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Author Kuntz, R.; Kubalek, C.; Ruf, T.; Tataruch, F.; Arnold, W. url  doi
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  Title Seasonal adjustment of energy budget in a large wild mammal, the Przewalski horse (Equus ferus przewalskii) I. Energy intake Type Journal Article
  Year 2006 Publication The Journal of experimental biology Abbreviated Journal J Exp Biol  
  Volume 209 Issue 22 Pages 4557-4565  
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  Abstract Large ruminants respond to changing plant phenology during winter by decreasing voluntary food intake, increasing gut passage time and utilizing body fat reserves. It is uncertain, however, how other large mammals with a non-ruminant digestive physiology cope with winter forage conditions. Therefore, we investigated seasonality of energy intake in a large herbivorous wild mammal, the Przewalski horse (Equus ferus przewalskii). Throughout all seasons we used the n-alkane method to measure daily dry matter intake (DMI), diet composition and digestion, and determined an index of gut passage time in horses living under close to natural conditions. DMI correlated positively with its content of crude protein and nitrogen-free extract. Independent of these effects, DMI further varied seasonally with a peak in autumn and a nadir in late winter. Fluctuations of DMI corresponded to the annual change in body condition, which decreased during winter while energy reserves were depleted, and increased during the fattening period. Gut passage time varied in the course of the year and was longer during winter when the diet was high in crude fibre. Nevertheless, changes in gut passage time occurred rather independently of changes in forage composition and DMI, suggesting endogenous control for timely adaption of the digestive strategy to meet predictable changes in forage quality.  
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  Notes 10.1242/jeb.02535 Approved no  
  Call Number Equine Behaviour @ team @ Serial (up) 4729  
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Author Brinkmann, L.; Gerken, M.; Hambly, C.; Speakman, J.R.; Riek, A. url  doi
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  Title Saving energy during hard times: Energetic adaptations of Shetland pony mares Type Journal Article
  Year 2014 Publication The Journal of Experimental Biology Abbreviated Journal J. Exp. Biol.  
  Volume 217 Issue Pages 4320-4327  
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  Abstract Recent results suggest that wild Northern herbivores reduce their metabolism during times of low ambient temperatures and food shortage in order to reduce their energetic needs. It is however not known if domesticated animals are also able to reduce their energy expenditure. We exposed ten Shetland pony mares to different environmental conditions (summer and winter) and to two food quantities (60 and 100% of maintenance energy requirement, respectively) during low winter temperatures to examine energetic and behavioural responses. In summer ponies showed a considerably higher field metabolic rate (FMR) (63.4±15.0 MJ d-1) compared to restrictively fed and control animals in winter (24.6±7.8 MJ d-1 and 15.0±1.1 MJ d-1, respectively). During summer conditions locomotor activity, resting heart rates and total water turnover were considerably elevated (P<0.001) compared to winter. Restrictively fed animals (N=5) compensated for the decreased energy supply by reducing their FMR by 26% compared to control animals (N=5). Furthermore, resting heart rate, body mass and body condition score were lower (29.2±2.7 beats min-1; 140±22 kg; 3.0±1.0 points) than in control animals (36.8±41 beats min-1; 165 ±31 kg; 4.4±0.7 points; P<0.05). While the observed behaviour did not change, nocturnal hypothermia was elevated. We conclude that ponies acclimatize to different climatic conditions by changing their metabolic rate, behaviour and some physiological parameters. When exposed to energy challenges, ponies, like wild herbivores, exhibited hypometabolism and nocturnal hypothermia.  
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  Notes 10.1242/jeb.111815 Approved no  
  Call Number Equine Behaviour @ team @ Serial (up) 5836  
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