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Author  |
Vlasak, A.N. |
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Title |
Global and local spatial landmarks: their role during foraging by Columbian ground squirrels (Spermophilus columbianus) |
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Journal Article |
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Year |
2006 |
Publication |
Animal Cognition |
Abbreviated Journal |
Anim. Cogn. |
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Volume |
9 |
Issue |
1 |
Pages |
71-80 |
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Keywords |
Animals; Cues; Feeding Behavior/*psychology; Female; *Memory; Mental Recall; Orientation; Sciuridae/*psychology; *Space Perception; *Spatial Behavior |
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Abstract |
Locating food and refuge is essential for an animal's survival. However, little is known how mammals navigate under natural conditions and cope with given environmental constraints. In a series of six experiments, I investigated landmark-based navigation in free-ranging Columbian ground squirrels (Spermophilus columbianus). Squirrels were trained individually to find a baited platform within an array of nine identical platforms and artificial landmarks set up on their territories. After animals learned the location of the food platform in the array, the position of the latter with respect to local artificial, local natural, and global landmarks was manipulated, and the animal's ability to find the food platform was tested. When only positions of local artificial landmarks were changed, squirrels located food with high accuracy. When the location of the array relative to global landmarks was altered, food-finding accuracy decreased but remained significant. In the absence of known global landmarks, the presence of a familiar route and natural local landmarks resulted in significant but not highly accurate performance. Squirrels likely relied on multiple types of cues when orienting towards a food platform. Local landmarks were used only as a secondary mechanism of navigation, and were not attended to when a familiar route and known global landmarks were present. This study provided insights into landmark use by a wild mammal in a natural situation, and it demonstrated that an array of platforms can be employed to investigate landmark-based navigation under such conditions. |
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Biology Department, University of Pennsylvania, Philadelphia, PA 19104, USA. avlasak@sas.upenn.edu |
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1435-9448 |
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PMID:16163480 |
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Equine Behaviour @ team @ |
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2483 |
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Author |
Vlamings, P.H.J.M.; Uher, J.; Call, J. |
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Title |
How the great apes (Pan troglodytes, Pongo pygmaeus, Pan paniscus, and Gorilla gorilla) perform on the reversed contingency task: the effects of food quantity and food visibility |
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Journal Article |
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Year |
2006 |
Publication |
Journal of Experimental Psychology. Animal Behavior Processes |
Abbreviated Journal |
J Exp Psychol Anim Behav Process |
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Volume |
32 |
Issue |
1 |
Pages |
60-70 |
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Keywords |
Age Factors; Animals; Behavior, Animal/physiology; Cognition; Conditioning (Psychology); Female; *Food; Gorilla gorilla/*psychology; *Learning; Male; Pan paniscus/*psychology; Pan troglodytes/*psychology; Pongo pygmaeus/*psychology; *Visual Perception |
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S. T. Boysen and G. G. Berntson (1995) found that chimpanzees performed poorly on a reversed contingency task in which they had to point to the smaller of 2 food quantities to acquire the larger quantity. The authors compared the performance of 4 great ape species (Pan troglodytes, Pongo pygmaeus, Pan paniscus, and Gorilla gorilla) on the reversed contingency task while manipulating food quantity (0-4 or 1-4) and food visibility (visible pairs or covered pairs). Results showed no systematic species differences but large individual differences. Some individuals of each species were able to solve the reversed contingency task. Both quantity and visibility of the food items had a significant effect on performance. Subjects performed better when the disparity between quantities was smaller and the quantities were not directly visible. |
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Department of Developmental and Comparative Psychology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany. p.vlamings@psychology.unimaas.nl |
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0097-7403 |
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PMID:16435965 |
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Equine Behaviour @ team @ |
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2765 |
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Author |
Visser, E.K.; Van Reenen, C.G.; Rundgren, M.; Zetterqvist, M.; Morgan, K.; Blokhuis, H.J. |
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Title |
Responses of horses in behavioural tests correlate with temperament assessed by riders |
