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Author Carroll, J.; Murphy, C.J.; Neitz, M.; Hoeve, J.N.; Neitz, J. doi  openurl
  Title Photopigment basis for dichromatic color vision in the horse Type Journal Article
  Year 2001 Publication Journal of Vision Abbreviated Journal J Vis  
  Volume 1 Issue 2 Pages 80-87  
  Keywords Adaptation, Physiological; Animals; Color Perception/*physiology; Cones (Retina)/chemistry/*physiology; Electroretinography; Horses/*physiology; Photic Stimulation; Phototransduction/physiology; Retinal Pigments/analysis/*physiology; Visual Perception/physiology  
  Abstract Horses, like other ungulates, are active in the day, at dusk, dawn, and night; and, they have eyes designed to have both high sensitivity for vision in dim light and good visual acuity under higher light levels (Walls, 1942). Typically, daytime activity is associated with the presence of multiple cone classes and color-vision capacity (Jacobs, 1993). Previous studies in other ungulates, such as pigs, goats, cows, sheep and deer, have shown that they have two spectrally different cone types, and hence, at least the photopigment basis for dichromatic color vision (Neitz & Jacobs, 1989; Jacobs, Deegan II, Neitz, Murphy, Miller, & Marchinton, 1994; Jacobs, Deegan II, & Neitz, 1998). Here, electroretinogram flicker photometry was used to measure the spectral sensitivities of the cones in the domestic horse (Equus caballus). Two distinct spectral mechanisms were identified and are consistent with the presence of a short-wavelength-sensitive (S) and a middle-to-long-wavelength-sensitive (M/L) cone. The spectral sensitivity of the S cone was estimated to have a peak of 428 nm, while the M/L cone had a peak of 539 nm. These two cone types would provide the basis for dichromatic color vision consistent with recent results from behavioral testing of horses (Macuda & Timney, 1999; Macuda & Timney, 2000; Timney & Macuda, 2001). The spectral peak of the M/L cone photopigment measured here, in vivo, is similar to that obtained when the gene was sequenced, cloned, and expressed in vitro (Yokoyama & Radlwimmer, 1999). Of the ungulates that have been studied to date, all have the photopigment basis for dichromatic color vision; however, they differ considerably from one another in the spectral tuning of their cone pigments. These differences may represent adaptations to the different visual requirements of different species.  
  Address Department of Cell Biology, Neurobiology & Anatomy, Medical College of Wisconsin, Milwaukee, WI, USA  
  Corporate Author Thesis  
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  Language English Summary Language Original Title  
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  Series Volume Series Issue (down) Edition  
  ISSN 1534-7362 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:12678603 Approved no  
  Call Number Equine Behaviour @ team @ Serial 4060  
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Author Berger, J. openurl 
  Title Induced abortion and social factors in wild horses Type Journal Article
  Year 1983 Publication Nature Abbreviated Journal Nature  
  Volume 303 Issue 5912 Pages 59-61  
  Keywords Abortion, Induced/*veterinary; Abortion, Veterinary/*etiology; Aggression/physiology; Animals; Evolution; Female; Horses/*physiology; Humans; Pregnancy; Sexual Behavior, Animal/*physiology  
  Abstract Much evidence now suggests that the postnatal killing of young in primates and carnivores, and induced abortions in some rodents, are evolved traits exerting strong selective pressures on adult male and female behaviour. Among ungulates it is perplexing that either no species have developed convergent tactics or that these behaviours are not reported, especially as ungulates have social systems similar to those of members of the above groups. Only in captive horses (Equus caballus) has infant killing been reported. It has been estimated that 40,000 wild horses live in remote areas of the Great Basin Desert of North America (US Department of Interior (Bureau of Land Management), unpublished report), where they occur in harems (females and young) defended by males. Here I present evidence that, rather than killing infants directly, invading males induce abortions in females unprotected by their resident stallions and these females are then inseminated by the new males.  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue (down) Edition  
  ISSN 0028-0836 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:6682487 Approved no  
  Call Number Equine Behaviour @ team @ Serial 4365  
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Author Kaseda, Y.; Ogawa, H.; Khalil, A.M. url  doi
