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 sub-optimal 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 horses? 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.

Abstract: Each of 104 horses and ponies was approached for catching at pasture by the same human handler in a standard manner, either maintaining human-to-animal eye contact (EC+; n = 51) or avoiding eye contact (EC-; n = 53). A subset of 74 of these subjects were reevaluated 3 weeks later under similar standard conditions except with the eye contact condition opposite to that used in the first round. Nonparametric statistical methods were used to evaluate between subjects (round 1, n = 104) and within subjects (rounds 1 and 2, n = 74) comparisons of successful or unsuccessful catching outcome with EC+ and EC-. Catching outcomes were similar with eye contact condition. Although this study represents a single handler at one study site, results suggest that human-to-horse eye contact may not be an important influence on catching pastured horses. Certainly, further work is needed to better understand the role of eye contact in horse handling.

Abstract: Horses with severe and deep lacerations are represented by ten cases in which treatment emphasized the use of bovine collagen preparations to promote controlled second-degree repair. Traumatized areas were tarsal, metatarsal, neck, forearm, metacarpal and pastern. Wound size changes were recorded. Depending on the wound type, the site was treated with antibiotic-steroid ointment, organic acid cream, sterile collagen particles, suspension or dressings protected by hydrogel dressing, non-adherent pads, occlusive skin dressings, roll gauze and elastic tape. In three cases, a fiberglas cast was applied over a hind leg wound and lacerated tendon for stability. When controlled granulation of the deeper wounds reached skin level, the area often was stabilized by only cyanoacrylate spray. As these cases presented a wide range of trauma each with a unique history, healing rates were based on initial measurements. An overall progression of wound reduction occurred at a predictable rate. The exogenous collagen formulations were used to stimulate controlled granulation, ie. to “jump start” the healing process. Collagen particles, suspension or dressings were packed into depressions, placed under suture lines, secured over abraded tissue, and placed under protective bandage or cast. To further evaluate the use of cyanoacrylate tissue spray in wound treatments, an additional ten cases are presented. The variety of wounds were produced experimentally in Center-owned ponies or provided as clinical cases. Wound size changes and healing progress were recorded. Wounds occurred on the neck, abdomen, metacarpal, metatarsal, fetlock and pastern areas. Depending on wound type, the site was treated with cyanoacrylate only; or treated as above until controlled granulation attained skin level. In one case punch grafts of skin were transferred from one foreleg to the opposite with the horse standing. Cyanoacrylate spray provided a water proof barrier protecting the wound from dirt, debris and insects as well as stabilizing full-thickness skin lacerations by bridging normal to traumatized skin allowing uninterrupted granulation and epithelialization. The use of a neck cradle prevented wound disturbance and stall confinement aided stabilization.

Abstract: Summary Effects of show jumping competition on stress levels in horses was examined. Twenty-six homes were sampled in both show and farm environments from three levels of show experience schooling, (least experience, n=11); intermediate, (moderate experience, n=6); open, (most experience, n=9). Blood samples were taken at 6 time points; 3 at the horse show and 3 at the home farm (baseline at rest, pre-schooling and post-performance over a jump course). Stress responses were assessed through comparison of the behavioral response of the horses (determined by a subjective scoring system) to plasma cortisol (F) concentrations. Physical exertion was evaluated by heart rate (HR) and plasma lactate (L) concentrations. Schooling jumpers displayed higher baseline F concentrations than open jumpers (83g±9.2 vs 46.4±10.2 ng/ml, respectively; p<.05); but not when compared to intermediate jumpers (66.2 ± 13.7 ng/ml; p>.05) at the horse show. At the farm, there were no differences in F concentrations between experience levels at a time point (p<.05). Least experienced horses displayed higher F values at rest at the show compared to the home farm. At the show, open jumpers had higher L concentrations post-exercise compared to intermediate horses (40.3±3.4 vs 25.5±4.0 mg/dL, respectively; p<.05); but were not different compared to schooling jumpers (34.8±2.0 mg/dL; p>.05). There were no differences in heart rates or behavior score between experience levels at specific time points at either the show or farm (p>.05). Low positive correlations were found between HR and F (r=.24, p<.05); HR and L (r-.48, p<.05); and HR and behavior (r=.22, p<.05). Results suggest that conditioned jumpers that have previously been exposed to horse show environments do not appear stressed during acute show-jumping competition.

Abstract: Summary Four mares and four geldings of Quarter Horse and Thoroughbred breeding were used in two simultaneous 4x4 Latin square experiments to study the effects of dietary cation-anion balance (DCAB), defined as meq ((Na+K)-C1)/kg dry matter, on urinary pH and mineral excretion in exercised horses. Diets consisted of a pelleted concentrate of corn, soybean meal and cottonseed hulls fed with bermudagrass hay. Treatments with DCAB of +5 (Low, L), +107 (Medium Low, ML), +201 (Medium High, MH) and +327 (High, H), meq ((Na+K)-Cl)/kg dry matter were formed by supplementing diet L with calcium chloride and ammonium chloride, diet ML with calcium chloride and diet H with sodium bicarbonate and potassium citrate (Table 1). Diet MH was not supplemented and served as the control treatment. Horses were conditioned aerobically for 6 weeks using long, slow, distance (LSD) workouts. During the experimental periods, horses were subjected to a combined exercise regimen alternating LSD with an interval-training protocol 6 days/week. There was a significant (P<.01) treatment effect on urine pH; least squares means for L, ML, MH and H were 6.73, 7.17, 7.38, and 7.92. Horses consuming diet L excreted more calcium in the urine (P<.05) than those consuming MH or H. Least squares means for daily urine calcium excretion tended to be linear across treatments and ranged from 19.66 g/day for diet L to 9.12 g/day for diet H. Urinary chloride excretion was higher (P<.05) for L than for MH or H. Horses fed diet H excreted more sodium (P<.05) in urine than horses fed the other diets. Lowering DCAB, increases urinary calcium loss; depending on the level of calcium intake, this could lead to negative calcium balance in exercising horses.