Seasonal adjustment of energy budget in a large wild mammal, the Przewalski horse (Equus ferus przewalskii) II. Energy expenditure

@article{Arnold2006SeasonalAO,
  title={Seasonal adjustment of energy budget in a large wild mammal, the Przewalski horse (Equus ferus przewalskii) II. Energy expenditure},
  author={Walter Arnold and Thomas Ruf and Regina Kuntz},
  journal={Journal of Experimental Biology},
  year={2006},
  volume={209},
  pages={4566 - 4573}
}
SUMMARY Many large mammals show pronounced seasonal fluctuations of metabolic rate (MR). It has been argued, based on studies in ruminants, that this variation merely results from different levels of locomotor activity (LA), and heat increment of feeding (HI). However, a recent study in red deer (Cervus elaphus) identified a previously unknown mechanism in ungulates - nocturnal hypometabolism - that contributed significantly to reduced energy expenditure, mainly during late winter. The relative… 
Adaptation strategies to seasonal changes in environmental conditions of a domesticated horse breed, the Shetland pony (Equus ferus caballus)
TLDR
The results show that Shetland ponies exhibit signs of a winter hypometabolism indicated by reduced heart rate and Ts, which seems to have maintained the capacity for seasonal adaptation to environmental conditions by seasonal fluctuations in their metabolic rate.
Thyroid hormones correlate with field metabolic rate in ponies, Equus ferus caballus
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Thyroid hormones and energy expenditure are correlated in a semi-free-living ungulate during winter and across both seasons, FMR, resting heart rate and locomotor activity were positively correlated with total T3 but negatively and more weakly correlated withtotal T4.
Seasonal changes in energy expenditure, body temperature and activity patterns in llamas (Lama glama)
TLDR
Llamas seem to have maintained the ability to reduce their energy expenditure and adjust their Tb under adverse environmental conditions as has been reported for some wild ungulates.
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TLDR
It is concluded that Shetland pony mares acclimatize to different climatic conditions by changing their metabolic rate, behaviour and some physiological parameters.
Hypometabolism and basking: the strategies of Alpine ibex to endure harsh over-wintering conditions
TLDR
The energetic benefits of basking can explain the strong residual seasonality of heart rate in Alpine ibex and hypometabolism and passive rewarming by basking may be of general importance as a strategy for non-hibernating mammals to survive winter in strongly seasonal habitats.
Atypical for northern ungulates, energy metabolism is lowest during summer in female wild boars (Sus scrofa)
TLDR
Wild boar females had peak heart rates early in the year, which likely indicates high costs of reproduction and a prerequisite for this early reproduction as well as for high energy metabolism over winter is the broad variety of food consumed by this species, i.e., the omnivorous lifestyle.
Quantifying energetic and fitness consequences of seasonal heterothermy in an Arctic ungulate
TLDR
It is shown that seasonal heterothermy can buffer the negative consequences of poor prewinter body condition or reduced winter food accessibility, leading to greater winter survival and spring energy reserves, and thus increased probability of future reproductive success.
Review: Seasonal differences in the physiology of wild northern ruminants.
  • W. Arnold
  • Medicine, Biology
    Animal : an international journal of animal bioscience
  • 2020
TLDR
The transformation from the summer into the thrifty winter phenotype is also evident in the physiology of digestion, where 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.
Seasonal Hypometabolism in Female Moose
How animals respond to a changing environment is a key question in ecological research. Animals living at higher latitudes are exposed to pronounced seasonal differences in both climate and in
Regulation of heart rate and rumen temperature in red deer: effects of season and food intake
TLDR
The hypothesis that a reduction in body temperature is a physiological mechanism employed even by large mammals, like red deer, to reduce their energy expenditure during periods of negative energy balance is supported.
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TLDR
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