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Journal Article |
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Year |
2003 |
Publication |
Equine Veterinary Journal |
Abbreviated Journal |
Equine Vet J |
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Volume |
35 |
Issue |
2 |
Pages |
176-183 |
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Keywords |
Adult; Animals; *Behavior, Animal/physiology; Data Interpretation, Statistical; Female; *Handling (Psychology); Heart Rate/*physiology; Horses/physiology/*psychology; Humans; Male; Personality; Temperament/*physiology |
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REASONS FOR PERFORMING STUDY: Behavioural tests as well as observers' ratings have been used to study horses' temperament. However, the relationship between the ratings and the responses in behavioural tests has not yet been studied in detail. OBJECTIVES: The aim of the present study was to examine this relationship between ratings and responses. METHODS: Eighteen mature Swedish Warmblood horses were subjected to 2 behavioural tests, one relating to novelty (novel object test) and one to handling (handling test). Subsequently, 16 of these horses were ridden by 16 equally experienced students, having no former experience with the horses. Immediately after each ride, the students scored the horse for 10 temperamental traits using a line rating method. RESULTS: It was shown that for each temperamental trait all 16 riders agreed on the ranking of the horses (0.212<W<0.505, P < 0.001). CONCLUSIONS: Correlations between behavioural and heart rate variables in the behavioural tests revealed that horses with a high level of locomotion or much restlessness behaviour exhibited high mean heart rate and low heart rate variability. In particular, heart rate variables in the behavioural tests were found to correlate with riders' rating scores. Furthermore, the underlying components of the handling test, retrieved with a principal component analysis (PCA) correlated with riders' rating scores while the underlying components of the novel object test did not. POTENTIAL CLINICAL RELEVANCE: It is concluded that it is possible for a large panel of assessors to agree upon a horse's temperament and that objective measures from behavioural tests correlate significantly with temperamental traits assessed by a panel of assessors. |
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Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, PO Box 80.163, NL-3508 TD Utrecht, The Netherlands |
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0425-1644 |
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PMID:12638795 |
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1906 |
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Author |
Virga, V.; Houpt, K.A. |
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Title |
Prevalence of placentophagia in horses |
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Journal Article |
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Year |
2001 |
Publication |
Equine veterinary journal |
Abbreviated Journal |
Equine Vet J |
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33 |
Issue |
2 |
Pages |
208-210 |
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Keywords |
Animals; *Behavior, Animal; Colic/epidemiology/*veterinary; Exploratory Behavior; *Feeding Behavior; Female; Horse Diseases/*epidemiology; Horses; Incidence; New York/epidemiology; *Placenta; Postpartum Period; Pregnancy; Prevalence; Questionnaires |
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Animal Behavior Clinic, Cornell University Hospital for Animals, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853, USA |
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0425-1644 |
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PMID:11266073 |
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Call Number |
refbase @ user @ |
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31 |
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Author |
Virányi, Z.; Topál, J.; Miklósi, Á.; Csányi, V. |
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Title |
A nonverbal test of knowledge attribution: a comparative study on dogs and children |
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Journal Article |
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Year |
2006 |
Publication |
Animal Cognition |
Abbreviated Journal |
Anim. Cogn. |
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Volume |
9 |
Issue |
1 |
Pages |
13-26 |
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Keywords |
Animals; *Child Psychology; Child, Preschool; Cues; Dogs/*psychology; Female; Humans; Male; Nonverbal Communication; *Problem Solving; Species Specificity |
