Records |
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 |
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English |
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0022-0949 |
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PMID:17079726 |
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no |
Call Number |
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1782 |
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Author |
Pritchard, J.C.; Barr, A.R.S.; Whay, H.R. |
Title |
Validity of a behavioural measure of heat stress and a skin tent test for dehydration in working horses and donkeys |
Type |
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Year |
2006 |
Publication |
Equine veterinary journal |
Abbreviated Journal |
Equine Vet J |
Volume |
38 |
Issue |
5 |
Pages |
433-438 |
Keywords |
Age Factors; Animal Welfare; Animals; Behavior, Animal/physiology; Body Temperature/*physiology; Body Weight/physiology; Case-Control Studies; Dehydration/diagnosis/pathology/*veterinary; Drinking; *Equidae; Female; Heat Stress Disorders/diagnosis/physiopathology/*veterinary; Horse Diseases/*diagnosis/pathology; Horses; Hypovolemia/diagnosis/physiopathology/veterinary; Male; Osmolar Concentration; Pakistan; Respiration; Skin/*pathology; Species Specificity; Work |
Abstract |
REASONS FOR PERFORMING STUDY: Dehydration and heat stress are serious welfare issues for equids working in developing countries. There is a lack of any standardised method or validated interpretation of the skin tent test in horses and donkeys. Owners of dehydrated and heat-stressed animals often depend on veterinary examination for identification of these conditions, leading to delays in treatment and unnecessary reliance on external sources to effect welfare improvement. OBJECTIVES: To validate a standardised skin tent test for dehydration and a behavioural measure of heat stress in working equids; and to examine the effect of heat stress and dehydration on tripping and staggering behaviour. METHODS: The study was carried out on 130 working horses and donkeys in Pakistan. Associations between skin tent and blood parameters (packed cell volume [PCV], serum total protein [TP], serum osmolality), clinical parameters, resting and drinking behaviour were examined. Heat stress behaviour (increased respiratory rate and depth, head nodding, flared nostrils, apathy) was observed in conjunction with rectal temperature. Tripping and staggering were assessed using a simple obstacle course. RESULTS: In both species, heat stress behaviour was significantly associated with increased rectal temperature (P<0.001). A positive skin tent test was not significantly associated with PCV or TP, although in donkeys it was significantly associated with lower serum osmolality (P<0.001). More animals age >15 years had a positive skin tent than those in younger age groups (P = 0.037). Very thin horses were more likely to have a positive skin tent than those in thin or moderate condition (P = 0.028). There was no significant correlation between skin tent and tripping or staggering in either species. CONCLUSIONS AND POTENTIAL RELEVANCE: Heat stress behaviour is related to increased body temperature in working horses and donkeys. Owners may use this to make judgements regarding rest and cooling, precluding the need to seek veterinary attention. The skin tent test for dehydration used in this study did not show a significant relationship with PCV or TP. However, the use of blood parameters to validate the skin tent test may be confounded by anaemia, hypoproteinaemia or electrolyte depletion. Alternative methods are needed to confirm or refute the validity of the skin tent test in working equids. |
Address |
Department of Clinical Veterinary Science, University of Bristol, Langford, UK |
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0425-1644 |
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PMID:16986604 |
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no |
Call Number |
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Serial |
1784 |
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Author |
Kurvers, C.M.H.C.; van Weeren, P.R.; Rogers, C.W.; van Dierendonck, M.C. |
Title |
Quantification of spontaneous locomotion activity in foals kept in pastures under various management conditions |
Type |
Journal Article |
Year |
2006 |
Publication |
American journal of veterinary research |
Abbreviated Journal |
Am J Vet Res |
Volume |
67 |
Issue |
7 |
Pages |
1212-1217 |
Keywords |
Aging; Animal Husbandry; Animals; Female; Horses/*physiology; Male; Motor Activity/*physiology; Sex Characteristics |
Abstract |
