| Records |
Author  |
Hanggi, E.B.; Ingersoll, J.F. |
| Title |
Stimulus discrimination by horses under scotopic conditions |
Type |
Journal Article |
| Year |
2009 |
Publication |
Behavioural Processes |
Abbreviated Journal |
Behav. Process. |
| Volume |
82 |
Issue |
1 |
Pages |
45-50 |
| Keywords |
Discrimination learning; Equine; Horse; Night vision; Scotopic vision |
| Abstract |
Scotopic vision in horses (Equus caballus) was investigated using behavioral measurements for the first time. Four horses were tested for the ability to make simple visual discriminations of geometric figures (circles and triangles) under various brightness levels within an enclosed building. Measurements of brightness ranging from 10.37 to 24.12 magnitudes per square arcsecond (mag/arcsec2; in candelas per square meter--7.70 to 2.43E-05 cd/m2) were taken using a Sky Quality Meter. These values approximated outdoor conditions ranging from twilight in open country to a dark moonless night in dense forest. The horses were able to solve the discrimination problems in all brightness settings up to 23.77 mag/arcsec2 (3.35E-05 cd/m2). Moreover, they easily navigated their way around obstacles located within the testing area in extremely dim light (>23.50 mag/arcsec2; 4.30E-05 cd/m2), which were in conditions too dark for the human experimenters to see. These findings support physiological data that reveal a rod-dominated visual system as well as observations of equine activity at night. |
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| ISSN |
0376-6357 |
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| Call Number |
Equine Behaviour @ team @ |
Serial |
5051 |
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| Author |
Hanggi, E.B.; Ingersoll, J.F.; Waggoner, T.L. |
| Title |
Color vision in horses (Equus caballus): deficiencies identified using a pseudoisochromatic plate test |
Type |
Journal Article |
| Year |
2007 |
Publication |
Journal of Comparative Psychology |
Abbreviated Journal |
J. Comp. Psychol. |
| Volume |
121 |
Issue |
1 |
Pages |
65-72 |
| Keywords |
Animals; Appetitive Behavior; *Color Perception; Color Perception Tests/veterinary; *Discrimination Learning; Female; Horses/*psychology; Male; Sensitivity and Specificity |
| Abstract |
In the past, equine color vision was tested with stimuli composed either of painted cards or photographic slides or through physiological testing using electroretinogram flicker photometry. Some studies produced similar results, but others did not, demonstrating that there was not yet a definitive answer regarding color vision in horses (Equus caballus). In this study, a pseudoisochromatic plate test--which is highly effective in testing color vision both in small children and in adult humans--was used for the first time on a nonhuman animal. Stimuli consisted of different colored dotted circles set against backgrounds of varying dots. The coloration of the circles corresponded to the visual capabilities of different types of color deficiencies (anomalous trichromacy and dichromacy). Four horses were tested on a 2-choice discrimination task. All horses successfully reached criterion for gray circles and demonstration circles. None of the horses were able to discriminate the protan-deutan plate or the individual protan or deutan plates. However, all were able to discriminate the tritan plate. The results suggest that horses are dichromats with color vision capabilities similar to those of humans with red-green color deficiencies. |
| Address |
Equine Research Foundation, Aptos, CA 95001, USA. EquiResF@aol.com |
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English |
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Edition |
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| ISSN |
0735-7036 |
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| Notes |
PMID:17324076 |
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no |
| Call Number |
refbase @ user @ ; Equine Behaviour @ team @ room B 3.029 |
Serial |
1972 |
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| Author |
Hansen, M.N.; Estvan, J.; Ladewig, J. |
| Title |
A note on resting behaviour in horses kept on pasture: Rolling prior to getting up |
Type |
Journal Article |
| Year |
2007 |
Publication |
Applied Animal Behaviour Science |
Abbreviated Journal |
Appl. Anim. Behav. Sci. |
| Volume |
105 |
Issue |
1-3 |
Pages |
265-269 |
| Keywords |
Resting behaviour; Recumbency; Rolling behaviour; Rising behaviour; Horses; Comfort behaviour |
| Abstract |
