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McGreevy, P. D., & Rogers, L. J. (2005). Motor and sensory laterality in thoroughbred horses. Appl. Anim. Behav. Sci., 92(4), 337–352.
Abstract: We investigated lateralisation in horses because it is likely to be important in training and athletic performance. Thoroughbred horses (n = 106) were observed every 60 s for 2 h, when they were at pasture, and the position of the forelimbs in relation to one another was recorded. There was a population bias skewed to standing with the left forelimb advanced over the right (i.e. directional lateralisation). Using the first 50 observations, the distribution of preferences was 43 significantly left, 10 significantly right with 53 being non-significant (i.e. ambidextextrous). The strength of motor bias increased with age, suggesting maturation or an influence of training. The horses were also presented with an olfactory stimulus (stallion faeces) to score the tendency to use one nostril rather than the other. A significant preference to use the right nostril first was shown in horses under 4 years of age (n = 61) but not in older horses. Of the 157 horses tested for nostril bias, 76 had been assessed for motor bias and so were used for analysis of the relationship between laterality in the two modalities. There was no significant relationship between direction of foreleg motor bias and first nostril used, total number of inhalations or laterality index of nostril use. The absence of a correlation between laterality of nostril use and motor bias indicates that lateralisation of the equine brain occurs on at least two levels of neural organisation--sensory and motor--a finding that is consistent with other examples of lateralisation in species that have been examined in more detail.
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McGreevy, P. D., & Thomson, P. C. (2006). Differences in motor laterality between breeds of performance horse. Appl. Anim. Behav. Sci., 99(1-2), 183–190.
Abstract: This study examined the relationship between motor laterality in horses bred for different types of work and therefore different temperaments. Foreleg preference during grazing was measured in three populations of domestic horse, Thoroughbreds (TB, bred to race at the gallop), Standardbreds (SB, bred for pacing) and Quarter Horses (QH, in this case bred for so-called “cutting work” which involves manoeuvring individual cattle in and out of herds). With a one-sample t-test, TBs showed strong evidence of a left preference in motor laterality (P = 0.000), as did SBs (P = 0.002) but there was no convincing evidence for laterality in QH (P = 0.117). However, the increasing trend in left preference from QH to SBs then TBs was associated with increasing differences between individual horses within a breed. The overall preference (either left or right) increased with age (P = 0.008) and the rate of increase varied with breeds. The presence of a higher proportion of left-foreleg preferent individuals in TBs and SBs compared with QH may indicate that their training or selection (or both) has an effect on motor bias.
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Powell, D. M. (1999). Preliminary evaluation of porcine zona pellucida (PZP) immunocontraception for behavioral effects in feral horses (Equus caballus). J Appl Anim Welf Sci, 2(4), 321–335.
Abstract: Successful management of captive populations of wild animals requires effective control of reproduction. Contraception is one tool for controlling reproduction of animals in zoos; however, the options available to the animal manager are limited. Contraceptives vary in efficacy, reversibility, and side effects, and thus may not be suitable for widespread use. One consideration when selecting a contraceptive is its potential for side effects on behavior, especially given the fact that reproduction plays such a prominent role in the biology of any species. To date, there have been few evaluations of contraceptives for behavioral effects, and those that have been conducted have focused on hormone-based contraceptives. This study sought to evaluate a novel method of population control, immunocontraception, for behavioral effects in a population of feral horses. Porcine zona pellucida (PZP) immunocontraception prevents fertilization of ova and does not alter normal hormone secretion patterns. It therefore should leave the animal behaviorally intact in terms of reproductive behavior. The study examined the behavior of 43 sexually mature mares on Assateague Island during the 1997 breeding season and, with help from Earthwatch volunteers, collected observations over a 3-month period. The study found no significant differences between treated and untreated mares in general activity budget, aggression given or received, and spatial relationships relative to the stallion. These preliminary findings indicate that PZP contraception seems to have no acute behavioral effects on the behavior of individuals. The study findings also suggest that PZP could be a desirable and effective management tool for captive species in which social behavior plays an integral role in group dynamics. Analyses of group level effects and population level effects are continuing.
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Macfadden, B. J. (2005). Evolution. Fossil horses--evidence for evolution. Science, 307(5716), 1728–1730.
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Shanahan, S. (2003). Trailer loading stress in horses: behavioral and physiological effects of nonaversive training (TTEAM). J Appl Anim Welf Sci, 6(4), 263–274.
Abstract: Resistance in the horse to trailer loading is a common source of stress and injury to horses and their handlers. The objective of this study was to determine whether nonaversive training based on the Tellington-Touch Equine Awareness Method (TTEAM; Tellington-Jones &Bruns, 1988) would decrease loading time and reduce stress during loading for horses with a history of reluctance to load. Ten horses described by their owners as “problem loaders” were subjected to pretraining and posttraining assessments of loading. Each assessment involved two 7-min loading attempts during which heart rate and saliva cortisol were measured. The training consisted of six 30-min sessions over a 2-week period during which the horse and owner participated in basic leading exercises with obstacles simulating aspects of trailering. Assessment showed heart rate and saliva cortisol increased significantly during loading as compared to baseline (p <.001 and p <.05, respectively). Reassessment after training showed a decrease in loading time (p <.02), reduced heart rate during loading (p <.002), and reduced saliva cortisol as compared to pretraining assessments. Seven “good loaders” also were subject to loading assessment for physiological comparison. Increases in heart rate during loading were significantly higher in the good loaders (p <.001). Nonaversive training simulating aspects of loading may effectively reduce loading time and stress during loading for horses with a history of resistance to trailer loading.
