Chemische Analysen der Panseninhalte von Steinwild in Graubünden

Tataruch, Frieda; Onderscheka, K.

doi:10.1007/bf02239624

Cited by 4 publications

(3 citation statements)

References 8 publications

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“…Annual changes in the composition of the natural diet were determined from samples of the rumen content of free-living red deer culled during 1972-1998 in various parts of Austria and Switzerland throughout all seasons (average altitude of culling sites 1,072 m above sea level, range 458-2,000 m). Rumen content samples from 291 males and 333 females were analyzed for crude protein, crude fat, crude ash, crude fiber, and nitrogen free extract (NFE) by Weender analysis (67). From these results, seasonal changes of the gross energy content of ingested dry organic matter were calculated with rounded values of 23 kJ/g for protein, 40 kJ/g for fat, and 17 kJ/g for carbohydrates (51).…”

Section: Methodsmentioning

confidence: 99%

Nocturnal hypometabolism as an overwintering strategy of red deer (Cervus elaphus)

Arnold

Ruf

Reimoser

et al. 2004

American Journal of Physiology-Regulatory, Integrative and Comp

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126

143

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. Nocturnal hypometabolism as an overwintering strategy of red deer (Cervus elaphus). Am J Physiol Regul Integr Comp Physiol 286: R174-R181, 2004. First published September 11, 2003 10.1152/ajpregu.00593.2002Herbivores of temperate and arctic zones are confronted during winter with harsh climatic conditions and nutritional shortness. It is still not fully understood how large ungulates cope with this twofold challenge. We found that red deer, similar to many other northern ungulates, show large seasonal fluctuations of metabolic rate, as indicated by heart rate, with a 60% reduction at the winter nadir compared with the summer peak. A previously unknown mechanism of energy conservation, i.e., nocturnal hypometabolism associated with peripheral cooling, contributed significantly to lower energy expenditure during winter. Predominantly during late winter night and early morning hours, subcutaneous temperature could decrease substantially. Importantly, during these episodes of peripheral cooling, heart rate was not maintained at a constant level, as to be expected from classical models of thermoregulation in the thermoneutral zone, but continuously decreased with subcutaneous temperature, both during locomotor activity and at rest. This indicates that the circadian minimum of basal metabolic rate and of the set-point of body temperature regulation varied and dropped to particularly low levels during late winter. Our results suggest, together with accumulating evidence from other species, that reducing endogenous heat production is not restricted to hibernators and daily heterotherms but is a common and well-regulated physiological response of endothermic organisms to energetically challenging situations. Whether the temperature of all tissues is affected, or the body shell only, may simply be a result of the duration and degree of hypometabolism and its interaction with body size-dependent heat loss. hypometabolism; hypothermia; winter adaptation; body temperature regulation MANY UNGULATES ARE CAPABLE of withstanding long and cold winters with low food availability. Large body size, excellent fur insulation, and countercurrent heat exchange mechanisms contribute to minimize energy requirements under cold load. However, reduced heat loss alone can hardly explain the substantially lowered metabolic rate (MR) of northern ungulates and the apparently ubiquitous decrease of voluntary food intake during winter (4,13,18,28,35,37,42,44,59,63,72). The search for mechanism to explain reduced energy expenditure during winter has so far produced equivocal results. Studies on white-tailed deer [Odocoileus virginianus (66)], moose [Alces alces (56, 57)], roe deer [Capreolus capreolus (69)], and wapiti [Cervus elaphus nelsoni (49)] reported that animals had reduced MRs during winter. However, other studies failed to find any differences between summer and winter basal metabolic rate (BMR) and concluded that seasonal variations in MR were merely consequences of different activity levels and failures to measure animals within thei...

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Section: Methodsmentioning

confidence: 99%

Nocturnal hypometabolism as an overwintering strategy of red deer (Cervus elaphus)

Arnold

Ruf

Reimoser

et al. 2004

American Journal of Physiology-Regulatory, Integrative and Comp

Self Cite

126

143

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“…peak CI of ammonia production, mid-April to mid-May, with Figure 10). Figure 8 (colour online) Seasonal changes of phosphorus concentrations in the rumen content of four wild ruminant species and in the stomach content of the monogastric European brown hare (for methods, see Tataruch and Onderscheka, 1996). Plotted are monthly means with 95% CI.…”

Section: Stimulation Of Microbial Protein Biosynthesis By Phosphorus mentioning

confidence: 99%

“…Lines represent periodic fits to the data; horizontal bars indicate 95% CI of peak or trough location, respectively. Figure 9 (colour online) Seasonal changes of CP in the rumen content of free-living wild ruminants (for methods, see Tataruch and Onderscheka, 1996). Plotted are monthly means with 95% CI.…”

Section: Stimulation Of Microbial Protein Biosynthesis By Phosphorus mentioning

confidence: 99%

Review: Seasonal differences in the physiology of wild northern ruminants

Arnold

2020

Animal

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Ruminants living in seasonal environments face a two-fold challenge during winter. The energetic cost of maintaining a high body temperature is higher at lower ambient temperatures, and this is compounded by poor availability and quality of feed. Wild ruminants acclimatize to this energetic challenge by hypothermia, that is, reduced endogenous heat production and abandoning the maintenance of a high body temperature, particularly in peripheral body parts. Further but lesser contributions to lower energy expenditure during winter are reduced foraging activity; lower heat increment of feeding; and reduced maintenance cost of size-reduced organs. Altogether, metabolic rate, estimated by the continuous measurement of heart rate, during winter is downregulated to more than half of the summer level, as is voluntary food intake, even in animals fed ad libitum. The transformation from the summer into the thrifty winter phenotype is also evident in the physiology of digestion. Microbial protein synthesis is less facilitated by diminished phosphorus secretion into the shrunk rumen during winter. In line with this result, the concentration of ammonia, the end-product of protein digestion in the rumen, peaks in rumen liquid in spring, whereas the molar proportion of acetate, an indicator of fermentation of a diet rich in fiber, peaks in winter. In contrast to reduced stimulation of growth of ruminal microbes during winter, active transport of nutrients across the intestinal epithelium is increased, resulting in more efficient exploitation of the lower amount and quality of ingested winter feed. Nevertheless, the energy balance remains negative during winter. This is compensated by using fat reserves accumulated during summer, which become a major metabolic fuel during winter.

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Untersuchungen zur Kondition des Steinwildes (Capra i. ibex L.) in Graubünden

Tataruch

Onderscheka

1996

Zeitschrift für Jagdwissenschaft

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Chemische Analysen der Panseninhalte von Steinwild in Graubünden

Cited by 4 publications

References 8 publications

Nocturnal hypometabolism as an overwintering strategy of red deer (Cervus elaphus)

Nocturnal hypometabolism as an overwintering strategy of red deer (Cervus elaphus)

Review: Seasonal differences in the physiology of wild northern ruminants

Untersuchungen zur Kondition des Steinwildes (Capra i. ibex L.) in Graubünden

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