| Records |
| Author |
Nicol, C.J.; Adachi, M.; Akiyama, T.E.; Gonzalez, F.J. |
Title  |
PPARgamma in endothelial cells influences high fat diet-induced hypertension |
Type |
Journal Article |
| Year |
2005 |
Publication |
American journal of hypertension : journal of the American Society of Hypertension |
Abbreviated Journal |
Am J Hypertens |
| Volume |
18 |
Issue |
4 Pt 1 |
Pages |
549-556 |
| Keywords |
Administration, Oral; Animals; Antihypertensive Agents/pharmacology; Blood Pressure/drug effects; Diabetes Mellitus, Type 2/physiopathology; Dietary Fats/*administration & dosage/pharmacology; Dose-Response Relationship, Drug; Endothelial Cells/*metabolism; Female; Heart Rate/drug effects; Hypertension/*etiology; Ligands; Male; Mice; Mice, Knockout; PPAR gamma/*metabolism; Sodium Chloride/administration & dosage/pharmacology; Thiazolidinediones/pharmacology |
| Abstract |
BACKGROUND: Peroxisome proliferator-activated receptor gamma (PPARgamma) ligands improve human hypertension. However, the mechanism and site of this effect remains unknown, confounded by PPARgamma expression in many cell types, including endothelial cells (ECs). METHODS: To evaluate the vascular role of PPARgamma we used a conditional null mouse model. Specific disruption of PPARgamma in ECs was created by crossing Tie2-Cre+ transgenic (T2T+) and PPARgamma-floxed (fl/fl) mice to generate PPARgamma (fl/fl)T2T+ (PPARgamma E-null) mice. Conscious 8- to 12-week-old congenic PPARgamma (fl/fl)Cre- (wild type) and PPARgamma E-null mice were examined for changes in systolic blood pressure (BP) and heart rate (HR), untreated, after 2 months of salt-loading (drinking water), and after treatment for 3 months with high fat (HF) diet alone or supplemented during the last 2 weeks with rosiglitazone (3 mg/kg/d). RESULTS: Untreated PPARgamma E-nulls were phenotypically indistinguishable from wild-type littermates. However, compared to similarly treated wild types, HF-treated PPARgamma E-nulls had significantly elevated systolic BP not seen after normal diet or salt-loading. Despite sex-dependent baseline differences, salt-loaded and HF-treated PPARgamma E-nulls of either sex had significantly elevated HR versus wild types. Interestingly, rosiglitazone improved serum insulin levels, but not HF diet-induced hypertension, in PPARgamma E-null mice. CONCLUSIONS: These results suggest that PPARgamma in ECs not only is an important regulator of hypertension and HR under stressed conditions mimicking those arising in type 2 diabetics, but also mediates the antihypertensive effects of rosiglitazone. These data add evidence supporting a beneficial role for PPARgamma-specific ligands in the treatment of hypertension, and suggest therapeutic strategies targeting ECs may prove useful. |
| Address |
Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA |
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
English |
Summary Language |
|
Original Title |
|
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0895-7061 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
PMID:15831367 |
Approved |
no |
| Call Number |
refbase @ user @ |
Serial |
69 |
| Permanent link to this record |
| |
|
| |
| Author |
Christensen, J.W.; Rundgren, M. |
| Title |
Predator odour per se does not frighten domestic horses |
Type |
Journal Article |
| Year |
2008 |
Publication |
Applied Animal Behaviour Science |
Abbreviated Journal |
Appl. Anim. Behav. Sci. |
| Volume |
112 |
Issue |
1-2 |
Pages |
136-145 |
| Keywords |
Horse; Predator odour; Behaviour; Heart rate; Fear |
| Abstract |
Horses frequently react nervously when passing animal production farms and other places with distinctive smells, leading riders to believe that horses are innately frightened by certain odours. In three experiments, we investigated how horses respond to (1) urine from wolves and lions, (2) blood from slaughtered conspecifics and fur-derived wolf odour, and (3) a sudden auditory stimulus in either presence or absence of fur-derived wolf odour. The experiments were carried out under standardised conditions using a total of 45 naive, 2-year-old horses. In the first two experiments we found that horses showed significant changes in behaviour (Experiments 1 and 2: increased sniffing; Experiment 2 only: increased vigilance, decreased eating, and more behavioural shifts), but no increase in heart rate compared to controls when exposed to predator odours and conspecific blood in a known test environment. However, the third experiment showed that exposure to a combination