in arid areas tend to have low metabolic rates. Both sheep (n = 6) and goats (n = 6) foraged 71% of the allotted 11 h free-pasture period; however, sheep grazed more than goats (P < 0.001); whereas goats browsed more than sheep (P < 0.001). RMR was higher (P = 0.007) in sheep than in goats (529 ± 23.5 v. 474 ± 25.4 kJ/kg0.75 BW/d), but FMR did not differ between species (618 ± 55.7 v. 613 ± 115.2 kJ/kg0.75 BW/d). In addition, the cost of activities, as a proportion of FMR, did not differ between sheep and goats; FMR increased by 89 kJ/kg0.75 BW/d or 17% in sheep and by 138 kJ/kg0.75 BW/d or 29% in goats. In comparing FMRs of sheep and goats in this study with these species in other studies, differences were inconsistent and, therefore, our hypothesis was not supported.

Metabolic Rate of Female Rats as a Function of Age and Body Size

1956 ◽  
Vol 186 (1) ◽  
pp. 9-12 ◽  
Author(s):  
Max Kleiber ◽  
Arthur H. Smith ◽  
Theodore N. Chernikoff
Keyword(s):  
Body Weight ◽  
Body Size ◽  
Metabolic Rate ◽  
Age Groups ◽  
Female Rats ◽  
Standard Errors ◽  
Normal Female ◽  
Metabolic Rates ◽  
The Mean ◽  
Specific Unit

On the basis of 926 respiration trials, metabolic rates of normal female rats are presented as means of 42 different age groups from birth to 1000 days of age. The means with their standard errors are given for the metabolic rates per rat, per kilogram weight, per unit of the 2/3 power of body weight (surface), and per unit of the 3/4 power of body weight (inter specific unit of metabolic body size). A minimum of 72.6 Cal/kg.3/4 occurs between the ages of 200 and 300 days. An equation with two exponentials predicts the metabolic rate of rats from 77–1000 days of age with a standard deviation between prediction and observation of 2.2% of the mean.

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