Records |
Author |
Harman, A.M.; Moore, S.; Hoskins, R.; Keller, P. |
Title |
Horse vision and an explanation for the visual behaviour originally explained by the 'ramp retina' |
Type |
Journal Article |
Year |
1999 |
Publication |
Equine veterinary journal |
Abbreviated Journal |
Equine Vet J |
Volume |
31 |
Issue |
5 |
Pages |
384-390 |
Keywords |
Animals; Behavior, Animal; Cell Count; Eye/*anatomy & histology; Ganglia, Sensory/cytology; Horses/*physiology; Refractive Errors/veterinary; Retina/cytology/*physiology; Vision/*physiology; Visual Acuity; Visual Fields |
Abstract |
Here we provide confirmation that the 'ramp retina' of the horse, once thought to result in head rotating visual behaviour, does not exist. We found a 9% variation in axial length of the eye between the streak region and the dorsal periphery. However, the difference was in the opposite direction to that proposed for the 'ramp retina'. Furthermore, acuity in the narrow, intense visual streak in the inferior retina is 16.5 cycles per degree compared with 2.7 cycles per degree in the periphery. Therefore, it is improbable that the horse rotates its head to focus onto the peripheral retina. Rather, the horse rotates the nose up high to observe distant objects because binocular overlap is oriented down the nose, with a blind area directly in front of the forehead. |
Address |
Department of Psychology, University of Western Australia, Nedlands, Australia |
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English |
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ISSN |
0425-1644 |
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PMID:10505953 |
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no |
Call Number |
refbase @ user @ |
Serial |
836 |
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Author |
Rapin, V.; Poncet, P.A.; Burger, D.; Mermod, C.; Richard, M.A. |
Title |
[Measurement of the attention time in the horse] |
Type |
Journal Article |
Year |
2007 |
Publication |
Schweizer Archiv fur Tierheilkunde |
Abbreviated Journal |
Schweiz Arch Tierheilkd |
Volume |
149 |
Issue |
2 |
Pages |
77-83 |
Keywords |
Age Factors; Animals; *Attention/physiology; Conditioning, Operant; Cross-Over Studies; Female; Horses/*physiology; Learning/*physiology; Male; Memory/*physiology; Time Factors |
Abstract |
A study carried out on 49 horses showed that it is possible to measure the attention time by operant conditioning. After teaching horses an instrumental task using a signal, we were then able to test their attention time by asking them to prolong it increasingly while setting success and failure criteria. Two tests were performed 3 weeks apart. The 2nd test was feasible without relearning, a proof of memory, and was repeatable, a proof of consistency in the attention time. A significant difference was observed between the 3 age groups. Young horses often performed very well during the 1st test but their attention dropped in the 2nd test while older horses were more stable with respect to attention and even increased it slightly. The study shows that there are individual differences but it was not possible to prove a significant influence of breed, gender and paternal influence. Consequently, learning appears to be one of the most interesting approaches for evaluating the attention of horses and for observing their behaviour. |
Address |
Laboratoire d'Ecoethologie, Universite de Neuchatel, Suisse. veronique.rapin@unine.ch |
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Place of Publication |
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Language |
French |
Summary Language |
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Original Title |
Mesure de la duree d'attention chez le cheval |
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Edition |
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ISSN |
0036-7281 |
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Notes |
PMID:17343134 |
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no |
Call Number |
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Serial |
1770 |
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Author |
Giles, N.; Tupper, J. |
Title |
Equine interspecies aggression |
Type |
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Year |
2006 |
Publication |
The Veterinary record |
Abbreviated Journal |
Vet. Rec. |
Volume |
159 |
Issue |
22 |
Pages |
756 |
Keywords |
Aggression/*physiology; Animals; Horses/*physiology; Sheep/*physiology; Social Dominance |
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English |
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Original Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0042-4900 |
ISBN |
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Notes |
PMID:17127768 |
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no |
Call Number |
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Serial |
1779 |
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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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ISSN |
0022-0949 |
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Notes |
PMID:17079726 |
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no |
Call Number |