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The sensitivity of eleven pet dogs and eleven 2.5-year-old children to others' past perceptual access was tested for object-specificity in a playful, nonverbal task in which a human Helper's knowledge state regarding the whereabouts of a hidden toy and a stick (a tool necessary for getting the out-of-reach toy) was systematically manipulated. In the four experimental conditions the Helper either participated or was absent during hiding of the toy and the stick and therefore she knew the place(s) of (1) both the toy and the stick, (2) only the toy, (3) only the stick or (4) neither of them. The subjects observed the hiding processes, but they could not reach the objects, so they had to involve the Helper to retrieve the toy. The dogs were more inclined to signal the place of the toy in each condition and indicated the location of the stick only sporadically. However the children signalled both the location of the toy and that of the stick in those situations when the Helper had similar knowledge regarding the whereabouts of them (i.e. knew or ignored both of them), and in those conditions in which the Helper was ignorant of the whereabouts of only one object the children indicated the place of this object more often than that of the known one. At the same time however, both dogs and children signalled the place of the toy more frequently if the Helper had been absent during toy-hiding compared to those conditions when she had participated in the hiding. Although this behaviour appears to correspond with the Helper's knowledge state, even the subtle distinction made by the children can be interpreted without a casual understanding of knowledge-formation in others. |
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Department of Ethology, ELTE University Budapest, Pazmany P. setany 1/C H-1117, Hungary. zsofi.viranyi@freemail.hu |
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1435-9448 |
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PMID:15895261 |
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Call Number |
Equine Behaviour @ team @ |
Serial |
2486 |
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Author |
Villani, M.; Cairoli, F.; Kindahl, H.; Galeati, G.; Faustini, M.; Carluccio, A.; Veronesi, M.C. |
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Title |
Effects of mating on plasma concentrations of testosterone, cortisol, oestrone sulphate and 15-ketodihydro-PGF2alpha in stallions |
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Journal Article |
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Year |
2006 |
Publication |
Reproduction in Domestic Animals = Zuchthygiene |
Abbreviated Journal |
Reprod Domest Anim |
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Volume |
41 |
Issue |
6 |
Pages |
544-548 |
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Keywords |
Animals; Dinoprost/*analogs & derivatives/blood; Ejaculation/physiology; Estrone/*analogs & derivatives/blood; Horses/*blood/physiology; Hydrocortisone/*blood; Male; Sexual Behavior, Animal/*physiology; Testosterone/*blood |
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Very little information is available regarding the physiological mechanisms involved in the normal sexual activity in the stallion and, in particular, the endocrine control of reproduction is still not clearly understood. This experiment was designed to determine the short-term effect of sexual stimulation on plasma concentrations of testosterone, cortisol, oestrone sulphate and 15-ketodihydro-PGF(2alpha) in stallions. Semen samples were collected from 10 lighthorse stallions of proven fertility using a Missouri model artificial vagina. At the same time, blood samples were collected from the jugular vein with heparinized tubes, 20 and 10 min before oestrous mare exposure, at exposure and 10, 20, 30 min after dismounting. Testosterone concentrations showed a sharp rise 10 min after mating (p < 0.001), reached a plateau, and then showed a further increase 30 min after mating (p < 0.001). Cortisol concentrations increased 10 min after mating (p < 0.001) and remained at high levels in the subsequent samples taken. A peak of oestrone sulphate was observed 10 min after mating (p < 0.001). 15-Ketodihydro-PGF(2alpha) concentrations decreased rapidly at the moment of the exposure of the stallions to an oestrous mare (p < 0.05), returned to pre-mating concentrations and then decreased again 30 min after mating (p < 0.05). |
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Dipartimento di Scienze Cliniche Veterinarie, Sez. Clinica Ostetrica e Ginecologica Veterinaria, Milan, Italy |
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0936-6768 |
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PMID:17107515 |
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1855 |
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Author |
Vermeulen, A.D.; Evans, D.L. |
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Title |
Measurements of fitness in thoroughbred racehorses using field studies of heart rate and velocity with a global positioning system |
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Journal Article |
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Year |
2006 |
Publication |
Equine Veterinary Journal. Supplement |
Abbreviated Journal |
Equine Vet J Suppl |
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36 |
Pages |
113-117 |
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Keywords |
Animals; Female; Geographic Information Systems; Heart Rate/*physiology; Horses/*physiology; Male; Physical Conditioning, Animal/*physiology; Physical Fitness/*physiology; Running/physiology |
