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 ![sorted by Address field, descending order (down)](img/sort_desc.gif) |
Department of Psychology, University of Western Australia, Nedlands, Australia |
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English |
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0425-1644 |
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Notes |
PMID:10505953 |
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no |
Call Number |
refbase @ user @ |
Serial |
836 |
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Author |
Devenport, J.A.; Patterson, M.R.; Devenport, L.D. |
Title |
Dynamic averaging and foraging decisions in horses (Equus callabus) |
Type |
Journal Article |
Year |
2005 |
Publication |
Journal of Comparative psychology |
Abbreviated Journal |
J. Comp. Psychol. |
Volume |
119 |
Issue |
3 |
Pages |
352-358 |
Keywords |
Animals; *Decision Making; *Feeding Behavior; Female; Horses/*psychology; Male; *Memory, Short-Term; Motivation; Orientation; *Social Environment |
Abstract |
The variability of most environments taxes foraging decisions by increasing the uncertainty of the information available. One solution to the problem is to use dynamic averaging, as do some granivores and carnivores. Arguably, the same strategy could be useful for grazing herbivores, even though their food renews and is more homogeneously distributed. Horses (Equus callabus) were given choices between variable patches after short or long delays. When patch information was current, horses returned to the patch that was recently best, whereas those without current information matched choices to the long-term average values of the patches. These results demonstrate that a grazing species uses dynamic averaging and indicate that, like granivores and carnivores, they can use temporal weighting to optimize foraging decisions. |
Address ![sorted by Address field, descending order (down)](img/sort_desc.gif) |
Department of Psychology, University of Central Oklahoma, 73034, USA. jdevenport@ucok.edu |
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ISSN |
0735-7036 |
ISBN |
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Notes |
PMID:16131264 |
Approved |
no |
Call Number |
refbase @ user @ |
Serial |
752 |
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Author |
Henderson, A.J.Z. |
Title |
Don't fence me in: managing psychological well being for elite performance horses |
Type |
Journal Article |
Year |
2007 |
Publication |
Journal of Applied Animal Welfare Science : JAAWS |
Abbreviated Journal |
J. Appl. Anim. Welf. Sci. |
Volume |
10 |
Issue |
4 |
Pages |
309-329 |
Keywords |
*Animal Husbandry; Animal Welfare; Animals; *Behavior, Animal; Horses/*psychology; *Physical Conditioning, Animal; *Stereotyped Behavior |
Abstract |
This article posits that stereotypical behavior patterns and the overall psychological well being of today's performance horse could be substantially enhanced with care that acknowledges the relationship between domesticated horses and their forerunners. Feral horses typically roam in stable, social groups over large grazing territories, spending 16-20 hr per day foraging on mid- to poor-quality roughage. In contrast, today's elite show horses live in relatively small stalls, eat a limited-but rich-diet at specific feedings, and typically live in social isolation. Although the horse has been domesticated for more than 6000 years, there has been no selection for an equid who no longer requires an outlet for these natural behaviors. Using equine stereotypies as a welfare indicator, this researcher proposes that the psychological well being of today's performance horse is compromised. Furthermore, the article illustrates how minimal management changes can enhance horses' well being while still remaining compatible with the requirements of the sport-horse industry. The article discusses conclusions in terms of Fraser, Weary, Pajor, and Milligan's “integrative welfare model” (1997). |
Address ![sorted by Address field, descending order (down)](img/sort_desc.gif) |
Department of Psychology, Simon Fraser University, Burnaby, British Columbia, Canada. zamoyska@shaw.ca |
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ISSN |
1088-8705 |
ISBN |
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Conference |
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Notes |
PMID:17970632 |
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no |
Call Number |
Equine Behaviour @ team @ |