of wolf odour and a sudden stimulus (sound of a moving plastic bag) caused significantly increased heart rate responses and a tendency to a longer latency to resume feeding, compared to control horses exposed to the sudden stimulus without the wolf odour. The results indicate that predator odour per se does not frighten horses but it may cause an increased level of vigilance. The presence of predator odour may, however, cause an increased heart rate response if horses are presented to an additional fear-eliciting stimulus. This strategy may be adaptive in the wild where equids share habitats with their predators, and have to trade-off time and energy spent on anti-predation responses against time allocated to essential non-defensive activities. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Summary Language |
|
Original Title |
|
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
|
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
|
Approved |
no |
| Call Number |
Admin @ knut @ |
Serial |
4339 |
| Permanent link to this record |
| |
|
| |
| Author |
Waiblinger, S.; Menke, C.; Korff, J.; Bucher, A. |
| Title |
Previous handling and gentle interactions affect behaviour and heart rate of dairy cows during a veterinary procedure |
Type |
Journal Article |
| Year |
2004 |
Publication |
Applied Animal Behaviour Science |
Abbreviated Journal |
Appl. Anim. Behav. Sci. |
| Volume |
85 |
Issue |
1-2 |
Pages |
31-42 |
| Keywords |
Human-animal relationship; Cattle; Handling; Stress; Heart rate; Welfare |
| Abstract |
Veterinary and management procedures often are aversive to the animals, resulting in physiological and behavioural stress reactions, which increase the risk of accidents and might lower performance. We investigated the effects of previous positive handling and of gentle interactions during the procedure on behaviour and heart rate in dairy cows during rectal palpation with sham insemination. Twenty cows were allocated randomly into two groups of 10 animals: handling, received additional positive handling over a period of four weeks by one person (handler); control, only routine handling by different caretakers. The week after the handling period, tests lasting 9 min, including 4 min rectal palpation, were carried out with each animal on four successive days in four situations in a balanced order: cow is alone during the test, with the handler, with an usual caretaker, or with an unknown person. Behaviour and heart rate were recorded. Previously handled animals had lower heart rate during tests (P<=0.05, n=19), kicked less when alone (P<=0.05, n=19) and tended to show less restless behaviour (P<=0.1, n=19). Cows were further calmed by gentle interactions during the test, but people differed remarkably. Cows showed less restless behaviour when gentled by the handler, both in the 4 min of rectal palpation and in the 9 min test period (each: P<=0.001, n=19). No significant stress reducing effect was found for the other two persons. In conclusion, stress reactions of cows during rectal palpation/insemination can be reduced by previous positive handling as well as by a person providing positive, gentle interactions during the procedure. The results underline the importance of positive, gentle interactions with the animals to enhance animal welfare and reduce the risk of accidents. They also show that people differ in the success to calm down the animals in aversive situations and indicate the need to investigate the characteristics responsible for the differences and identify the preconditions for a stress reducing effect in future research. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Summary Language |
|
Original Title |
|
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
|
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
|
Approved |
no |
| Call Number |
Equine Behaviour @ team @ |
Serial |
4397 |
| Permanent link to this record |
| |
|
| |
| Author |
A. Lanata; A. Guidi; G. Valenza; P. Baragli; E. P. Scilingo |
| Title |
Quantitative heartbeat coupling measures in human-horse interaction |
Type |
Conference Article |
| Year |
2016 |
Publication |
2016 38th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) |
Abbreviated Journal |
2016 38th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (E |
| Volume |
|
Issue |
|
Pages |
2696-2699 |
| Keywords |