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REASONS FOR PERFORMING STUDY: Field based studies of changes in fitness are difficult to conduct in galloping Thoroughbreds. Measurements of heart rate (HR) and real time velocity with a global positioning system (GPS) could provide a method for routine field studies of fitness. OBJECTIVE: To investigate measurements of fitness in the field without using multiple, standardised steps of increasing velocity in the exercise test. METHODS: Twelve healthy 3- to 5-year-old Thoroughbreds were used in the study of reliability, and twelve 2-year-old Thoroughbreds in the investigation of the effect of training. Five second averages of velocity and HR were recorded during a typical fast exercise training session, using a GPS and Polar HR monitor. A standardised exercise test protocol was not used. Regression analyses using trot and gallop data were used to calculate velocities at HR of 200 beats/min (V200), and at maximal HR (VHRmax). Data were collected on consecutive 'fast' day training sessions to assess the reliability of measurements. The effect of training was investigated with fitness tests in weeks 2 and 6 of 'fast' training. Absolute and relative differences were calculated to evaluate reliability, and paired t tests were used to detect an effect of training. RESULTS: VHRmax, V200 and HRmax were reliable measurements of fitness, with mean differences of 2% or less. Reliability of VHRmax was not dependent on VHRmax. VHRmax and V200 both increased significantly with training (P<0.01), but there was no effect of training on HRmax. There were no significant changes in the slope or intercept of the regression equations after training. CONCLUSIONS: Velocity and HR measurements during field gallop exercise provided reliable measures of fitness which enabled a measurement of the response to training. POTENTIAL RELEVANCE: This approach offers a simple, noninvasive method for monitoring adaptations to training in the field. |
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Faculty of Veterinary Science, The University of Sydney, New South Wales 2006, Australia |
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PMID:17402404 |
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Equine Behaviour @ team @ |
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4013 |
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Author |
Verheyen, K.; Price, J.; Lanyon, L.; Wood, J. |
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Title |
Exercise distance and speed affect the risk of fracture in racehorses |
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Journal Article |
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Year |
2006 |
Publication |
Bone |
Abbreviated Journal |
Bone |
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39 |
Issue |
6 |
Pages |
1322-1330 |
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Keywords |
Animals; Case-Control Studies; Cohort Studies; England; Exertion; Female; Fractures, Bone/etiology/*veterinary; Horse Diseases/*etiology; Horses/*injuries; Male; Physical Conditioning, Animal/adverse effects/methods; Poisson Distribution; Prospective Studies; Regression Analysis; Risk Factors; Running/injuries/physiology |
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In order to gain insight into those training regimens that can minimise the risk of fracture in athletic populations, we conducted a large epidemiological study in racehorses. Thoroughbred racehorses provide a suitable model for studying fracture development and exercise-related risk factors in physically active populations. They represent a homogeneous population, undertaking intensive exercise programmes that are sufficiently heterogeneous to determine those factors that influence injury risk. Daily exercise information was recorded for a cohort of 1178 thoroughbreds that were monitored for up to 2 years. A total of 148 exercise-induced fractures occurred in the study population. Results from a nested case-control study showed a strong interactive effect of exercise distances at different speeds on fracture risk. Horses that exceeded 44 km at canter (< or =14 m/s) and 6 km at gallop (>14 m/s) in a 30-day period were at particularly increased risk of fracture. These distances equate to ca. 7700 bone loading cycles at canter and 880 loading cycles at gallop. Fifty-six fractures occurred in the subset of study horses that were followed since entering training as yearlings, when skeletally immature (n = 335). Cohort analysis of this data set showed that, in previously untrained bones, accumulation of canter exercise increased the risk of fracture (P < or = 0.01), whereas accumulation of high-speed gallop exercise had a protective effect (P < 0.01). However, increasing distances at canter and gallop in short time periods (up to one month) were associated with an increasing fracture risk. All training exercise involves a balance between the risk of fracture inherent in exposure to loading and the beneficial effect that loading has by stimulating bone cells to produce a more robust architecture. Results from our study provide important epidemiological evidence of the effects of physical exercise on bone adaptation and injury risk and can be used to inform the design of safer exercise regimens in physically active populations. |
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Epidemiology Unit, Animal Health Trust, Newmarket, United Kingdom. kverheyen@rvc.ac.uk |
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8756-3282 |
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PMID:16926125 |
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Equine Behaviour @ team @ |
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4030 |
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Author |
van Heel, M.C.V.; Kroekenstoel, A.M.; van Dierendonck, M.C.; van Weeren, P.R.; Back, W. |
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Title |
Uneven feet in a foal may develop as a consequence of lateral grazing behaviour induced by conformational traits |
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Journal Article |
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Year |