Serial |
4363 |
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Author |
Dougherty, D.M.; Lewis, P. |
Title |
Stimulus generalization, discrimination learning, and peak shift in horses |
Type |
Journal Article |
Year |
1991 |
Publication |
Journal of the experimental analysis of behavior |
Abbreviated Journal |
J Exp Anal Behav |
Volume |
56 |
Issue |
1 |
Pages |
97-104 |
Keywords |
Animals; *Appetitive Behavior; Attention; *Conditioning, Operant; *Discrimination Learning; Female; *Generalization, Stimulus; Horses/*psychology; Male; *Pattern Recognition, Visual; Size Perception |
Abstract |
Using horses, we investigated three aspects of the stimulus control of lever-pressing behavior: stimulus generalization, discrimination learning, and peak shift. Nine solid black circles, ranging in size from 0.5 in. to 4.5 in. (1.3 cm to 11.4 cm) served as stimuli. Each horse was shaped, using successive approximations, to press a rat lever with its lip in the presence of a positive stimulus, the 2.5-in. (6.4-cm) circle. Shaping proceeded quickly and was comparable to that of other laboratory organisms. After responding was maintained on a variable-interval 30-s schedule, stimulus generalization gradients were collected from 2 horses prior to discrimination training. During discrimination training, grain followed lever presses in the presence of a positive stimulus (a 2.5-in circle) and never followed lever presses in the presence of a negative stimulus (a 1.5-in. [3.8-cm] circle). Three horses met a criterion of zero responses to the negative stimulus in fewer than 15 sessions. Horses given stimulus generalization testing prior to discrimination training produced symmetrical gradients; horses given discrimination training prior to generalization testing produced asymmetrical gradients. The peak of these gradients shifted away from the negative stimulus. These results are consistent with discrimination, stimulus generalization, and peak-shift phenomena observed in other organisms. |
Address ![sorted by Address field, descending order (down)](img/sort_desc.gif) |
Department of Psychology, Ohio University, Athens 45701 |
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English |
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ISSN |
0022-5002 |
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Conference |
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Notes |
PMID:1940765 |
Approved |
no |
Call Number |
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Serial |
1764 |
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Author |
Miyashita, Y.; Nakajima, S.; Imada, H. |
Title |
Panel-touch behavior of horses established by an autoshaping procedure |
Type |
Journal Article |
Year |
1999 |
Publication |
Psychological Reports |
Abbreviated Journal |
Psychol Rep |
Volume |
85 |
Issue |
3 Pt 1 |
Pages |
867-868 |
Keywords |
Animals; Behavior, Animal/*physiology; Conditioning (Psychology)/*physiology; Horses/physiology; *Touch |
Abstract |
Panel-touch behavior of 3 geldings was successfully established by a response-termination type of autoshaping procedure. An omission or negative contingency introduced after the training of an animal, however, decreased the response rate to a near-zero level. |
Address ![sorted by Address field, descending order (down)](img/sort_desc.gif) |
Department of Psychology, Kwansei Gakuin University, Nishinomiya, Japan |
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ISSN |
0033-2941 |
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Notes |
PMID:10672748 |
Approved |
no |
Call Number |
refbase @ user @ |
Serial |
1926 |
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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 ![sorted by Address field, descending order (down)](img/sort_desc.gif) |
Department of Psychology, Faculty of Social Science, University of Western Ontario, London, Canada. timney@julian.uwo.ca |
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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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Author |
Bannasch, D.; Rinaldo, C.; Millon, L.; Latson, K.; Spangler, T.; Hubberty, S.; Galuppo, L.; Lowenstine, L. |
Title |
SRY negative 64,XX intersex phenotype in an American saddlebred horse |
Type |
Journal Article |
Year |
2007 |
Publication |
Veterinary Journal (London, England : 1997) |
Abbreviated Journal |
Vet J |
Volume |
173 |
Issue |
2 |
Pages |
437-439 |
Keywords |