electrocardiography; medical signal processing; signal classification; time series; Dtw; Hrv; Mpc; Msc; complex biological systems; dynamic time warping; grooming; heart rate variability time series; heartbeat dynamics; human-horse dynamic interaction; magnitude squared coherence; magnitude-phase coupling; mean phase coherence; nearest mean classifier; quantitative heartbeat coupling; real human-animal interaction; time duration; visual-olfactory interaction; Coherence; Couplings; Electrocardiography; Heart rate variability; Horses; Protocols; Time series analysis |
| Abstract |
Abstract— We present a study focused on a quantitative estimation of a human-horse dynamic interaction. A set of measures based on magnitude and phase coupling between heartbeat dynamics of both humans and horses in three different conditions is reported: no interaction, visual/olfactory interaction and grooming. Specifically, Magnitude Squared Coherence (MSC), Mean Phase Coherence (MPC) and Dynamic Time Warping (DTW) have been used as estimators of the amount of coupling between human and horse through the analysis of their heart rate variability (HRV) time series in a group of eleven human subjects, and one horse. The rationale behind this study is that the interaction of two complex biological systems go towards a coupling process whose dynamical evolution is modulated by the kind and time duration of the interaction itself. We achieved a congruent and consistent
statistical significant difference for all of the three indices. Moreover, a Nearest Mean Classifier was able to recognize the three classes of interaction with an accuracy greater than 70%. Although preliminary, these encouraging results allow a discrimination of three distinct phases in a real human-animal interaction opening to the characterization of the empirically proven relationship between human and horse. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Summary Language |
|
Original Title |
|
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
2016 38th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (E |
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
1557-170x |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
|
Approved |
no |
| Call Number |
Equine Behaviour @ team @ |
Serial |
6175 |
| Permanent link to this record |
| |
|
| |
| Author |
Marlin, D.J.; Schroter, R.C.; White, S.L.; Maykuth, P.; Matthesen, G.; Mills, P.C.; Waran, N.; Harris, P. |
| Title |
Recovery from transport and acclimatisation of competition horses in a hot humid environment |
Type |
Journal Article |
| Year |
2001 |
Publication |
Equine Veterinary Journal |
Abbreviated Journal |
Equine Vet J |
| Volume |
33 |
Issue |
4 |
Pages |
371-379 |
| Keywords |
Acclimatization/*physiology; Animals; Body Temperature; Body Weight; Breeding; Feeding Behavior; Female; Heart Rate; Heat; Heat Stroke/prevention & control/veterinary; Horse Diseases/prevention & control; Horses/*physiology; Humidity; Male; Respiration; Sports; *Transportation; Tropical Climate |
| Abstract |
The aims of the present field-based study were to investigate changes in fit horses undergoing acclimatisation to a hot humid environment and to provide data on which to base recommendations for safe transport and acclimatisation. Six horses (age 7-12 years) were flown from Europe to Atlanta and underwent a 16 day period of acclimatisation. Exercise conditions during acclimatisation (wet bulb globe temperature index 27.6+/-0.0 [mean +/- s.e.]) were more thermally stressful compared with the European climate from which the horses had come (22.0+/-1.8, P<0.001). Following the flight, weight loss was 4.1+/-0.8% bodyweight and took around 7 days to recover. Water intake during the day was significantly increased (P<0.05) compared with night during acclimatisation. Daily mean exercise duration was 72+/-12 min and the majority of work was performed with a heart rate below 120 beats/min. Respiratory rate (fR) was increased (P<0.05) throughout acclimatisation compared with in Europe, but resting morning (AM) and evening (PM) rectal temperature (TREC), heart rate (fC) and plasma volume were unchanged. White blood cell (WBC) count was significantly increased at AM compared with in Europe on Days 4 and 10 of acclimatisation (P<0.01), but was not different by Day 16. In conclusion, horses exposed to hot humid environmental conditions without prior acclimatisation are able to accommodate these stresses and, with appropriate management, remain fit and clinically healthy, without significant risk of heat illness or heat-related disorders, provided they are allowed sufficient time to recover from transport, acclimatisation is undertaken gradually and they are monitored appropriately. |