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Serial |
1782 |
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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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English |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0165-2176 |
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Notes |
PMID:11765239 |
Approved |
no |
Call Number |
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Serial |
1807 |
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Author |
Bobbert, M.F.; Santamaria, S. |
Title |
Contribution of the forelimbs and hindlimbs of the horse to mechanical energy changes in jumping |
Type |
Journal Article |
Year |
2005 |
Publication |
The Journal of Experimental Biology |
Abbreviated Journal |
J Exp Biol |
Volume |
208 |
Issue |
2 |
Pages |
249-260 |
Keywords |
Animals; Biomechanics; Forelimb/*physiology; Hindlimb/*physiology; Horses/*physiology; Locomotion/*physiology; Muscle, Skeletal/*physiology; Time Factors |
Abstract |
The purpose of the present study was to gain more insight into the contribution of the forelimbs and hindlimbs of the horse to energy changes during the push-off for a jump. For this purpose, we collected kinematic data at 240 Hz from 23 5-year-old Warmbloods (average mass: 595 kg) performing free jumps over a 1.15 m high fence. From these data, we calculated the changes in mechanical energy and the changes in limb length and joint angles. The force carried by the forelimbs and the amount of energy stored was estimated from the distance between elbow and hoof, assuming that this part of the leg behaved as a linear spring. During the forelimb push, the total energy first decreased by 3.2 J kg(-1) and then increased again by 4.2 J kg(-1) to the end of the forelimb push. At the end of the forelimb push, the kinetic energy due to horizontal velocity of the centre of mass was 1.6 J kg(-1) less than at the start, while the effective energy (energy contributing to jump height) was 2.3 J kg(-1) greater. It was investigated to what extent these changes could involve passive spring-like behaviour of the forelimbs. The amount of energy stored and re-utilized in the distal tendons during the forelimb push was estimated to be on average 0.4 J kg(-1) in the trailing forelimb and 0.23 J kg(-1) in the leading forelimb. This means that a considerable amount of energy was first dissipated and subsequently regenerated by muscles, with triceps brachii probably being the most important contributor. During the hindlimb push, the muscles of the leg were primarily producing energy. The total increase in energy was 2.5 J kg(-1) and the peak power output amounted to 71 W kg(-1). |
Address |
Institute for Fundamental and Clinical Human Movement Sciences, Vrije Universiteit, van der Boechorstraat 9, NL-1081 BT Amsterdam, The Netherlands. MFBobbert@fbw.vu.nl |
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English |
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Edition |
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ISSN |
0022-0949 |
ISBN |
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Notes |
PMID:15634844 |
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no |
Call Number |
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Serial |
1895 |
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Author |
Belonje, P.C.; van Niekerk, C.H. |
Title |
A review of the influence of nutrition upon the oestrous cycle and early pregnancy in the mare |
Type |
Journal Article |
Year |
1975 |
Publication |
Journal of Reproduction and Fertility. Supplement |
Abbreviated Journal |
J Reprod Fertil Suppl |
Volume |
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Issue |
23 |
Pages |
167-169 |
Keywords |
Animals; Body Weight; *Diet; *Estrus; Female; Fertility; Fetal Resorption/prevention & control; Horses/*physiology; Pregnancy |
Abstract |
Attention is drawn to the beneficial effect of improved nutrition during winter and early spring on the ovarian activity of mares. Furthermore, the necessity of an adequate plane of nutrition during early pregnancy to prevent embryonic resorption is stressed. |
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English |
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Edition |
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ISSN |
0449-3087 |
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Notes |
PMID:1060772 |
Approved |
no |
Call Number |
Equine Behaviour @ team @ |
Serial |
2225 |
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Author |
Hawkes, J.; Hedges, M.; Daniluk, P.; Hintz, H.F.; Schryver, H.F. |
Title |
Feed preferences of ponies |
Type |
Journal Article |
Year |
1985 |
Publication |
Equine Veterinary Journal |
Abbreviated Journal |
Equine Vet J |
Volume |
17 |
Issue |
1 |
Pages |
20-22 |
Keywords |
*Animal Feed; Animals; Feeding Behavior/physiology; Female; *Food Preferences; Horses/*physiology; Male |
Abstract |