OBJECTIVE: To describe spontaneous locomotion activity of foals kept under various management conditions and assess the suitability of global positioning system (GPS) technology for recording foal activity. Animals-59 foals. PROCEDURES: During the foals' first 4 months of life, 921 observation periods (15 minutes each) were collected and analyzed for locomotion activities. The GPS system was evaluated by simultaneously carrying out field observations with a handheld computer. RESULTS: Foals spent 0.5% of total observed time cantering, 0.2% trotting, 10.7% walking, 32.0% grazing, 34.8% standing, and 21.6% lying down. Total observed daytime workload (velocity x distance) in the first month was approximately twice that in the following months. Locomotion activity decreased with increasing age. Colts had more activity than fillies in certain periods, and foals that were stabled for some portion of the day had compensatory locomotion activity, which was probably insufficient to reach the level of foals kept continually outside. The GPS recordings and handheld-computer observations were strongly correlated for canter, trot, and walk and moderately correlated for standing and lying. Correlation for grazing was low. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that domestically managed foals, when kept 24 h/d at pasture, will exercise at a level comparable with feral foals. High workload during the first month of life might be important for conditioning the musculoskeletal system. The GPS technique accurately quantified canter, trot, and walk activities; less accurately indexed resting; and was unsuitable for grazing because of the wide array of velocities used while foraging. |
Address |
Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, The Netherlands |
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0002-9645 |
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PMID:16817745 |
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no |
Call Number |
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Serial |
1786 |
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Author |
Staniar, W.B.; Kronfeld, D.S.; Hoffman, R.M.; Wilson, J.A.; Harris, P.A. |
Title |
Weight prediction from linear measures of growing Thoroughbreds |
Type |
Journal Article |
Year |
2004 |
Publication |
Equine veterinary journal |
Abbreviated Journal |
Equine Vet J |
Volume |
36 |
Issue |
2 |
Pages |
149-154 |
Keywords |
Animal Nutrition Physiology; Animals; Biometry; Body Weight/*physiology; Female; Horses/*anatomy & histology/*growth & development; Male; Mathematics; Predictive Value of Tests; Reproducibility of Results; Sensitivity and Specificity |
Abstract |
REASON FOR PERFORMING STUDY: Monitoring weight of foals is a useful management practice to aid in maximising athletic potential while minimising risks associated with deviations from normal growth. OBJECTIVE: To develop predictive equations for weight, based on linear measurements of growing Thoroughbreds (TBs). METHODS: Morphometric equations predicting weight from measurements of the trunk and legs were developed from data of 153 foals. The accuracy, precision and bias of the best fitting equation were compared to published equations using a naive data set of 22 foals. RESULTS: Accuracy and precision were maximised with a broken line relating calculated volumes (V(t + l)) to measured weights. Use of the broken line is a 2 step process. V(t + l) is calculated from linear measures (m) of girth (G), carpus circumference (C), and length of body (B) and left forelimb (F). V(t + I) = ([G2 x B] + 4[C2 x F]) 4pi. If V(t + l) < 0.27 m3, weight is estimated: Weight (kg) = V(t + l) x 1093. If V(t + l) > or = 0.27 m3: Weight (kg) = V(t + l) x 984 + 24. The broken line was more accurate and precise than 3 published equations predicting the weight of young TBs. CONCLUSIONS: Estimation of weight using morphometric equations requires attention to temporal changes in body shape and density; hence, a broken line is needed. Including calculated leg volume in the broken line model is another contributing factor to improvement in predictive capability. POTENTIAL RELEVANCE: The broken line maximises its value to equine professionals through its accuracy, precision and convenience. |
Address |
Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061-0306, USA |
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0425-1644 |
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PMID:15038438 |
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no |
Call Number |
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Serial |
1806 |
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Author |
Jansen, W.L.; van Alphen, M.; Berghout, M.; Everts, H.; Beynen, A.C. |
Title |
An approach to assessment of the efficiency of dietary energy utilization by horses and ponies kept at riding schools |
Type |
Journal Article |
Year |
2001 |
Publication |
The Veterinary quarterly |
Abbreviated Journal |
Vet Q |
Volume |
23 |
Issue |
4 |
Pages |
195-198 |
Keywords |
*Animal Feed; Animal Husbandry; Animals; Body Weight; Dietary Fats; Dietary Fiber; *Energy Intake; *Energy Metabolism; Female; Horses/*physiology; Male |
Abstract |
The ratio of calculated net energy intake (NEi) to calculate net energy requirement (NEr) might serve as an indicator of the efficiency of dietary energy utilization. The ratio was determined for 93 horses and ponies from 10 riding schools. For each animal with an assumed constant body weight, energy intake and energy requirements were assessed. On average, the estimated NEi was 14% greater than NEr. There was a significant, negative association between crude fibre intake and the NEi: NEr ratio. Earlier work indicated that extra fat intake may lead to over estimation of the calculated energy value of the ration due to changes in macronutrient digestibility. Dietary fat concentration was found to range from 32 to 52 g/kg dry matter (5 to 6 g/MJ net energy), but on the basis of digestibility trials this range in fat concentration is too small to significantly influence the NEi: NEr ratio. This study shows that assessment of the efficiency of dietary energy utilization under normal conditions, on the basis of the NEi: NEr ratio is fraught with uncertainty. |
