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Byström, A., Clayton, H. M., Hernlund, E., Rhodin, M., & Egenvall, A. (2020). Equestrian and biomechanical perspectives on laterality in the horse. Comp. Exerc. Physiol., 16(1), 35–45.
Abstract: It has been suggested that one of the underlying causes of asymmetrical performance and left/right bias in sound riding horses is laterality originating in the cerebral cortices described in many species. The aim of this paper is to review the published evidence for inherent biomechanical laterality in horses deemed to be clinically sound and relate these findings to descriptions of sidedness in equestrian texts. There are no established criteria to determine if a horse is left or right dominant but the preferred limb has been defined as the forelimb that is more frequently protracted during stance and when grazing. Findings on left-right differences in forelimb hoof shape and front hoof angles have been linked to asymmetric forelimb ground reaction forces. Asymmetries interpreted as motor laterality have been found among foals and unhandled youngsters, and the consistency or extent of asymmetries seems to increase with age. Expressions of laterality also vary with breed, sex, training and handling, stress, and body shape but there are no studies of the possible link between laterality and lameness. In a recent study of a group of seven dressage horses, a movement pattern in many ways similar to descriptions of sidedness in the equestrian literature, e.g. one hind limb being more protracted and placed more laterally than the other, has been documented. The role of innate laterality versus painful conditions, training, human handedness and simply habit remains to be determined. Understanding the biomechanical manifestations of laterality in healthy horses, including individual variation, would yield a potential basis for how laterality should be taken into account in relation to training/riding and rehabilitation of lameness.
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Gardner, E. L., & Engel, D. R. (1971). Imitational and social facilitatory aspects of observational learning in the laboratory rat. Psychon. Sci., 25(1), 5–6.
Abstract: Rats acquired a food-motivated leverpressing response by “observational learning” or by trial-and-error learning under conditions of social facilitation or isolation. Both the observational learning and social facilitation Ss learned faster than did the isolated trial-and-error Ss. There was no difference in speed of learning between the observational learning and social facilitation groups. It is suggested that some previous studies purporting to demonstrate observational learning may have demonstrated socially facilitated trial-and-error learning instead.
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Bonin, S. J., Clayton, H. M., Lanovaz, J. L., & Johnston, T. (2007). Comparison of mandibular motion in horses chewing hay and pellets. Equine Vet. J., 39(3), 258–262.
Abstract: Summary Reasons for performing study: Previous studies have suggested that temporomandibular joint (TMJ) kinematics depend on the type of food being masticated, but accurate measurements of TMJ motion in horses chewing different feeds have not been published. Hypothesis: The temporomandibular joint has a larger range of motion when horses chew hay compared to pellets. Methods: An optical motion capture system was used to track skin markers on the skull and mandible of 7 horses as they chewed hay and pellets. A virtual marker was created on the midline between the mandibles at the level of the 4th premolar teeth to represent the overall motion of the mandible relative to the skull during the chewing cycle. Results: Frequency of the chewing cycles was lower for hay than for pellets. Excursions of the virtual mandibular marker were significantly larger in all 3 directions when chewing hay compared to pellets. The mean velocity of the virtual mandibular marker during the chewing cycle was the same when chewing the 2 feeds. Conclusions: The range of mediolateral displacement of the mandible was sufficient to give full occlusal contact of the upper and lower dental arcades when chewing hay but not when chewing pellets. Potential relevance: These findings support the suggestion that horses receiving a diet high in concentrate feeds may require more frequent dental prophylactic examinations and treatments to avoid the development of dental irregularities associated with smaller mandibular excursions during chewing.
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Davies, H. M. S., & Merritt, J. S. (2004). Surface strains around the midshaft of the third metacarpal bone during turning. Equine Veterinary Journal, 36(8), 689–692.