openurl 
  Title Causes of natal dispersal and emigration and their effects on harem formation in Misaki feral horses Type Journal Article
  Year 1997 Publication Equine Veterinary Journal Abbreviated Journal Equine Vet J  
  Volume 29 Issue 4 Pages 262-266  
  Keywords Age Factors; Animal Migration; Animals; Animals, Wild; *Behavior, Animal/physiology; Female; Horses/*physiology/psychology; Male; Reproduction; Seasons; Sexual Behavior, Animal; *Social Behavior  
  Abstract Misaki feral horses were separated into 2 herds and the difference between dispersal from natal group (natal dispersal) and dispersal from natal area (natal emigration) was studied. The causes of dispersal and emigration and their effects on harem formation were studied 1979-1994. The number of horses ranged from 73 (mature males: 8, mature females: 26, young males: 8, young females: 3, colt foals: 6, filly foals: 10 and geldings: 12) in 1979 and 86 (mature males: 14, mature females: 37, young males: 12, young females: 7, colt foals: 5, filly foals: 7 and geldings: 4) in 1994 when the present study ended. All 29 males which survived to age 4 years and 58 females which survived to age 3 years left their natal or mother groups at age one to 3. Seventeen of 22 dispersing males and 29 of 39 dispersing females left their natal groups around the birth of their siblings and significant correlations were found between natal dispersal and birth of a sibling. The number of emigrating young males correlated negatively and significantly with the total number of young males in another herd and the number of emigrating young females correlated positively and significantly with the total number of young females in the natal herd. All 13 emigrating stallions which survived to age 5 years formed stable harem groups and a significant correlation was found between natal emigration and harem formation. Twenty-three of 35 resident mares formed stable consort relations with harem stallions and a significant correlation was found between residence and formation of stable consort relations.  
  Address Faculty of Agriculture, Miyazaki University, Miyazaki-shi, 889-21, Japan  
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  Language English Summary Language Original Title  
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  Series Volume Series Issue (down) Edition  
  ISSN 0425-1644 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:15338905 Approved no  
  Call Number Equine Behaviour @ team @ Serial 4630  
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Author De Boyer Des Roches, A.; Richard-Yris, M.-A.; Henry, S.; Ezzaouia, M.; Hausberger, M. url  doi
openurl 
  Title Laterality and emotions: visual laterality in the domestic horse (Equus caballus) differs with objects' emotional value Type Journal Article
  Year 2008 Publication Physiology & Behavior Abbreviated Journal Physiol. Behav.  
  Volume 94 Issue 3 Pages 487-490  
  Keywords Animals; Animals, Newborn; Behavior, Animal/physiology; Dominance, Ocular/*physiology; *Emotions; Exploratory Behavior/physiology; Female; Horses/*physiology; Olfactory Pathways/physiology; Pattern Recognition, Visual/*physiology; Photic Stimulation; Pregnancy; Statistics, Nonparametric; Visual Fields/physiology  
  Abstract Lateralization of emotions has received great attention in the last decades, both in humans and animals, but little interest has been given to side bias in perceptual processing. Here, we investigated the influence of the emotional valence of stimuli on visual and olfactory explorations by horses, a large mammalian species with two large monocular visual fields and almost complete decussation of optic fibres. We confronted 38 Arab mares to three objects with either a positive, negative or neutral emotional valence (novel object). The results revealed a gradient of exploration of the 3 objects according to their emotional value and a clear asymmetry in visual exploration. When exploring the novel object, mares used preferentially their right eyes, while they showed a slight tendency to use their left eyes for the negative object. No asymmetry was evidenced for the object with the positive valence. A trend for an asymmetry in olfactory investigation was also observed. Our data confirm the role of the left hemisphere in assessing novelty in horses like in many vertebrate species and the possible role of the right hemisphere in processing negative emotional responses. Our findings also suggest the importance of both hemispheres in the processing positive emotions. This study is, to our knowledge, the first to demonstrate clearly that the emotional valence of a stimulus induces a specific visual lateralization pattern.  
