|
|
Hartmann, E., Christensen, J. W., & McGreevy, P. D. (2017). Dominance and Leadership: Useful Concepts in Human-Horse Interactions? Proceedings of the 2017 Equine Science Symposium, 52, 1–9.
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 suboptimal 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 horse's 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.
|
|
|
|
Burden, F., & Thiemann, A. (2015). Donkeys Are Different. Proceedings of the 2015 Equine Science Society Symposium, 35(5), 376–382.
Abstract: As a unique species of equine, the donkey has certain specific variations from the horse. This review highlights the origins of the donkey and how this impacts on its behavior, physiology, and propensity to disease. The donkey is less of a flight animal and has been used by humans for pack and draught work, in areas where their ability to survive poorer diets, and transboundary disease while masking overt signs of pain and distress has made them indispensable to human livelihoods. When living as a companion animal, however, the donkey easily accumulates adipose tissue, and this may create a metabolically compromised individual prone to diseases of excess such as laminitis and hyperlipemia. They show anatomic variations from the horse especially in the hoof, upper airway, and their conformation. Variations in physiology lead to differences in the metabolism and distribution of many drugs. With over 44 million donkeys worldwide, it is important that veterinarians have the ability to understand and treat this equid effectively.
|
|
|
|
Moeller, B. A., McCall, C. A., Silverman, S. J., & McElhenney, W. H. (). Estimation of Saliva Production in Crib-Biting and Normal Horses. Journal of Equine Veterinary Science, 28(2), 85–90.
Abstract: Increasing saliva flow to buffer the stomach has been hypothesized as a basis for crib-biting in horses. Saliva amounts in seven cribbing and seven noncribbing (control) horses were compared either pre- and post-cribbing or at pre- and post-5-minute intervals for controls. A pre-weighed cellulose sponge was used to collect saliva at the exit of the submandibular gland for 30 seconds, then reweighed. Data were analyzed as repeated measures. Mean saliva weight overall was similar between cribbing and control horses (1.2 and 1.5 g, respectively, SE = 0.2). However, mean saliva weight for pre- and post-samples (1.5 and 1.2 g, respectively, SE = 0.06) for all horses was significantly lower (P < .05) in the post-sample, indicating a drying effect of the sponge. Because of a strong tendency (P < .06) for a treatment-by-sampling time interaction, data were analyzed by sampling time and cribbing status. Mean saliva weights in the pre-sample were 0.43 g higher (P < .03) in control than cribbing horses. Control horses showed a 0.38 g decrease (P < .01) in saliva weight between pre- and post-samples, which was not evident in cribbing horses. To determine whether cribbing offset the saliva decrease seen in control horses, nine cribbing horses were sampled as before but prevented from cribbing between samples. A similar reduction (0.39 g, P < .01) in saliva weights between samples with cribbing allowed versus cribbing prevented was seen in these horses as was seen in control horses in the initial study. Because cribbing does produce saliva, gastrointestinal irritation could be a motivating cause for cribbing.
|
|
|
|
Hartmann, E., Christensen, J. W., & McGreevy, P. D. Dominance and leadership: Useful concepts in human-horse interactions? Journal of Equine Veterinary Science, .
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.
|
|
|
|
Kirkpatrick, J. F., & Turner, J. W. (1983). Seasonal ovarian function in feral mares: seasonal patterns of LH, progestins and estrogens in feral mares. J. Equine Vet. Sci., 3(4), 113–118.
Abstract: Blood was collected every 3 days for 13 months from 4 captured [female][female] of proven fertility kept adjacent to a teaser stallion. Basal plasma LH level was greater during Apr.-July (8.1+or-0.5 ng/ml) than during Nov.-Jan. (2.2+or-0.2). A total for 21 LH peaks occurred between 13 Apr. and 31 Aug. among the 4 [female][female]; many peaks exceeded 20 times the basal level, and there was a trend to a higher LH level with each succeeding peak. On all occasions except one, LH peaks were associated with progesterone levels of 0.5 ng/ml and with increases of oestrogen (peak average 43.1+or-12.1 pg/ml). Basal progesterone level during Apr.-July (1.5+or-1.2 ng/ml) did not differ significantly from that during Oct.-Jan. (1.1+or-0.7), nor did basal oestrogen level differ significantly between those 2 periods (8.4+or-3.2 and 12.9+or-4.6 pg/ml resp.). Behavioural oestrus always occurred with LH and oestrogen peaks during Apr.-July. However, behavioural oestrus was occasionally observed during Aug.-Oct., when LH peaks no longer occurred.
|
|
|
|
Kirkpatrick, J. F., & Turner, J. W. J. (1986). Comparative reproductive biology of North American feral horses. J. Equine Vet. Sci., 6, 224–230.
|
|
|
|
Gibbs, P. G., & Cohen, N. D. (2001). Early management of race-bred weanlings and yearlings on farms. J. Equine Vet. Sci., 21(6), 279–283.