Preference trials were conducted with mature ponies. In Trial 1, oats were compared with oats plus sucrose. Four of six pony geldings selected oats plus sucrose, but one pony demonstrated a dislike for sucrose and one selected from the bucket on the right side regardless of content. Oats, maize, barley, rye and wheat were compared in Trial 2 using six mature pony mares. Oats were the preferred grain, with maize and barley ranking second and third respectively. Wheat and rye were the least preferred. Even though the ponies demonstrated preference, the total intake at a given meal was not greatly depressed when only the less palatable grains were fed. In Trial 3, pony mares selected a diet containing 20 per cent dried distillers' grain and 80 per cent of a basal mixed diet of maize, oats, wheat bran, soybean meal, limestone and molasses over 100 per cent basal mixed diet, but selected the basal diet over diets containing 20 per cent blood meal, beet pulp or meat and bone meal and 80 per cent basal diet. They did not differentiate against diets containing 20 per cent alfalfa meal or 10 or 5 per cent meat and bone meal when the diets were compared to the basal mixed diet. |
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English |
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ISSN |
0425-1644 |
ISBN |
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Notes |
PMID:3979369 |
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no |
Call Number |
Equine Behaviour @ team @ |
Serial |
2298 |
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Author |
Heird, J.C.; Lennon, A.M.; Bell, R.W. |
Title |
Effects of early experience on the learning ability of yearling horses |
Type |
Journal Article |
Year |
1981 |
Publication |
Journal of Animal Science |
Abbreviated Journal |
J. Anim Sci. |
Volume |
53 |
Issue |
5 |
Pages |
1204-1209 |
Keywords |
Animals; Conditioning (Psychology); Female; *Handling (Psychology); Horses/*physiology; *Learning |
Abstract |
Twenty-four yearling Quarter Horse fillies were divided into three groups (I) very limited handling, (II) intermediate handling and (III) extensive handling. At about 14 months of age, each horse was preconditioned for 2 weeks and then run in a simple place-learning T-maze test in which it had to locate its feed. Thirty trials were run daily for 20 days, with the location of the feed changed each day. To retire from the maze, a horse had to meet the criterion: 11 correct responses in 12 tries, with the last eight being consecutive. Horses in Group II required the fewest trials to reach criterion. These horses also learned more and had the highest percentage of correct responses (P less than .05). Mean trainability tended to predict learning ability; however, trainability and trials to criterion were not significantly correlated. Mean emotionality scores indicated a tendency for horses in the intermediately handled group to be less emotional than those in Group I or III. Results indicated that horses with an intermediate amount of handling scored higher on an intermediate test of learning. All handled horses scored higher on learning tests than those not handled. |
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0021-8812 |
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Notes |
PMID:7319966 |
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no |
Call Number |
Equine Behaviour @ team @ |
Serial |
3577 |
Permanent link to this record |
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Author |
Timney, B.; Keil, K. |
Title |
Local and global stereopsis in the horse |
Type |
Journal Article |
Year |
1999 |
Publication |
Vision Research |
Abbreviated Journal |
Vision Res |
Volume |
39 |
Issue |
10 |
Pages |
1861-1867 |
Keywords |
Animals; Depth Perception/*physiology; Female; Horses/*physiology; Pattern Recognition, Visual/physiology; Psychophysics; Sensory Thresholds/physiology; Vision, Binocular/physiology; Vision, Monocular/physiology |
Abstract |
Although horses have laterally-placed eyes, there is substantial binocular overlap, allowing for the possibility that these animals have stereopsis. In the first experiment of the present study we measured local stereopsis by obtaining monocular and binocular depth thresholds for renal depth stimuli. On all measures, the horses' binocular performance was superior to their monocular. When depth thresholds were obtained, binocular thresholds were several times superior to those obtained monocularly, suggesting that the animals could use stereoscopic information when it was available. The binocular thresholds averaged about 15 min arc. In the second experiment we obtained evidence for the presence of global stereopsis by testing the animals' ability to discriminate between random-dot stereograms with and without consistent disparity information. When presented with such stimuli they showed a strong preference for the cyclopean equivalent of the positive stimulus with the real depth. These results provide the first behavioral demonstration of a full range of stereoscopic skills in a lateral-eyed mammal. |
Address |
Department of Psychology, Faculty of Social Science, University of Western Ontario, London, Canada. timney@julian.uwo.ca |
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Edition |
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ISSN |
0042-6989 |
ISBN |
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Notes |
PMID:10343877 |
Approved |
yes |
Call Number |
Equine Behaviour @ team @ |
Serial |
3580 |
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