In previous studies on lying behaviour in horses kept in individual boxes we observed that most horses that had been lying down resting sometimes made a rolling behaviour prior to getting up. The rolling behaviour was seen in approximately 30% of the times the horses stood up. To analyse whether the behaviour was caused by individual housing in a box or whether it is a behaviour occurring also under free range conditions, we observed a group of 43 horses kept on pasture throughout the day and night. The horses were observed from 03:00 to 10:00 h over four consecutive mornings, at a time when lying behaviour was frequent. Of the 43 horses observed, the rising procedure was seen in 41 horses, and 25 of these horses (60.9%) performed the rolling behaviour at least once. A total of 135 rising episodes were observed, and 41 followed the performance of a rolling behaviour (30.4%). In contrast to the rolling behaviour seen indoors, the behaviour was more varied outdoors in that some horses rolled anywhere from 45 to 180[degree sign], some even repeatedly, whereas horses in a box only rolled 90[degree sign] and back. In all cases when horses rolled 180[degree sign] they rolled back to the original side before getting up. Also in contrast to previous observations, no horse was observed changing position during the roll. We conclude that the behaviour is a kind of comfort behaviour but that further studies are necessary to explain its function. |
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no |
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refbase @ user @ |
Serial |
288 |
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| Author |
Hanson, R.P.; Trainer, D.O. |
| Title |
Significance of changing ecology on the epidemiology of arboviruses in the United States |
Type |
Journal Article |
| Year |
1969 |
Publication |
Proceedings, Annual Meeting of the United States Animal Health Association |
Abbreviated Journal |
Proc Annu Meet U S Anim Health Assoc |
| Volume |
73 |
Issue |
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Pages |
291-294 |
| Keywords |
Animals; Arthropod Vectors; Disease Reservoirs; *Ecology; *Encephalitis, Arbovirus; *Horse Diseases; Horses; Humans; United States |
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English |
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Edition |
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| ISSN |
0082-8750 |
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| Notes |
PMID:5278181 |
Approved |
no |
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Equine Behaviour @ team @ |
Serial |
2742 |
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| Author |
Hardy, J.L. |
| Title |
The ecology of western equine encephalomyelitis virus in the Central Valley of California, 1945-1985 |
Type |
Journal Article |
| Year |
1987 |
Publication |
The American Journal of Tropical Medicine and Hygiene |
Abbreviated Journal |
Am J Trop Med Hyg |
| Volume |
37 |
Issue |
3 Suppl |
Pages |
18s-32s |
| Keywords |
Aedes/microbiology; Animals; Birds; California; Culex/microbiology; Encephalitis Virus, Western Equine/*physiology; Encephalomyelitis, Equine/*history/microbiology/transmission/veterinary; History, 20th Century; Horse Diseases/history/transmission; Horses; Humans; Insect Vectors/microbiology; Mammals |
| Abstract |
Reeves' concept of the summer transmission cycle of western equine encephalomyelitis virus in 1945 was that the virus was amplified in a silent transmission cycle involving mosquitoes, domestic chickens, and possibly wild birds, from which it could be transmitted tangentially to and cause disease in human and equine populations. Extensive field and laboratory studies done since 1945 in the Central Valley of California have more clearly defined the specific invertebrate and vertebrate hosts involved in the basic virus transmission cycle, but the overall concept remains unchanged. The basic transmission cycle involves Culex tarsalis as the primary vector mosquito species and house finches and house sparrows as the primary amplifying hosts. Secondary amplifying hosts, upon which Cx. tarsalis frequently feeds, include other passerine species, chickens, and possibly pheasants in areas where they are abundant. Another transmission cycle that most likely is initiated from the Cx. tarsalis-wild bird cycle involves Aedes melanimon and the blacktail jackrabbit. Like humans and horses, California ground squirrels, western tree squirrels, and a few other wild mammal species become infected tangentially with the virus but do not contribute significantly to virus amplification. |
| Address |
Department of Biomedical and Environmental Health Sciences, School of Public Health, University of California, Berkeley 94720 |
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English |
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Edition |
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| ISSN |
0002-9637 |
ISBN |
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| Notes |
PMID:3318522 |
Approved |
no |
| Call Number |
Equine Behaviour @ team @ |
Serial |
2677 |
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| Author |
Harkins, J.D.; Kamerling, S.G.; Church, G. |