Address |
Department of Nutrition, Faculty of Veterinary, Medicine, Utrecht University, The Netherlands |
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ISSN |
0165-2176 |
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Notes |
PMID:11765239 |
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no |
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Serial |
1807 |
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Author |
Carroll, C.L.; Huntington, P.J. |
Title |
Body condition scoring and weight estimation of horses |
Type |
Journal Article |
Year |
1988 |
Publication |
Equine veterinary journal |
Abbreviated Journal |
Equine Vet J |
Volume |
20 |
Issue |
1 |
Pages |
41-45 |
Keywords |
Animals; Biometry; *Body Weight; Female; Horses/*anatomy & histology; Male; Physical Examination/*veterinary |
Abstract |
Three hundred and seventy two horses of varying breeds, height and fatness were weighed and measured for height at the withers. They were assessed for condition score by adaptation of a previously published method. The heart girth and length of 281 of the horses were also measured. Weight of horses was highly correlated (P less than 0.001) with height (r2 = 0.62), condition score (r2 = 0.22) and girth2 x length (r2 = 0.90). Nomograms were constructed to predict weight from height and condition score, and girth and length measurements. Weight can also be accurately estimated from the formula: (formula, see text) The average value of 'Y' in this experiment was 11900 and this estimated weight with more accuracy than some previously published values of 'Y'. Racing Thoroughbred horses were found to be significantly lighter than non-racing Thoroughbreds of the same height and condition score. The method of assessment of condition score was shown to be repeatable between different operators with varying degrees of experience. |
Address |
Department of Agriculture and Rural Affairs, Attwood Veterinary Research Laboratory, Westmeadows, Victoria, Australia |
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0425-1644 |
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PMID:3366105 |
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no |
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Serial |
1808 |
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Author |
McComb, K.; Clutton-Brock, T. |
Title |
Is mate choice copying or aggregation responsible for skewed distributions of females on leks? |
Type |
Journal Article |
Year |
1994 |
Publication |
Proceedings. Biological sciences / The Royal Society |
Abbreviated Journal |
Proc Biol Sci |
Volume |
255 |
Issue |
1342 |
Pages |
13-19 |
Keywords |
Animals; Deer/*physiology; Estrus/physiology; Female; Male; Phenotype; Sexual Behavior, Animal/*physiology; Territoriality |
Abstract |
In several lek-breeding populations of birds and mammals, females arriving on leks tend to join males that already have females in their territories. This might occur either because females have an evolved preference for mating with males that are attractive to other females, or because they join groups of other females to obtain greater safety from predation or dangerous harassment by males. We have previously used controlled experiments to show that oestrous fallow deer females join males with established harems because they are attracted to female groups rather than to the males themselves. Here we demonstrate that the preference for males with females over males without females is specific to oestrous females and weak or absent in anoestrous ones, and that it is not associated with a preference for mating with males that have previously been seen to mate with other females. Furthermore, oestrous females given the choice between males that do not already have females with them show no significant preference for antlered over deantlered males or for older males over younger ones. We conclude that female attraction to other females on the lek is likely to be an adaptation to avoiding harassment in mixed-sex herds. In this situation, a male's ability to maintain the cohesion of his harem may be the principal cause of variation in mating success between males. |
Address |
Department of Zoology, University of Cambridge, U.K |
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0962-8452 |
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PMID:8153135 |
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no |
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1823 |
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Author |
Hill, S.E.; Ryan, M.J. |
Title |
The role of model female quality in the mate choice copying behaviour of sailfin mollies |
Type |
Journal Article |
Year |
2006 |
Publication |
Biology letters |
Abbreviated Journal |
Biol Lett |
Volume |
2 |
Issue |
2 |
Pages |
203-205 |
Keywords |
Animals; *Choice Behavior; Female; Male; *Mating Preference, Animal; Poecilia/*physiology |
Abstract |