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Budras, K. D., Scheibe, K., Patan, B., Streich, W. J., & Kim, K. (2001). Laminitis in Przewalski horses kept in a semireserve. J Vet Sci, 2(1), 1–7.
Abstract: Semireserves were created by the European Conservation Project for scientific research in preparation for reintroduction in the wilderness. They are defined as enclosures large enough to carry a group of Przewalski horses throughout the year without any additional feeding. The semireserve offers diverse opportunities for significant scientific research. As part of a general screening program, the hoof development in a group of Przewalski horses was investigated in the semireserve Schorfheide near Berlin. Since the foundation of this semireserve in 1992, veterinary treatment was not necessary with the exception of hoof trimming in two animals in 1993. However, major health problems were encountered in the spring of 1999, when three other mares showed signs of laminitis. The initial diagnosis by the authors and the local veterinary surgeon based on observation of behaviour, gait, stance, walk and trot of three mares whose initial weights were higher than those of the healthy mares. The initial diagnosis was confirmed by palpation and the occurrence of very deep horn rings on all hooves and a laminitic horn ring on the right front hoof of one mare. An adequate laminitic therapy was not possible under the conditions of a semireserve. The applied management aimed at two goals: 1. To reduce endotoxin production and acidosis in the horses by reducing the ingestion of carbohydrate rich food. 2. To reduce the mares level of activity and to prevent tearing of the suspensory apparatus of the coffin bone. To achieve these two goals it was decided to remove the three laminitic mares from the rich pasture in the main part of the semireserve and to confine them onto the poorer pasture of the small separately fenced area. All three affected mares had fully recovered from their laminitic condition. Prevention of grass laminitis can be achieved by the following measures: 1. Reduction in grass intake could be achieved by increasing the grazing pressure by an increase in stocking rate of the horses or mixed grazing with another species such as sheep. 2. A longer term solution to the problem may well be to sow specific varieties of grass with lower concentrations of water soluble carbohydrate.
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Krzak, W. E., Gonyou, H. W., & Lawrence, L. M. (1991). Wood chewing by stabled horses: diurnal pattern and effects of exercise. J. Anim Sci., 69(3), 1053–1058.
Abstract: Nine yearling horses, stabled in individual stalls, were used in a trial to determine the diurnal pattern of wood chewing and the effects of exercise on this behavior. The trial was a Latin square design conducted over three 2-wk periods during which each horse was exposed to each of the three following treatments: 1) no exercise (NE), 2) exercise after the morning feeding (AM), and 3) exercise in the afternoon (PM). Horses were fed a complete pelleted feed in the morning and both pelleted feed and long-stemmed hay in the afternoon. Exercise consisted of 45 min on a mechanical walker followed by 45 min in a paddock with bare soil. Each stall was equipped with two untreated spruce boards during each period for wood chewing. Wood chewing was evaluated by videotaping each horse for 22 h during each period, determining the weight and volume of the boards before and after each period, and by visual appraisal of the boards. Intake of trace mineralized salt was also measured. Wood chewing occurred primarily between 2200 and 1200. All measures of wood chewing were correlated when totals for the entire 6 wk were analyzed. When analysis was performed on 2-wk values, videotape results were not correlated with volume or weight loss of boards. Horses chewed more when on the NE treatment (511 s/d) than when on AM or PM (57 and 136 s/d, respectively; P less than .05). Salt intake tended to be greater for NE than for the other treatments (P less than .10).(ABSTRACT TRUNCATED AT 250 WORDS)
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Ralston, S. L. (1984). Controls of feeding in horses. J. Anim Sci., 59(5), 1354–1361.
Abstract: Members of the genus Equus are large, nonruminant herbivores. These animals utilize the products of both enzymatic digestion in the small intestine and bacterial fermentation (volatile fatty acids) in the cecum and large colon as sources of metabolizable energy. Equine animals rely primarily upon oropharyngeal and external stimuli to control the size and duration of an isolated meal. Meal frequency, however, is regulated by stimuli generated by the presence and (or) absorption of nutrients (sugars, fatty acids, protein) in both the large and small intestine plus metabolic cues reflecting body energy stores. The control of feeding in this species reflects its evolutionary development in an environment which selected for consumption of small, frequent meals of a variety of forages.
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McCall, C. A. (1990). A Review of Learning Behavior in Horses and its Application in Horse Training. J. Anim Sci., 68(1), 75–81.
Abstract: A literature review of the equine learning research conducted in the past 20 yr revealed that the purpose of most of the studies was to determine whether horses respond to learning situations in the same way that other animals do. The results indicated that horses can discriminate many different types of stimuli, and they learn through stimulus-response- reinforcement chains. Most equine learning studies have utilized learning tasks depending on primary positive reinforcement to get the horses to work the tests. Yet, the majority of horse trainers use negative reinforcement more often than primary positive reinforcement in their training procedures. Therefore, past research often did not have a direct application to training methods commonly utilized in the horse industry. Research also demonstrated that 1) early experiences of horses can affect learning ability later, 2) equine memory is efficient and 3) concentrating learning mals in long training sessions decreases equine learning efficiency. Many factors that might affect equine learning ability and be applicable to training practices in the horse industry have not been thoroughly investigated; for example, interactions between nutrition and learning and between exercise and learning, the use of negative and secondary reinforcements in horse training, and the horse's ability to make few initial errors compared to its ability to eliminate errors as training progresses all require investigation in future equine learning studies. N1 -
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Houpt, K. A., & Rudman, R. (2002). Foreword to special issue on equine behavior. Appl. Anim. Behav. Sci., 78(2-4), 83–85.
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