| Title |
Effect of competition on performance of thoroughbred racehorses |
Type |
Journal Article |
| Year |
1992 |
Publication |
Journal of Applied Physiology (Bethesda, Md. : 1985) |
Abbreviated Journal |
J Appl Physiol |
| Volume |
72 |
Issue |
3 |
Pages |
836-841 |
| Keywords |
Age Factors; Animals; Anxiety/physiopathology; Competitive Behavior/*physiology; Exertion/*physiology; Fatigue/physiopathology; Female; Heart Rate; Horses/*physiology; Lactates/blood; Lactic Acid; Male; Sex Characteristics |
| Abstract |
The effect of competition and the influence of age and sex on performance were examined in a study of 18 Thoroughbred racehorses. The horses performed two solo and two competitive runs at 1,200 and 1,600 m for a total of eight runs. No group ran faster during competition, which may have been a reflection of the quality of horses used for this study and their susceptibility to stress-induced impairment of performance. Males showed no significant difference between competitive and solo run times, whereas females were consistently slower during competition. Males ran significantly faster than females in all runs. There was no difference in run times due to age, which may have been due to the high mean age (5.9 yr) of the group. The slower competitive run times may have occurred because of an earlier onset of fatigue when compared with solo runs. Plasma lactate was significantly greater for the 1,200-m competitive than for the solo runs. |
| Address |
Department of Veterinary Physiology, Pharmacology, and Toxicology, School of Veterinary Medicine, Louisiana State University, Baton Rouge 70803 |
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English |
Summary Language |
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Series Title |
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Series Issue |
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Edition |
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| ISSN |
8750-7587 |
ISBN |
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| Notes |
PMID:1568979 |
Approved |
no |
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refbase @ user @ |
Serial |
1947 |
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| Author |
Harland, M.M.; Stewart, A.J.; Marshall, A.E.; Belknap, E.B. |
| Title |
Diagnosis of deafness in a horse by brainstem auditory evoked potential |
Type |
Journal Article |
| Year |
2006 |
Publication |
The Canadian Veterinary Journal. La Revue Veterinaire Canadienne |
Abbreviated Journal |
Can Vet J |
| Volume |
47 |
Issue |
2 |
Pages |
151-154 |
| Keywords |
Acoustic Stimulation/veterinary; Animals; Deafness/congenital/diagnosis/*veterinary; Evoked Potentials, Auditory, Brain Stem/*physiology; Horse Diseases/congenital/*diagnosis; Horses; Male; Pigmentation/physiology; Sensitivity and Specificity |
| Abstract |
Deafness was confirmed in a blue-eyed, 3-year-old, overo paint horse by brainstem auditory evoked potential. Congenital inherited deafness associated with lack of facial pigmentation was suspected. Assessment of hearing should be considered, especially in paint horses, at the time of pre-purchase examination. Brainstem auditory evoked potential assessment is well tolerated and accurate. |
| Address |
Department of Clinical Sciences, College of Veterinary Medicine, Auburn University, Wire Road, Auburn, Alabama, USA |
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English |
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Edition |
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| ISSN |
0008-5286 |
ISBN |
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| Notes |
PMID:16579041 |
Approved |
no |
| Call Number |
Equine Behaviour @ team @ |
Serial |
5680 |
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| 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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Edition |
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| ISSN |
0425-1644 |
ISBN |
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| Notes |
PMID:10505953 |
Approved |
no |
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refbase @ user @ |
Serial |
836 |
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| Author |
Hartmann, E.; Christensen, J.W.; McGreevy, P.D. |
| Title |
Dominance and Leadership: Useful Concepts in Human-Horse Interactions? |
Type |
Journal Article |
| Year |
2017 |
Publication |
Journal of Equine Veterinary Science |
Abbreviated Journal |
Proceedings of the 2017 Equine Science Symposium |
| Volume |
52 |
Issue |
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Pages |
1-9 |
| Keywords |
Horse; Social order; Dominance hierarchy; Aggression; Injury; Learning; Training |
| Abstract |
