On the calculation of heat production from open-circuit calorimetric measurements

. 2000. Effect of water restriction and environmental temperatures on metabolic rate and physiological parameters in sheep. Can. J. Anim. Sci. 80: 97-104. The hypothesis that water restriction reduces metabolic rate and contributes to energy conservation of sheep, and induces changes in blood parameters was tested. Four of eight adult sheep were housed in either a warm (24.8 ± 1.5°C) or cold (0.4 ± 1.2°C) environment and fed a diet of alfalfa pellets at 1.2 × maintenance. Each sheep was fasted with or without water according to a crossover design. Average heat production (HP) and rectal temperature (Tr) were higher (P < 0.05) in the cold than in the warm. Fasting decreased HP and Tr (P < 0.05). Water restriction had no additional effect on HP and Tr. Fasting and fasting plus water restriction influenced plasma osmolality and creatinine concentration. Plasma creatinine concentration was lower (P < 0.01) and haemoglobin (Hb) concentration higher in the cold than in the warm environment. Hb concentration was increased with water restriction (P < 0.01) in the warm environment. Plasma cortisol concentration was altered by fasting. Packed cell volume (PCV) in blood, plasma volume and plasma aldosterone were not affected by treatments. The results suggest that water restriction, per se, for 3 d does not suppress metabolic rate in sheep below that resulting from fasting alone. Chaque mouton était ensuite mis au jeûne pendant trois jours, avec ou sans eau, selon un dispositif avec permutation des traitements. La production de chaleur moyenne (PCh) et la température rectale (Tr) étaient plus élevées (P < 0,05) dans l'ambiance froide que dans la chaude. Le jeûne, seul ou avec restriction d'abreuvement, influait sur l'osmolarité et sur la concentration de créatinine du plasma. En outre, ce dernier paramètre était plus bas (P < 0,01) dans l'ambiance froide, alors que l'inverse s'observait pour la concentration d'hémoglobine (Hb) dans le sang. La concentration de Hb augmentait, quand l'eau était rationnée (P < 0,01), dans l'ambiance chaude. La concentration plasmatique de cortisol était modifiée par suite du jeûne de solide. L'hématocrite (HCT), le volume de plasma et la concentration d'aldostérone plasmatique ne manifestaient pas de réaction aux traitements. Il ressort des observations que à lui seul le rationnement de l'eau pendant 3 jours n'a pas plus d'effet négatif sur la thermogenèse chez le mouton que le jeûne solide seul.Mots clés: Thermogenèse, mouton, température, rationnement de l'eau Changes in the thermal environment induce a variety of physiological responses in animals (Christopherson and Kennedy 1983). Metabolic rate is increased during cold exposure in sheep (Christensen et al. 1990), and also during the period of heat stress in cattle (Miaron et al. 1995). Therefore, energy requirements of animals are increased in a cold environment and also during acute heat stress (Miaron et al. 1995). However, there is evidence that a portion of increased energy expenditure in response to environment may exceed that which...

show abstract

“…The measuring system was calibrated by the procedure of Young et al (1984). Heat production was calculated using the equation of Mclean (1972).…”

Section: Methodsmentioning

confidence: 99%

Effect of water restriction and environmental temperatures on metabolic rate and physiological parameters in sheep

Li¹,

Christopherson²,

Cosgrove³

2000

Can. J. Anim. Sci.

View full text Add to dashboard Cite

show abstract

“…The respiratory hoods, supported by individual stancheons, allowed normal access of the lambs to feed and water, and standing/lying activities were not restricted. This open-circuit system was calibrated with nitrogen as a zero oxygen reference (Young et al 1984), and the heat production was calculated from V O2 using the equation of McLean (1972). The difference between the metabolizable energy intake and heat production (metabolic rate) represented the energy balance of the animal (Bennett 1972).…”

Section: Metabolic Rate and Rectal Temperaturementioning

confidence: 99%

Metabolic and endocrine responses to cold and feed restriction in ruminants

Ekpe¹,

Christopherson²

2000

Can. J. Anim. Sci.

