An improved water-bath test to study effects of age and previous sucking on metabolic rate and resistance to cold in newborn lambs

1990 ◽  
Vol 50 (2) ◽  
pp. 319-331 ◽  
Author(s):  
J. Slee ◽  
S. P. Simpson ◽  
A. W. Stott ◽  
J. C. Williams ◽  
D. E. Samson
Keyword(s):  
Body Weight ◽  
Metabolic Rate ◽  
Heat Production ◽  
Cold Resistance ◽  
Resting Metabolic Rate ◽  
Induced Hypothermia ◽  
Fast Cooling ◽  
Rate Of Cooling ◽  
Effect Of Age ◽  
Shivering Thermogenesis

ABSTRACTDifferent procedures for measuring cold resistance and metabolic rate of newborn lambs were evaluated by varying the extent of induced hypothermia, the rate of cooling and the method of rewarming. Relatively fast cooling followed by a simple self-rewarming procedure proved harmless and satisfactory.The effect of age, from birth up to 2 weeks, on thermoregulation was studied. There was no difference in cold resistance between 0·5 h and 30 h after birth, and between 1 day and 2 weeks after birth, despite a large increase in insulation, body weight and coat depth over this period. Weight-specific resting metabolic rate and cold-induced peak metabolic rate similarly did not change significantly in the first 30 h, although resting metabolic rate tended to be lower at birth than at 30 h of age. Peak metabolic rate decreased significantly between 1 day and 2 weeks of age.The effect of fasting, for 3 to 4 h after birth, on thermoregulation was also studied. Cold resistance and peak metabolic rate were not significantly affected by fasting. Recovery from hypothermia was slightly slower in fasted lambs.These results may reflect the newborn lamb's initial reliance on heat production derived from brown fat and non-shivering thermogenesis. Older lambs, which benefit from better insulation, rely more upon shivering. Fasted lambs showed a tendency to rely more on insulation and slightly less on heat production than suckled lambs.

Compensatory effect of the heat increment of feeding on thermoregulation costs of white-tailed deer fawns in winter

1999 ◽  
Vol 77 (9) ◽  
pp. 1474-1485 ◽  
Author(s):  
Paul G Jensen ◽  
Peter J Pekins ◽  
James B Holter
Keyword(s):  
Metabolic Rate ◽  
Heat Production ◽  
Resting Metabolic Rate ◽  
Energetic Cost ◽  
Critical Temperatures ◽  
Metabolic Chamber ◽  
Heat Increment Of Feeding ◽  
Heat Increment ◽  
Minor Portion ◽  
A Minor

For northern white-tailed deer (Odocoileus virginianus) fawns, the energetic cost of thermoregulation (HcE) during severe winters can result in substantial catabolism of body-tissue reserves. The heat increment of feeding (HiE) has the potential to offset thermoregulatory energy expenditure that would otherwise require the catabolism of these reserves. During winters 1996 and 1997, we conducted 18 fasting and 18 on-feed heat-production trials using indirect respiration calorimetry in a metabolic chamber. Nonlinear regression analysis was used to estimate the lower critical temperatures (Tlc) and determine the fasting metabolic rate (FMR) and resting metabolic rate (RMR). Resulting models were used to calculate HiE, HcE, and percent substitution of HiE for HcE. For fawns fed a natural browse diet, estimated FMR and RMR were 352 and 490 kJ·kg body mass (BM)-0.75·d-1, respectively; this 40% increase in thermoneutral heat production reduced Tlc from -0.8 to -11.2°C between the fasted and fed states, respectively, and reduced HcE by 59% for fed fawns. For fawns fed a concentrate diet, estimated FMR and RMR were 377 and 573 kJ·kg BM-0.75·d-1, respectively. Level of browse intake had a significant effect on RMR andTlc. RMR was 12% higher for fawns on a high versus a low level of intake, and estimated Tlc was -15.6 and -5.8°C, respectively. Our data indicate that the energetic cost of thermoregulation is probably a minor portion of the energy budget of a healthy fawn consuming natural forage.

The effects of litter size, sex, age, body weight, dam age and genetic selection for cold resistance on the physiological responses to cold exposure of scottish blackface lambs in a progressively cooled water bath

1987 ◽  
Vol 45 (3) ◽  
pp. 477-491 ◽  
Author(s):  
A. W. Stott ◽  
J. Slee
Keyword(s):  
Body Weight ◽  
Metabolic Rate ◽  
Cold Exposure ◽  
Cold Resistance ◽  
Genetic Selection ◽  
Water Bath ◽  
Skin Thickness ◽  
Selection Line ◽  
Unit Body Weight ◽  
Total Body