Dominance hierarchies in horses primarily influence priority access to limited resources of any kind, resulting in predictable contest outcomes that potentially minimize aggressive encounters and associated risk of injury. Levels of aggression in group-kept horses under domestic conditions have been reported to be higher than in their feral counterparts but can often be attributed to suboptimal management. Horse owners often express concerns about the risk of injuries occurring in group-kept horses, but these concerns have not been substantiated by empirical investigations. What has not yet been sufficiently addressed are human safety aspects related to approaching and handling group-kept horses. Given horse's natural tendency to synchronize activity to promote group cohesion, questions remain about how group dynamics influence human-horse interactions. Group dynamics influence a variety of management scenarios, ranging from taking a horse out of its social group to the prospect of humans mimicking the horse's social system by taking a putative leadership role and seeking after an alpha position in the dominance hierarchy to achieve compliance. Yet, there is considerable debate about whether the roles horses attain in their social group are of any relevance in their reactions to humans. This article reviews the empirical data on social dynamics in horses, focusing on dominance and leadership theories and the merits of incorporating those concepts into the human-horse context. This will provide a constructive framework for informed debate and valuable guidance for owners managing group-kept horses and for optimizing human-horse interactions. |
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Edition |
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0737-0806 |
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no |
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Equine Behaviour @ team @ |
Serial |
6712 |
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| Author |
Haruta, N.; Kitagawa, T. |
| Title |
Time-resolved UV resonance Raman investigation of protein folding using a rapid mixer: characterization of kinetic folding intermediates of apomyoglobin |
Type |
Journal Article |
| Year |
2002 |
Publication |
Biochemistry |
Abbreviated Journal |
Biochemistry |
| Volume |
41 |
Issue |
21 |
Pages |
6595-6604 |
| Keywords |
Animals; Apoproteins/*chemistry; Circular Dichroism; Holoenzymes/chemistry; Horses; Hydrochloric Acid/chemistry; Hydrogen-Ion Concentration; Imidazoles/chemistry; Kinetics; Models, Molecular; Myoglobin/*chemistry; Peptide Fragments/chemistry; *Protein Folding; Protein Structure, Secondary; Spectrum Analysis, Raman/*methods; Tryptophan/*chemistry; Ultraviolet Rays; Whales |
| Abstract |
The 244-nm excited transient UV resonance Raman spectra are observed for the refolding intermediates of horse apomyoglobin (h-apoMb) with a newly constructed mixed flow cell system, and the results are interpreted on the basis of the spectra observed for the equilibrium acid unfolding of the same protein. The dead time of mixing, which was determined with the appearance of UV Raman bands of imidazolium upon mixing of imidazole with acid, was 150 micros under the flow rate that was adopted. The pH-jump experiments of h-apoMb from pH 2.2 to 5.6 conducted with this device demonstrated the presence of three folding intermediates. On the basis of the analysis of W3 and W7 bands of Trp7 and Trp14, the first intermediate, formed before 250 micros, involved incorporation of Trp14 into the alpha-helix from a random coil. The frequency shift of the W3 band of Trp14 observed for this process was reproduced with a model peptide of the A helix when it forms the alpha-helix. In the second intermediate, formed around 1 ms after the start of refolding, the surroundings of both Trp7 and Trp14 were significantly hydrophobic, suggesting the formation of the hydrophobic core. In the third intermediate appearing around 3 ms, the hydrophobicity was relaxed to the same level as that of the pH 4 equilibrium intermediate, which was investigated in detail with the stationary state technique. The change from the third intermediate to the native state needs more time than 40 ms, while the appearance of the native spectrum after the mixing of the same solutions was confirmed separately. |
| Address |
School of Mathematical and Physical Sciences, The Graduate University for Advanced Studies, Myodaiji, Okazaki 444-8585, Japan |
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English |
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Abbreviated Series Title |
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Edition |
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0006-2960 |
ISBN |
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| Notes |
PMID:12022863 |
Approved |
no |
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Equine Behaviour @ team @ |
Serial |
3785 |
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