| Address |
Centre for Equine Studies, Animal Health Trust, Newmarket, Suffolk, UK |
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
English |
Summary Language |
|
Original Title |
|
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0425-1644 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
PMID:11469770 |
Approved |
no |
| Call Number |
refbase @ user @ |
Serial |
1917 |
| Permanent link to this record |
| |
|
| |
| Author |
Trim, C.M.; Moore, J.N.; Clark, E.S. |
| Title |
Renal effects of dopamine infusion in conscious horses |
Type |
Journal Article |
| Year |
1989 |
Publication |
Equine veterinary journal. Supplement |
Abbreviated Journal |
Equine Vet J Suppl |
| Volume |
|
Issue |
7 |
Pages |
124-128 |
| Keywords |
Animals; Blood Pressure/drug effects/physiology; Consciousness/*physiology; Creatinine/blood; Dopamine/administration & dosage/*pharmacology; Dose-Response Relationship, Drug; Female; Heart Rate/drug effects/physiology; Horses/*physiology; Infusions, Intravenous/veterinary; Kidney/blood supply/*drug effects/physiology; Osmolar Concentration; Potassium/blood; Random Allocation; Regional Blood Flow/drug effects/physiology; Renal Artery/drug effects/physiology/ultrasonography; Sodium/blood; Time Factors; Ultrasonography/methods/veterinary; Urination/physiology |
| Abstract |
An ultrasonic flow probe was implanted around a branch of the left renal artery in five horses. The effects of dopamine were studied in the unsedated horses 10 days after surgery. Three experiments, separated by at least two days, were performed in random order on each horse. In two experiments, dopamine was infused intravenously for 60 mins at either 2.5 and 5.0 micrograms/kg bodyweight (bwt)/min. Saline was infused for 60 mins before and after each infusion, and for 180 mins in the third experiment as a control. Renal blood flow increased during administration of dopamine at both dose rates (P = 0.0001). Urine volume increased (P = 0.055), and osmolality decreased (P < 0.05), with infusion of dopamine at 5.0 micrograms/kg bwt/min. Arterial blood pressure and heart rate were not significantly affected. Fractional excretions of sodium and potassium were not significantly changed with dopamine infusion. The higher dopamine dose rate was accompanied by dysrhythmias in some horses. |
| Address |
Department of Large Animal Medicine, College of Veterinary Medicine, University of Georgia, Athens 30602, USA |
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
English |
Summary Language |
|
Original Title |
|
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
|
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
PMID:9118094 |
Approved |
no |
| Call Number |
refbase @ user @ |
Serial |
99 |
| Permanent link to this record |
| |
|
| |
| Author |
Visser, E.K.; Van Reenen, C.G.; Rundgren, M.; Zetterqvist, M.; Morgan, K.; Blokhuis, H.J. |
| Title |
Responses of horses in behavioural tests correlate with temperament assessed by riders |
Type |
Journal Article |
| Year |
2003 |
Publication |
Equine Veterinary Journal |
Abbreviated Journal |
Equine Vet J |
| Volume |
35 |
Issue |
2 |
Pages |
176-183 |
| Keywords |
Adult; Animals; *Behavior, Animal/physiology; Data Interpretation, Statistical; Female; *Handling (Psychology); Heart Rate/*physiology; Horses/physiology/*psychology; Humans; Male; Personality; Temperament/*physiology |
| Abstract |
REASONS FOR PERFORMING STUDY: Behavioural tests as well as observers' ratings have been used to study horses' temperament. However, the relationship between the ratings and the responses in behavioural tests has not yet been studied in detail. OBJECTIVES: The aim of the present study was to examine this relationship between ratings and responses. METHODS: Eighteen mature Swedish Warmblood horses were subjected to 2 behavioural tests, one relating to novelty (novel object test) and one to handling (handling test). Subsequently, 16 of these horses were ridden by 16 equally experienced students, having no former experience with the horses. Immediately after each ride, the students scored the horse for 10 temperamental traits using a line rating method. RESULTS: It was shown that for each temperamental trait all 16 riders agreed on the ranking of the horses (0.212<W<0.505, P < 0.001). CONCLUSIONS: Correlations between behavioural and heart rate variables in the behavioural tests revealed that horses with a high level of locomotion or much restlessness behaviour exhibited high mean heart rate and low heart rate variability. In particular, heart rate variables in the behavioural tests were found to correlate with riders' rating scores. Furthermore, the underlying components of the handling test, retrieved with a principal component analysis (PCA) correlated with riders' rating scores while the underlying components of the novel object test did not. POTENTIAL CLINICAL RELEVANCE: It is concluded that it is possible for a large panel of assessors to agree upon a horse's temperament and that objective measures from behavioural tests correlate significantly with temperamental traits assessed by a panel of assessors. |