Animals; Female; Genitalia/abnormalities; Hermaphroditism/*veterinary; Horse Diseases/*diagnosis/genetics; Horses/*genetics/*physiology; Karyotyping; Phenotype; Sex Differentiation; Sex Differentiation Disorders/diagnosis/veterinary; Sex-Determining Region Y Protein/genetics/*metabolism |
Abstract |
A female American saddlebred horse was presented for surgical correction of a possible pseudohermaphrodite condition. The horse had abnormal external genitalia and exhibited stallion-like behaviour. No evidence of uterine or ovarian tissue was identified on laparoscopic examination, but hypoplastic testicular-like tissue was removed, although this was found to contain no spermatogonia upon histopathological examination. A karyotype was performed and showed the normal chromosomal complement for a female horse (64,XX). Polymerase chain reaction to detect the SRY gene was negative in peripheral blood as well as the testicular-like tissue. This case represents the first report of an SRY negative XX-male sex reversal intersex phenotype, which is a potentially inherited condition, in an American saddlebred horse. |
Address ![sorted by Address field, descending order (down)](img/sort_desc.gif) |
Department of Population Health and Reproduction, School of Veterinary Medicine, University of California, Davis, CA 95616, USA. dlbannasch@ucdavis.edu |
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English |
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Series Volume |
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Edition |
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ISSN |
1090-0233 |
ISBN |
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Notes |
PMID:16386440 |
Approved |
no |
Call Number |
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Serial |
1882 |
Permanent link to this record |
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Author |
Williams, D.O.; Boatwright, R.B.; Rugh, K.S.; Garner, H.E.; Griggs, D.M.J. |
Title |
Myocardial blood flow, metabolism, and function with repeated brief coronary occlusions in conscious ponies |
Type |
Journal Article |
Year |
1991 |
Publication |
The American journal of physiology |
Abbreviated Journal |
Am J Physiol |
Volume |
260 |
Issue |
1 Pt 2 |
Pages |
H100-9 |
Keywords |
Animals; Consciousness/*physiology; Coronary Circulation/*physiology; Coronary Disease/pathology/*physiopathology; Disease Models, Animal; Hemodynamic Processes/physiology; Horses/*physiology; Hydrogen/metabolism; Lactates/metabolism; Myocardium/*metabolism/pathology; Norepinephrine/metabolism; Potassium/metabolism; Regional Blood Flow |
Abstract |
Studies were performed in the conscious pony instrumented with a Doppler flow probe and hydraulic occluder on the left anterior descending coronary artery (LAD), sonomicrometry crystals and intraventricular micromanometer in the left ventricle, and catheters in the left atrium and anterior interventricular vein. Two-minute LAD occlusions were performed every 30 min continuously or during working hours. Data on release of catabolites (potassium, hydrogen ions, and lactate) and norepinephrine from the initially dysfunctional region were obtained periodically during a regimen of 445 +/- 56 occlusions in six animals. Regional myocardial blood flow was measured (microsphere method) before and after an occlusion regimen in four animals. Marked release of catabolites and norepinephrine from the initially dysfunctional region was noted in association with early occlusions when myocardial segment function was severely reduced. With further occlusions, release of these substances decreased while segment function improved. Blood flow was markedly decreased in the initially dysfunctional region during an early occlusion but was at the control level during a later occlusion. Although the metabolic findings are consistent with protection due to “ischemic preconditioning” and no increase in collateral perfusion, the inverse relationship noted between catabolite release and segment function is best explained by flow-dependent mechanisms. These results, together with the myocardial blood flow data, serve to validate a previous assumption that protection against regional myocardial dysfunction under these conditions is due to increased collateral perfusion. |
Address ![sorted by Address field, descending order (down)](img/sort_desc.gif) |
Department of Physiology, University of Missouri, Columbia 65212 |
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English |
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ISSN |