  Address UMR CNRS 6552 Ethologie-Evolution-Ecologie, Universite de Rennes 1, Avenue du General Leclerc, Campus de Beaulieu, F-35042 Rennes Cedex, France. a.de-boyer@wanadoo.fr  
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  Language English Summary Language Original Title  
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  Series Volume Series Issue (down) Edition  
  ISSN 0031-9384 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:18455205 Approved no  
  Call Number Equine Behaviour @ team @ Serial 4762  
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Author Hedberg, Y.; Dalin, A.-M.; Ohagen, P.; Holm, K.R.; Kindahl, H. url  doi
openurl 
  Title Effect of oestrous-cycle stage on the response of mares in a novel object test and isolation test Type Journal Article
  Year 2005 Publication Reproduction in Domestic Animals = Zuchthygiene Abbreviated Journal Reprod Domest Anim  
  Volume 40 Issue 5 Pages 480-488  
  Keywords Animals; Behavior, Animal/*physiology; Cross-Over Studies; Diestrus/*physiology; Estrus/*physiology; Female; Heart Rate/*physiology; Horses/*physiology; Questionnaires  
  Abstract In various species, sex, hormonal treatments and oestrous-cycle stage have been shown to affect the animal's response in behavioural tests. Few such studies have been performed in the horse. The main aim of the present study was to investigate whether oestrous-cycle stage affects mares' response to a novel object test and isolation test and, in part, to study whether mares, assumed to suffer from oestrous-related behavioural problems, respond differently in these tests when compared with controls. Twelve mares were tested twice, in oestrus and dioestrus, in a crossover design. Seven behavioural and two heart rate variables were measured for the novel object test and two heart rate variables for the isolation test. Oestrous-cycle stage and whether a mare was classified as a 'problem' mare did not affect the mare's response. However, test order, i.e. the cycle stage a mare was tested in first, affected its reaction. This effect could partly be explained by significant differences between test occasions 1 and 2 in three behavioural variables and one heart rate variable (p < 0.05) in the novel object test. The mares explored the novel object more and had a higher mean heart rate in the first test. Exploring the novel object more could largely be attributed to those mares tested in dioestrus first, perhaps indicating that the mares in oestrus were less receptive to the novel object. The reason for the differences between test occasions could be an effect of learning or habituation.  
  Address Division of Comparative Reproduction, Obstetrics and Udder Health, Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden. ylva.hedberg@kv.slu.se  
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  Language English Summary Language Original Title  
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  Series Volume Series Issue (down) Edition  
  ISSN 0936-6768 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:16149956 Approved no  
  Call Number Equine Behaviour @ team @ Serial 5170  
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Author Heffner, R.S.; Heffner, H.E. url  openurl
  Title Localization of tones by horses: use of binaural cues and the role of the superior olivary complex Type Journal Article
  Year 1986 Publication Behavioral Neuroscience Abbreviated Journal Behav Neurosci  
  Volume 100 Issue 1 Pages 93-103  
  Keywords Animals; Auditory Pathways/physiology; Auditory Perception/*physiology; Avoidance Learning/physiology; Brain Mapping; Electroshock; Female; Horses/*physiology; Male; Olivary Nucleus/anatomy & histology/*physiology; Orientation/physiology; Pitch Perception/physiology; Sound Localization/*physiology  
  Abstract The ability of horses to use binaural time and intensity difference cues to localize sound was assessed in free-field localization tests by using pure tones. The animals were required to discriminate the locus of a single tone pip ranging in frequency from 250 Hz to 25 kHz emitted by loudspeakers located 30 degrees to the left and right of the animals' midline (60 degrees total separation). Three animals were tested with a two-choice procedure; 2 additional animals were tested with a conditioned avoidance procedure. All 5 animals were able to localize 250 Hz, 500 Hz, and 1 kHz but were completely unable to localize 2 kHz and above. Because the frequency of ambiguity for the binaural phase cue delta phi for horses in this test was calculated to be 1.5 kHz, these results indicate that horses can use binaural time differences in the form of delta phi but are unable to use binaural intensity differences. This finding was supported by an unconditioned orientation test involving 4 additional horses, which showed that horses correctly orient to a 500-Hz tone pip but not to an 8-kHz tone pip. Analysis of the superior olivary complex, the brain stem nucleus at which binaural interactions first take place, reveals that the lateral superior olive (LSO) is relatively small in the horse and lacks the laminar arrangement of bipolar cells characteristic of the LSO of most mammals that can use binaural delta I.  