ABSTRACTThe resistance to body cooling of 594 newborn Scottish Blackface lambs was measured in a water bath during a programme of upwards and downwards genetic selection. Cold resistance was defined as the time taken for rectal temperature to fall to 35°C in the water bath.Upwards selection produced increased cold resistance which was genetically associated with increased skin thickness, increased total body insulation and greater persistence of high metabolic rate during cold exposure. The first two correlated responses to selection were more pronounced in twins than in singles.High cold resistance was phenotypically, but not genetically, associated with greater body weight, increased coat depth and higher levels of cold-induced metabolic rate (heat production). Single lambs showed higher weight-adjusted metabolic rates and higher cold resistance than twins. Singles recovered from hypothermia faster than twins in the low selection line only.Female lambs showed higher metabolic rate (whether weight-adjusted or not) and greater total body insulation than males. Their greater cold resistance was not quite significant. Increasing age (range 0·3 to 36 h) was associated with a small but significant decline in cold resistance.Thermoneutral metabolic rate was proportional to body surface area, whereas peak metabolic rate was proportional to body weight such that peak metabolic rate per unit body weight was independent of changes in body weight. These findings are discussed in relation to lamb survival.

A Twin Study Approach Towards Understanding Genetic Contributions to Body Size and Metabolic Rate

1991 ◽  
Vol 40 (2) ◽  
pp. 133-146 ◽  
Author(s):  
J.K. Hewitt ◽  
A.J. Stunkard ◽  
D. Carroll ◽  
J. Sims ◽  
J.R. Turner
Keyword(s):  
Body Weight ◽  
Metabolic Rate ◽  
Psychological Stress ◽  
Resting Metabolic Rate ◽  
Genetic Effect ◽  
Set Point ◽  
Study Approach ◽  
Brief Assessment ◽  
High Heritability ◽  
Genetic Contributions

AbstractThe genetic and environmental determinants of a brief assessment of metabolic rate at rest and under psychological stress were studied in 40 pairs of monozygotic and 40 pairs of dizygotic young adult male twins. Height, weight and age were employed as covariates. Univariate analyses showed a high heritability for height and weight and moderate heritability for metabolic rate. Classical twin analyses and multivariate genetic modeling indicated that genetic influences on resting metabolic rate were entirely explained by body weight: there was no independent genetic contribution to resting metabolic rate. Metabolic rate under psychological stress, on the other hand, showed a significant genetic effect. The exponent (3/4) in the power function relating body weight to resting metabolic rate was the same as that found in a wide variety of animal species, a value that has been proposed as defining a body weight set point. We speculate that an adult body weight set point is genetically transmitted. Independent genetic effects on resting metabolic rate would be observed only when the normal equilibrium between body weight and metabolic rate is unbalanced during development, aging or disease. The study illustrates the use of multivariate genetic analyses of twin data which may be readily applied to widely used metabolic rate assessments.

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

scholarly journals Effect of Age on Body Water and Resting Metabolic Rate

1996 ◽  
Vol 51A (2) ◽  
pp. M71-M73 ◽  
Author(s):  
N. K. Fukagawa ◽  
L. G. Bandini ◽  
W. H. Dietz ◽  
J. B. Young
Keyword(s):  
Metabolic Rate ◽  
Resting Metabolic Rate ◽  
Body Water ◽  
Effect Of Age

ÉTUDE DE L'ACCLIMATION THERMIQUE CHEZ LA LIMACE ARION CIRCUMSCRIPTUS

1963 ◽  
Vol 41 (4) ◽  
pp. 671-698 ◽  
Author(s):  
Adolphe Roy
Keyword(s):  
Body Weight ◽  
Oxygen Consumption ◽  
Metabolic Rate ◽  
Heat Production ◽  
Regression Line ◽  
Experimental Temperature ◽  
Acclimation Temperature ◽  
Direct Calorimetry

Slugs of the species Arion circumscriptus were acclimated to temperatures of 5°, 8° 10°, 20°, and 25 °C respectively. After acclimation, metabolic rate was determined, either as oxygen consumption, at 30° and 20°, or by direct calorimetry, at 25° and 12.5°, At all given exposure temperatures, the average metabolic rate was lower, by 1% to 1.5%, for each degree of increase in the acclimation temperature. When the logarithms of total O2 consumption or heat production per hour are plotted against the logarithms of body weight, the regression line obtained for slugs acclimated to heat stands below that obtained for slugs acclimated to cold; the slope is also slighter for the warm-acclimated slugs than for the cold-acclimated, so that the distance between corresponding points of two such curves is larger in the righthand side of the graph, where the large specimens are represented, than in the lefthand side where the small specimens are shown. This would imply that an increase in the acclimation temperature reduces metabolic rate to a proportionately greater extent in the larger specimens than it does in the smaller ones. The value of the slope, which is inversely correlated with acclimation temperature, is also inversely correlated with the experimental temperature at which metabolism is determined.

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