Abstract: Summary Reasons for performing study: Bone strains quantify skeletal effects of specific exercise and hence assist in designing training programmes to avoid bone injury. Objective: To test whether compressive strains increase on the lateral surface of the inside third metacarpal bone (McIII) and the medial surface of the outside McIII in a turn. Methods: Rosette strain gauges on dorsal, medial and lateral surfaces of the midshaft of the left McIII in 2 Thoroughbred geldings were recorded simultaneously during turning at the walk on a bitumen surface. Results: Medial surface: Compression peaks were larger in the outside limb. Tension peaks were larger in the inside limb and in a tighter turn. On the lateral surface compression and tension peaks were larger on the inside limb, which showed the largest recorded strains (compression of -1400 microstrains). Dorsal compression strains were larger on the outside limb and on a larger circle. Tensile strains were similar in both directions and larger on a larger circle. Conclusions: Compressive strains increased on the lateral surface of the inside McIII and medial surface of the outside McIII in a turn. Potential relevance: Slow-speed turning exercise may be sufficient to maintain bone mechanical characteristics in the inside limb lateral McIII cortex. Further work is needed to confirm these findings and to determine whether faster gaits and/or tighter turns are sufficient to cause bone modelling levels of strain in the medial and lateral McIII cortex.
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Hartmann, E., Bøe, K. E., Jørgensen, G. H. M., Mejdell, C. M., & Dahlborn, K. (2017). Management of horses with focus on blanketing and clipping practices reported by members of the Swedish and Norwegian equestrian community1. J Anim Sci, 95(3), 1104–1117.
Abstract: Limited information is available on the extent to which blankets are used on horses and the owners' reasoning behind clipping the horse's coat. Research on the effects of those practices on horse welfare is scarce but results indicate that blanketing and clipping may not be necessary from the horse's perspective and can interfere with the horse's thermoregulatory capacities. Therefore, this survey collected robust, quantitative data on the housing routines and management of horses with focus on blanketing and clipping practices as reported by members of the Swedish and Norwegian equestrian community. Horse owners were approached via an online survey, which was distributed to equestrian organizations and social media. Data from 4,122 Swedish and 2,075 Norwegian respondents were collected, of which 91 and 84% of respondents, respectively, reported using blankets on horses during turnout. Almost all respondents owning warmblood riding horses used blankets outdoors (97% in Sweden and 96% in Norway) whereas owners with Icelandic horses and coldblood riding horses used blankets significantly less (P < 0.05). Blankets were mainly used during rainy, cold, or windy weather conditions and in ambient temperatures of 10°C and below. The horse's coat was clipped by 67% of respondents in Sweden and 35% of Norwegian respondents whereby owners with warmblood horses and horses primarily used for dressage and competition reported clipping the coat most frequently. In contrast to scientific results indicating that recovery time after exercise increases with blankets and that clipped horses have a greater heat loss capacity, only around 50% of respondents agreed to these statements. This indicates that evidence-based information on all aspects of blanketing and clipping has not yet been widely distributed in practice. More research is encouraged, specifically looking at the effect of blankets on sweaty horses being turned out after intense physical exercise and the effect of blankets on social interactions such as mutual grooming. Future efforts should be tailored to disseminate knowledge more efficiently, which can ultimately stimulate thoughtful decision-making by horse owners concerning the use of blankets and clipping the horse's coat.
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Goetsch, A. L., Gipson, T. A., Askar, A. R., & Puchala, R. (2010). Feeding behavior of goats. J Anim Sci, 88.
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Huron, D. (2010). Voice Denumerability of Homogeneous Timbres. Music Percept Interdiscip J, 6.
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Harrington, F. H., & Mech, L. D. (1982). An analysis of howling response parameters useful for wolf pack censusing. J Wildl Manag, 46.
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Burch, J. W., Layne, G. A., Follmann, E. H., & Rexstad, E. A. (2005). Evaluation of Wolf Density Estimation from Radiotelemetry Data. Wildl Soc Bull, 33.
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Mladenoff, D. J., Sickley, T. A., & Wydeven, A. P. (1999). Predicting gray wolf landscape recolonization: logistic regression models vs. new field data. Ecol Appl, 9.
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