2006 |
Publication |
Equine veterinary journal |
Abbreviated Journal |
Equine. Vet. J. |
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Volume |
38 |
Issue |
7 |
Pages |
646-651 |
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Aging/*physiology; Animals; Animals, Newborn/anatomy & histology/growth & development/physiology; Feeding Behavior/*physiology; Female; Forelimb/*anatomy & histology/*physiology; *Horses/anatomy & histology/growth & development/physiology; Male |
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REASONS FOR PERFORMING STUDY: Conformational traits are important in breeding, since they may be indicative for performance ability and susceptibility to injuries. OBJECTIVES: To study whether certain desired conformational traits of foals are related to lateralised behaviour while foraging and to the development of uneven feet. METHODS: Twenty-four Warmblood foals, born and raised at the same location, were studied for a year. Foraging behaviour was observed by means of weekly 10 min scan-sampling for 8 h. A preference test (PT) was developed to serve as a standardised tool to determine laterality. The foals were evaluated at age 3, 15, 27 and 55 weeks. The PT and distal limb conformation were used to study the relation between overall body conformation, laterality and the development of uneven feet. Pressure measurements were used to determine the loading patterns under the feet. RESULTS: About 50% of the foals developed a significant preference to protract the same limb systematically while grazing, which resulted in uneven feet and subsequently uneven loading patterns. Foals with relatively long limbs and small heads were predisposed to develop laterality and, consequently unevenness. CONCLUSIONS: Conformational traits may stimulate the development of laterality and therefore indirectly cause uneven feet. |
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Derona Equine Performance Laboratory, Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 12, NL-3584 CM Utrecht, The Netherlands |
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0425-1644 |
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PMID:17228580 |
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1774 |
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Author |
van der Willigen, R.F.; Frost, B.J.; Wagner, H. |
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How owls structure visual information |
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Journal Article |
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Year |
2003 |
Publication |
Animal Cognition |
Abbreviated Journal |
Anim. Cogn. |
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6 |
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1 |
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39-55 |
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Animals; *Cognition; Depth Perception; Discrimination Learning; Female; Male; *Strigiformes; *Visual Perception |
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Abstract |
Recent studies on perceptual organization in humans claim that the ability to represent a visual scene as a set of coherent surfaces is of central importance for visual cognition. We examined whether this surface representation hypothesis generalizes to a non-mammalian species, the barn owl ( Tyto alba). Discrimination transfer combined with random-dot stimuli provided the appropriate means for a series of two behavioural experiments with the specific aims of (1) obtaining psychophysical measurements of figure-ground segmentation in the owl, and (2) determining the nature of the information involved. In experiment 1, two owls were trained to indicate the presence or absence of a central planar surface (figure) among a larger region of random dots (ground) based on differences in texture. Without additional training, the owls could make the same discrimination when figure and ground had reversed luminance, or were camouflaged by the use of uniformly textured random-dot stereograms. In the latter case, the figure stands out in depth from the ground when positional differences of the figure in two retinal images are combined (binocular disparity). In experiment 2, two new owls were trained to distinguish three-dimensional objects from holes using random-dot kinematograms. These birds could make the same discrimination when information on surface segmentation was unexpectedly switched from relative motion to half-occlusion. In the latter case, stereograms were used that provide the impression of stratified surfaces to humans by giving unpairable image features to the eyes. The ability to use image features such as texture, binocular disparity, relative motion, and half-occlusion interchangeably to determine figure-ground relationships suggests that in owls, as in humans, the structuring of the visual scene critically depends on how indirect image information (depth order, occlusion contours) is allocated between different surfaces. |
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Institut fur Biologie II, RWTH Aachen, Kopernikusstrasse 16, 52074, Aachen, Germany. willigen@bio2.rwth-aachen.de |
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English |
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1435-9448 |
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PMID:12658534 |
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Equine Behaviour @ team @ |
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2582 |
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