| Address |
Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, PO Box 80.163, NL-3508 TD Utrecht, The Netherlands |
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
English |
Summary Language |
|
Original Title |
|
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0425-1644 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
PMID:12638795 |
Approved |
no |
| Call Number |
|
Serial |
1906 |
| Permanent link to this record |
| |
|
| |
| Author |
Christensen, J.W.; Keeling, L.J.; Nielsen, B.L. |
| Title |
Responses of horses to novel visual, olfactory and auditory stimuli |
Type |
Journal Article |
| Year |
2005 |
Publication |
Applied Animal Behaviour Science |
Abbreviated Journal |
Appl. Anim. Behav. Sci. |
| Volume |
93 |
Issue |
1-2 |
Pages |
53-65 |
| Keywords |
Horses; Novelty responses; Fear; Behaviour; Heart rate |
| Abstract |
Responses of horses towards fear-eliciting stimuli can have important consequences for both human and horse safety. This experiment was designed to investigate behavioural and heart rate (HR) responses of horses to novel visual, auditory and olfactory stimuli. Twenty-four 2-year-old, previously unhandled, stallions were habituated to receive a food reward from a container in a test arena. Each horse was exposed to three 2 min tests in a balanced design where in addition to the feed container, either a traffic cone (visual test), white noise (auditory test) or eucalyptus oil applied to the inside of the container (olfactory test) were used as the novel stimuli. Compared to the control, less time was spent eating during all tests. There was no difference in locomotion activity in the different test situations, but presentation of the novel visual and auditory stimuli elicited significantly increased HR responses in the horses, compared to their response to the arena without novel stimuli (control), whereas there was no increase in HR response to the olfactory stimulus. However, during the olfactory test, the horses had an increased number of eating bouts and became more vigilant towards their surroundings, whereas during the visual and auditory tests, more time was spent alert towards the stimulus. The horses also took significantly more steps backwards in response to the auditory test. The heart rate responses correlated between tests and reflect a non-differentiated activation of the sympathetic nervous system, while the behavioural responses were linked to the type of stimulus. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Summary Language |
|
Original Title |
|
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
|
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
|
Approved |
no |
| Call Number |
Equine Behaviour @ team @ |
Serial |
2256 |
| Permanent link to this record |
| |
|
| |
| Author |
Christensen, J.W.; Munk, R.; Hawson, L.; Palme, R.; Larsen, T.; Egenvall, A.; König von Borstel, U.U.; Rørvang, M.V. |
| Title |
Rider effects on horses' conflict behaviour, rein tension, physiological measures and rideability scores |
Type |
Journal Article |
| Year |
2021 |
Publication |
Applied Animal Behaviour Science |
Abbreviated Journal |
Appl. Anim. Behav. Sci. |
| Volume |
234 |
Issue |
|
Pages |
105184 |
| Keywords |
Equitation science; Heart rate; Horse riding; Sport horse; Temperament; Training cues |
| Abstract |