0002-9513 |
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Notes |
PMID:1992786 |
Approved |
no |
Call Number |
refbase @ user @ |
Serial |
98 |
Permanent link to this record |
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Author |
Shaw, E.B.; Houpt, K.A.; Holmes, D.F. |
Title |
Body temperature and behaviour of mares during the last two weeks of pregnancy |
Type |
Journal Article |
Year |
1988 |
Publication |
Equine veterinary journal |
Abbreviated Journal |
Equine Vet J |
Volume |
20 |
Issue |
3 |
Pages |
199-202 |
Keywords |
Animals; *Behavior, Animal; *Body Temperature; Circadian Rhythm; Eating; Female; Horses/*physiology; Labor, Obstetric/*physiology; Motor Activity; Pregnancy; Pregnancy, Animal/*physiology |
Abstract |
Average daily core body temperature and behavioural patterns of pregnant mares were studied, in search of definitive signs of parturition within 24 h of the event. Nineteen pony mares were sampled twice daily for core body temperature. A significant temperature drop, averaging 0.1 degrees C (0.2 degrees F) was observed during the day prior to parturition. Between 18.00 h and 06.00 h, during the two weeks before parturition, Thoroughbred and Standardbred mares (n = 52) spent an average 66.8 per cent of their time standing, 27.0 per cent eating, 4.9 per cent lying in sternal recumbency, 1.0 per cent lying in lateral recumbency, and 0.3 per cent walking. On the night before parturition, mares spent significantly less time lying in sternal recumbency than on previous nights and on the night of parturition all behaviour patterns except eating were significantly different from the nights of the two weeks before parturition. There was an increase in walking (5.3 per cent), lying in sternal recumbency (8 per cent) and lying in lateral recumbency (5.3 per cent) whereas standing (53.3 per cent) was decreased. In 58 observed pregnancies, 54 mares (97 per cent) foaled in a recumbent position and 50 mares (86 per cent) foaled between 18.00 h and 06.00 h. |
Address ![sorted by Address field, descending order (down)](img/sort_desc.gif) |
Department of Physiology, New York State College of Veterinary Medicine, Cornell University, Ithaca 14853 |
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0425-1644 |
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Conference |
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Notes |
PMID:3402416 |
Approved |
no |
Call Number |
refbase @ user @ |
Serial |
46 |
Permanent link to this record |
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Author |
Houpt, K.A.; Perry, P.J.; Hintz, H.F.; Houpt, T.R. |
Title |
Effect of meal frequency on fluid balance and behavior of ponies |
Type |
Journal Article |
Year |
1988 |
Publication |
Physiology & behavior |
Abbreviated Journal |
Physiol. Behav. |
Volume |
42 |
Issue |
5 |
Pages |
401-407 |
Keywords |
Animals; Behavior, Animal/*physiology; Blood Proteins/analysis; *Eating; Female; Hematocrit; Horses/blood/*physiology; Osmolar Concentration; *Water-Electrolyte Balance |
Abstract |
Twelve ponies were fed their total daily ration either as one large meal or divided into six small meals. Pre- and post-feeding behavior was recorded six times a day. Blood samples were taken for 30 min before and two hr after the meal. Plasma protein increased from 7.0 to a peak of 7.3 g/dl with small meals and from 7.3 to 8.1 g/dl with large meals, and returned to pre-feeding levels by 90 min post-feeding. Hematocrit rose from 33.3 to 34.1% with small meals and from 33.0 to 36.0% with large meals. These rapid and short-lived increases indicate a decrease in plasma volume. Plasma osmolality rose with feeding from 283 to 285 mosmoles/kg with small meals and from 281 to 288 mosmoles/kg with large meals. Water availability had no significant effect on blood changes. Digestibility and rate of passage were measured with chromic oxide, but there were no differences. Vocalizing (neighing) and walking occurred more often before than after feeding, while eating bedding and engaging in other oral behaviors were more frequent after feeding. |
Address ![sorted by Address field, descending order (down)](img/sort_desc.gif) |
Department of Physiology, New York State College of Veterinary Medicine, Cornell University, Ithaca 14853 |
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ISSN |
0031-9384 |
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Notes |
PMID:3393599 |
Approved |
no |
Call Number |
refbase @ user @ |
Serial |
47 |
Permanent link to this record |