Female mate choice copying is a socially mediated mate choice behaviour, in which a male's attractiveness to females increases if he was previously chosen by another female as a mate. Although copying has been demonstrated in numerous species, little is known about the specific benefits it confers to copying females. Here we demonstrate that the mate choice behaviour of female sailfin mollies (Poecilia latipinna) is influenced by the phenotypic quality of model females with whom males are observed consorting. Test females choosing between two males of similar body length were found to significantly increase time spent with previously non-preferred males after having observed them with a relatively high-quality female. Conversely, females were found to significantly decrease time spent with previously preferred males after having observed them with a relatively low-quality female. Female mate choice copying might be maintained by selection based on the heuristic value it provides females choosing between males whose quality differences are not easily distinguishable. |
Address |
University of Texas at Austin, Department of Psychology, 1 University Station A8000, Austin, TX 78712, USA. sehill@mail.utexas.edu |
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1744-9561 |
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PMID:17148362 |
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no |
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1820 |
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Author |
Uehara, T.; Yokomizo, H.; Iwasa, Y. |
Title |
Mate-choice copying as Bayesian decision making |
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Journal Article |
Year |
2005 |
Publication |
The American naturalist |
Abbreviated Journal |
Am Nat |
Volume |
165 |
Issue |
3 |
Pages |
403-410 |
Keywords |
Animals; *Bayes Theorem; *Choice Behavior; Female; Male; *Models, Biological; *Sexual Behavior, Animal |
Abstract |
Mate-choice copying by females has been reported in fishes (e.g., guppies) and lekking birds. Presumably, females assess males' quality using both information from direct observation of males and information acquired by observing other females' choices. Here, we study mathematically the conditions under which mate-choice copying is advantageous on the basis of Bayesian decision theory. A female may observe the mate choice of another female, called the model female, who has performed an optimal choice based on her own judgment. The conditions required for the focal female to choose the same mate as that chosen by the model female should depend on the male's appearance to her, the reliability of her own judgment of male quality, and the reliability of the model females. When three or more females are involved, the optimal mate choice critically depends on whether multiple model females make decisions independently or they themselves copy the choices of others. If two equally reliable females choose different males, the choice of the second female, made knowing the choice of the first, should have a stronger effect on the choice of the third (focal) female. This “last-choice precedence” should be tested experimentally. |
Address |
Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka 812-8581, Japan. uehara@bio-math.biology.kyushu-u.ac.jp |
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1537-5323 |
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PMID:15729669 |
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1821 |
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Author |
Dugatkin, L.A.; Godin, J.G. |
Title |
Reversal of female mate choice by copying in the guppy (Poecilia reticulata) |
Type |
Journal Article |
Year |
1992 |
Publication |
Proceedings. Biological sciences / The Royal Society |
Abbreviated Journal |
Proc Biol Sci |
Volume |
249 |
Issue |
1325 |
Pages |
179-184 |
Keywords |
Acclimatization; Animals; *Choice Behavior; Female; Male; Poecilia; *Sexual Behavior, Animal |
Abstract |
Ever since Fisher (1958) formalized models of sexual selection, female mate choice has been assumed to be a genetically determined trait. Females, however, may also use social cues to select mates. One such cue might be the mate choice of conspecifics. Here we report the first direct evidence that a female's preference for a particular male can in fact be reversed by social cues. In our experiments using the Trinidadian guppy (Poecilia reticulata), this reversal was mediated by mate-copying opportunities, such that a female (the 'focal' female) is given the opportunity to choose between two males, followed by a period in which she observes a second female (the 'model' female) displaying a preference for the male she herself did not prefer initially. When allowed to choose between the same males a second time, compared with control tests, a significant proportion of focal females reversed their mate choice and copied the preference of the model female. These results provide strong evidence for the role of non-genetic factors in sexual selection and underlie the need for new models of sexual selection that explicitly incorporate both genetic and cultural aspects of mate choice. |
Address |
Department of Biology, Mount Allison University, Sackville, New Brunswick, Canada |
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0962-8452 |
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PMID:1360679 |
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no |
Call Number |
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1824 |
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