View full text Add to dashboard Cite

Ekpe, E. D. and Christopherson, R. J. 2000. Metabolic and endocrine responses to cold and feed restriction in ruminants. Can. J. Anim. Sci. 80: 87-95. Twenty-four wether lambs were assigned to different temperature and feeding levels to assess their metabolic and endocrine profiles and to test the hypothesis that energy conservation responses of sheep to feed restriction occur in warm but not cold environments. Lambs were kept in warm (W; 23 ± 2°C) or cold (C; 0 ± 2°C) environments and received either an ad libitum (A) or a restricted (1.35 × maintenance) (R) level of feed intake, thus creating four treatment groups (WA, WR, CA and CR). Average daily gain (ADG), feed intake, metabolic rates, rectal temperature, and plasma levels of insulin, thyroxine (T4), triiodothyronine (T3) and cortisol were recorded during three periods of 5 wk each. The ADG was lower (P < 0.001) in feed-restricted groups. Cold exposure reduced the ADG along with feed efficiency in the first period (P < 0.01). Metabolic rate was lowered by feed restriction (P < 0.01) in periods 1 and 3, but was increased by cold exposure in ad libitum-fed sheep during period 1 (P < 0.05). Both cold exposure and feed restriction lowered rectal temperature (P< 0.001). Plasma insulin concentration was lowered by feed restriction (P < 0.05) and was increased (P < 0.05) by cold exposure during periods 2 and 3. Plasma T3 concentration was reduced (P < 0.05) by feed restriction and was increased by cold exposure during periods 1 and 2. Plasma T4 level remained unaltered (P > 0.05) while plasma cortisol concentration was increased by both cold exposure and feed restriction (P < 0.01). The results indicate that lambs show metabolic and physiological responses to feed restriction, which conserve energy in a cold as well as a warm environment. Le gain quotidien moyen, l'ingéré alimentaire, les taux de thermogenèse, la tempéra-ture rectale et les niveaux plasmatiques d'insuline, de thyroxine (T4), de triiodothyronine (T3) et de cortisol étaient mesurés durant trois périodes de cinq semaines chacune. Le GQM était plus faible (P < 0,001) parmi les groupes rationnés. L'exposition au froid abaissait le GQM et l'efficacité alimentaire dans la première période seulement (P < 0,01). Le taux métabolique énergétique était diminué (P < 0,01) par le rationnement dans les périodes 1 et 3, mais était augmenté par l'exposition au froid des moutons nourris à satiété durant la première période (P < 0,05). Exposition au froid et alimentation restreinte provoquaient toutes deux une chute de la température rectale (P < 0,001). Les concentrations plasmatiques d'insuline et de T3 étaient abaissées (P < 0,05) par suite du rationnement, mais augmentées (P < 0,05) en ambiance froide durant les périodes 2 et 3 dans le cas de l'insuline et 1 et 2 dans celui de la T3. Les niveaux plasmatiques de T4 demeuraient inchangés (P > 0,05), tandis que ceux de cortisol augmentaient en réponse à l'exposition au froid et au rationnement (P < 0,01). Il ressort de ces observations que, exposés à une alimentat...

show abstract

“…Heat of combustion of oven-dried feed and feces samples, and oven-dried (60ºC, 48 h) urine were determined using an adiabatic calorimeter (Shimadzu CA-4PJ, Japan). Heat production (HP, kJ) was calculated by the equation, HP = 21.20 × O 2 -6.40 × CH 4 -5.99 × N, where O 2 and CH 4 represent volumes of oxygen consumed and methane produced (l), respectively, and N is the quantity of urinary nitrogen excreted (g) 13 .…”

Section: Introductionmentioning

confidence: 99%

Comparative Study on Energy and Nitrogen Metabolisms between Brahman Cattle and Swamp Buffalo Fed with Low Quality Diet

Kawashima

Sumamal²,

Pholsen³

et al. 2006

JARQ

View full text Add to dashboard Cite

A metabolism trial was conducted with four Brahman cattle and four swamp buffaloes fed with Ruzi grass hay (Brachiaria ruziziensis, 0.77% N). There was no significant difference in energy and nitrogen balances, and nutrient digestibilities between cattle and buffaloes. However, fasting heat production was significantly lower in buffaloes. Urinary excretion of allantoin tended to be lower in buffaloes than in cattle although there was no significant difference. Free fatty acid content in the blood serum during the fasting period was lower in buffaloes than in cattle although it was not different when the animals were fed. On the other hand, urea content in the blood serum during the fasting period was higher in buffaloes than in cattle.

show abstract

On the calculation of heat production from open-circuit calorimetric measurements

Cited by 127 publications

References 1 publication

Effect of water restriction and environmental temperatures on metabolic rate and physiological parameters in sheep

Effect of water restriction and environmental temperatures on metabolic rate and physiological parameters in sheep

Metabolic and endocrine responses to cold and feed restriction in ruminants

Comparative Study on Energy and Nitrogen Metabolisms between Brahman Cattle and Swamp Buffalo Fed with Low Quality Diet

Contact Info

Product

Resources

About