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  Language English Summary Language Original Title  
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  Series Volume Series Issue (down) Edition  
  ISSN 0735-7044 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:3954885 Approved no  
  Call Number Equine Behaviour @ team @ Serial 5634  
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Author Houpt, K.A. openurl 
  Title Why horse behaviour is important to the equine clinician Type Journal Article
  Year 2006 Publication Equine veterinary journal Abbreviated Journal Equine Vet J  
  Volume 38 Issue 5 Pages 386-387  
  Keywords Accidents, Occupational/prevention & control; Aggression; Animals; *Behavior, Animal/physiology; Clinical Competence; Fear; Horses/*physiology; Humans; Veterinarians/psychology; Veterinary Medicine/*standards  
  Abstract  
  Address Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853-6401, USA  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue (down) Edition  
  ISSN 0425-1644 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:16986596 Approved no  
  Call Number refbase @ user @ Serial 30  
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Author Houpt, K.A.; Eggleston, A.; Kunkle, K.; Houpt, T.R. openurl 
  Title Effect of water restriction on equine behaviour and physiology Type Journal Article
  Year 2000 Publication Equine veterinary journal Abbreviated Journal Equine Vet J  
  Volume 32 Issue 4 Pages 341-344  
  Keywords Animals; *Behavior, Animal; Blood Proteins/analysis; Energy Intake; Female; Horse Diseases/physiopathology; Horses/*physiology; Osmolar Concentration; Pregnancy; Stress/veterinary; Video Recording; Water Deprivation/*physiology  
  Abstract Six pregnant mares were used to determine what level of water restriction causes physiological and/or behavioural changes indicative of stress. Nonlegume hay was fed ad libitum. During the first week of restriction, 5 l water/100 kg bwt was available, during the second week 4 l/100 kg bwt and, during the third week, 3 l/100 kg bwt. Ad libitum water intake was 6.9 l/100 kg bwt; at 3 l/100 kg bwt water intake was 42% of this. Daily hay intake fell significantly with increasing water restriction from 12.9 +/- 0.75 kg to 8.3 +/- 0.54 kg; bodyweight fell significantly for a total loss of 48.5 +/- 8.3 kg in 3 weeks. Daily blood samples were analysed; osmolality rose significantly with increasing water restriction from 282 +/- 0.7 mosmols/kg to 293.3 +/- 0.8 mosmols/kg bwt, but plasma protein and PCV did not change significantly. Cortisol concentrations fell from 8.1 ng/ml to 6.4 ng/ml over the 3 week period. Aldosterone fell from 211.3 +/- 74.2 pg/ml to 92.5 +/- 27.5 pg/ml at the end of the first week. The behaviour of 4 of the 6 mares was recorded 24 h/day for the duration of the study. The only significant difference was in time spent eating, which decreased with increasing water restriction from 46 +/- 3% to 30 +/- 3%. It is concluded that water restriction to 4 l/100 kg bwt dehydrates pregnant mares and may diminish their welfare, but is not life- or pregnancy-threatening.  
  Address Department of Physiology, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853-6401, USA  
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  Series Volume Series Issue (down) Edition  
  ISSN 0425-1644 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:10952384 Approved no  
  Call Number refbase @ user @ Serial 32  
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Author Houpt, K.A. openurl 
  Title Ingestive behavior Type Journal Article
  Year 1990 Publication The Veterinary clinics of North America. Equine practice Abbreviated Journal Vet Clin North Am Equine Pract  
  Volume 6 Issue 2 Pages 319-337  
  Keywords Animals; Eating/*physiology; Feeding Behavior/*physiology; Horses/*physiology  
  Abstract In summary, horses spend 60% or more of their time eating when grazing or when feed is available free choice. Grasses are their preferred food, but they supplement the grass with herbs and woody plants. Sweetened mixtures of oats and corn are the most preferred concentrate. Horses can increase or decrease the time spent eating and amount eaten to maintain caloric intake. Their intake is stimulated by drugs such as diazepam and by the presence of other horses. Horses stop eating when gastric osmolality increases; increases in plasma osmolality, protein, and glucose accompany digestion. Foals eat several times an hour and begin sampling solid food at the same time that their dam is eating. Several areas of particular importance to the equine industry have not been investigated. These areas include the effect of exercise on short- and long-term food intake and the influence of reproductive state on the feeding of mares.  
  Address Department of Physiology, New York State College of Veterinary Medicine, Cornell University, Ithaca  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue (down) Edition  
  ISSN 0749-0739 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:2202495 Approved no  
  Call Number refbase @ user @ Serial 42  
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Author Shaw, E.B.; Houpt, K.A.; Holmes, D.F. openurl 
  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 Department of Physiology, New York State College of Veterinary Medicine, Cornell University, Ithaca 14853  
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  Language English Summary Language Original Title  
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  Series Volume Series Issue (down) Edition  
  ISSN 0425-1644 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:3402416 Approved no  
  Call Number refbase @ user @ Serial 46  
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