Many breeding organisations include a subjective scoring of rideability by a professional rider into their evaluation of sports horses, but the consistency and reliability of the scoring system is debateable. The aim of this study was to investigate (i) whether professional riders agree in their scoring of rideability, and (ii) whether rideability scores are affected by rein tension, horse conflict behaviour, heart rate, and salivary cortisol, and (iii) whether riders induce different levels of conflict behaviour and physiological responses in the horses. Ten professional, female riders each rode 10 dressage horses (level M German scale; n = 100 combinations) through a standardised dressage test (10 min warm-up followed by a 4-min test) and subsequently scored the horses for rideability on the official 1-10 scale (1 = poor to 10 = excellent) from the Danish Riding Federation. Rein tension, horse heart rate, saliva cortisol and conflict behaviour were measured for each rider-horse pair. The riders were inconsistent in their scoring of rideability to the individual horses, e.g. scores for one of the horses ranged from 1 to 8. There was a significant effect of rider (P = 0.003) and the frequency of conflict behaviour (undesired head movements: P < 0.001, breaking the gait: P = 0.013, and other evasive behaviour: P = 0.032) on rideability scores, i.e. the more conflict behaviour the lower the score. There was no significant effect of rein tension and the physiological measures on rideability scores. However, there was a significant effect of rider on rein tension, horses' heart rate and increases in saliva cortisol concentrations and a tendency for some types of conflict behaviour, suggesting that some riders induced more discomfort in the horses. Future studies could help shed light on which elements of riding style are particularly important for sports horse welfare. In conclusion, this study found a large variation in rideability scores assigned to ten sports horses by ten professional riders. Rideability scores were dependent on the level of horse conflict behaviour, but not rein tension and physiological measures. Further studies are needed to improve the objectivity, consistency and reliability of rideability assessment of sports horses. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Summary Language |
|
Original Title |
|
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0168-1591 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
|
Approved |
no |
| Call Number |
Equine Behaviour @ team @ |
Serial |
6696 |
| Permanent link to this record |
| |
|
| |
| Author |
Arnold, W.; Ruf, T.; Kuntz, R. |
| Title |
Seasonal adjustment of energy budget in a large wild mammal, the Przewalski horse (Equus ferus przewalskii) II. Energy expenditure |
Type |
Journal Article |
| Year |
2006 |
Publication |
The Journal of experimental biology |
Abbreviated Journal |
J Exp Biol |
| Volume |
209 |
Issue |
Pt 22 |
Pages |
4566-4573 |
| Keywords |
Animals; Animals, Wild/*physiology; Body Temperature; Body Temperature Regulation; Eating; *Energy Metabolism; Female; Heart Rate; Horses/*physiology; Male; Motor Activity; Pregnancy; Reproduction; *Seasons |
| Abstract |
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 contribution of these different mechanisms to seasonal adjustments of MR is still unknown, however. Therefore, in the study presented here we quantified for the first time the independent contribution of thermoregulation, LA and HI to heart rate (f(H)) as a measure of MR in a free-roaming large ungulate, the Przewalski horse or Takhi (Equus ferus przewalskii Poljakow). f(H) varied periodically throughout the year with a twofold increase from a mean of 44 beats min(-1) during December and January to a spring peak of 89 beats min(-1) at the beginning of May. LA increased from 23% per day during December and January to a mean level of 53% per day during May, and declined again thereafter. Daily mean subcutaneous body temperature (T(s)) declined continuously during winter and reached a nadir at the beginning of April (annual range was 5.8 degrees C), well after the annual low of air temperature and LA. Lower T(s) during winter contributed considerably to the reduction in f(H). In addition to thermoregulation, f(H) was affected by reproduction, LA, HI and unexplained seasonal variation, presumably reflecting to some degree changes in organ mass. The observed phase relations of seasonal changes indicate that energy expenditure was not a consequence of energy uptake but is under endogenous control, preparing the organism well in advance of seasonal energetic demands. |
| Address |
Research Institute of Wildlife Ecology, University of Veterinary Medicine, Vienna, Savoyenstrasse 1, 1160 Vienna, Austria. walter.arnold@vu-wien.ac.at |
| Corporate Author |
|
Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
English |
Summary Language |
|
Original Title |
|
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0022-0949 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
PMID:17079726 |
Approved |
no |
| Call Number |
|
Serial |
1782 |
| Permanent link to this record |