Abstract: A total of 58 Thoroughbred and Quarter Horse farms
that managed 1,987 weanlings and yearlings responded to
a survey designed to better characterize early management
of racing prospects. Average age at weaning was 5.5 months
and over half of all farms kept almost three-fourths of all
weanlings to be placed in pre-race training. Variation in
feeding practices was evident and while well over half
of all farms provided balanced nutrient supply to young
horses, 20% to 40% likely fed unbalanced diets. An obvious
preference existed for semi-confinement in young horses
with plenty of free exercise. The majority of farms reported
that young prospects were fed and managed for a moderate
rate of growth. Forced exercise occurred to a much larger
extent with yearlings than weanlings and 40% of farms
described the footing as soft, but not deep. Response to the
prevalence of developmental orthopedic diseases appeared
somewhat guarded, and average injury rate was low on
farms that attributed much of injury to horses playing too
hard. Technological advancements such as photoperiod
manipulation in broodmares were widely used, while
valuable tools such as body condition scoring were utilized
to a lesser extent.
|
|
|
|
Harewood, E. J., & McGowan, C. M. (2005). Behavioral and physiological responses to stabling in naive horses. J. Equine Vet. Sci., 25(4), 164–170.
Abstract: The purpose of this study was to investigate the response of horses to confinement and isolation in a stable (indoor individual housing) for the first time using behavioral indices, heart rate, and salivary cortisol concentration. Six naive 2-year-old Australian Stock Horse fillies were examined at 4-hour intervals over 24 hours in an outdoor group paddock followed by 24 hours in indoor individual housing. Behavioral observations and scores and heart rates were recorded and saliva samples were taken at each interval. During stabling, all horses became agitated and demonstrated increased vocalization and movement. Behavioral scores were significantly higher in the indoor individual housing (P < .001). No significant difference in heart rates between the two environments was detected. Mean salivary cortisol did not increase significantly (2 ng/mL ± 1.4 ng/mL in outdoor group paddock vs 2.5 mL ± 1.2 ng/mL in indoor individual housing). No diurnal rhythm in salivary cortisol was evident in either the outdoor group paddock or indoor individual housing. The results of this study highlight that a combination of behavioral and physiological measures allow better understanding of stress, where one measurement may be misleading. First time stabling of horses elicited marked behavioral responses indicative of stress that were not reflected in increased heart rates or salivary cortisol concentrations. The lack of a diurnal cortisol rhythm and the comparatively high basal cortisol concentrations found in the outdoor group paddock environment may imply that the fillies were already stressed; therefore, stabling did not cause further aberrations detectable by salivary cortisol analysis.
|
|
|
|
Piro, M., Benjouad, A., Karom, A., Nabich, A., Benbihi, N., El Allali, K., et al. (2011). Genetic Structure of Severe Combined Immunodeficiency Carrier Horses in Morocco Inferred by Microsatellite Data. J. Equine Vet. Sci., 31(11), 618–624.
Abstract: A total of 17 microsatellite deoxyribonucleic acid loci used routinely for horse parentage control were used to evaluate genetic diversity among normal Arabian horses and severe combined immunodeficiency (SCID) carrier Arabian horses (ArS) and normal Arab-Barb horses and SCID carrier Arab-Barb horses (ArbeS). On the basis of the genotype of 186 horses, mean allelic diversity was estimated as 6.82, 5.53, and 6.7059 in normal Arabian horses, ArS, and for both groups of Arab-Barb horses, respectively. Five specific alleles were observed in ArS and ArbeS, with one common with ArS at HMS6, whereas five alleles common between ArS and ArbeS had a high frequency. Expected and observed heterozygosity showed great heterogeneity in the population studied and were similar or higher when compared with other studies on Arabian horses. Coefficient of gene differentiation Gst of Nei associated with Nei's genetic distance and multivariate correspondence analysis indicated a possible differentiation between the studied populations when analyzed separately according to breed. Probability of assignment of a horse to a specific group was assessed using a full and partial Bayesian approach. In all, 80.6% of Arab horses and 78.2% of Arab-Barb horses were assigned properly with a partial Bayesian test, which provided better results than the full one. These findings will be useful for identification of SCID carrier horses by using the microsatellite deoxyribonucleic acid loci used routinely for horse parentage control in our laboratory.
|
|
|
|
Suagee-Bedore, J. K., Linden, D. R., & Bennett-Wimbush, K. (2021). Effect of Pen Size on Stress Responses of Stall-Housed Horses Receiving One Hour of Daily Turnout. J. Equine Vet. Sci., 98, 103366.
Abstract: Group turnout provides important socializing opportunities for horses, particularly those that are primarily stalled. A high percentage of equine injuries occur during group turnout, which could partly be due to the physical constraints of fencing. To investigate appropriate paddock sizes for group turnouts, horses (n = 12) from a single herd were divided into groups of 4, stalled for 24 hours, and then turned out for 1 hour into one of three differently sized pens: 342, 263, and 184 m2 per horse. Groups rotated through pens across 3 days, receiving one treatment per day. Blood was sampled for cortisol concentrations at 08:00 hours each morning, and then at 15 and 60 minutes into the turn out sessions, and 60 minutes after return to individual stalls. Groups rotated through three turnout times: 09:00, 12:00, 14:00 hours. Counts of agonistic behaviors (chasing, contact biting, and kicking) and low-level threats (pinned ears, tail swishing, bite and kick threats) were recorded. When turned out in pens that provided 342 m2 per horse, horses exhibited reduced plasma cortisol concentrations by 15 minutes after turnout and at 1 hour after return to their stalls (P < .05). Horses in pens providing 184 m2 per horse exhibited greater agonistic (P < .001) and low-level threat (P < .01) behaviors than horses in larger pens. These data provide insight into appropriate pen sizes for horses from established herds. Providing at least 342 m2 per horse may reduce the chance of injury in horses accustomed to group turnout.
|
|
