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Enileeva, N. K. (1987). [Ecological characteristics of horse stomach botflies in Uzbekistan]. Parazitologiia, 21(4), 577–579.
Abstract: The paper describes the flight periods and dynamics of abundance of horse botflies, life span of females and males, effect of environmental factors on the activity of flies and their behaviour, potential fecundity of different species of botflies, duration of embryonal development, preservation of viability of larvae in egg membranes, localization of different stages of botflies in the host, and methods of their control.
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Erber, R., Wulf, M., Aurich, J., Becker-Birck, M., Rose-Meierhöfer, S., Möstl, E., et al. (2012). Physiological stress parameters in sport horse mares transferred from group housing to individual stabling. In K. Krueger (Ed.), Proceedings of the 2. International Equine Science Meeting (Vol. in press). Wald: Xenophon Publishing.
Abstract: Initial equestrian training and especially first mounting of a rider are stressful challenges for young horses (1). Most young horses are raised in groups but, in association with equestrian training, they are commonly transferred to individual stabling in loose boxes. Although, in most stables, visual contact with horses in adjacent boxes is possible, separation from the herd might be an additional stressor. We have studied physiological stress parameters, in 3-year-old sport horse mares (n=8), transferred from a group stable with access to a paddock to individual boxes without paddock. Once stabled in the individual boxes, mares underwent a standard training for young horses. Horses had been accustomed to lunging and tolerating a rider on their back several weeks before the study. Mares were studied from 5 days before to 5 days after changing the stable. Cortisol concentration in saliva, locomotion activity (ALT pedometers), heart rate (HR) and HR variability (RMSSD: root mean square of successive beat-to-beat intervals) were determined. We hypothesized that the change of the stable increases cortisol release and is associated with changes in HR and RMSSD and reduced locomotion. Before mares were moved to individual boxes, cortisol concentration showed a pronounced diurnal rhythm with values around 0.6 ng/ ml in the morning and a continuous decrease throughout the day. When the mares were moved to individual boxes, cortisol concentration increased to 1.8±0.2 ng/ml and did not return to baseline values within 6 h (p<0.05 over time). On subsequent days, a diurnal rhythm was re-established but shifted to a higher level than before. Locomotion activity determined by ALT pedometers was increased for some minutes only after mares has been placed in individual boxes but was only slightly higher than during the time mares spent with the group in a paddock. On days 2-5 in individual boxes, locomotion activity was reduced compared to the group stable. HR increased and the HRV variable RMSSD decreased when mares were separated. In conclusion, separating horses during initial training from their group is an additional stressor, although the stress is less pronounced than induced by other social challenges, e.g. weaning of foals (2). When stabled in individual boxes, mares move less than when kept as a group. Horses kept in a group thus appear to exercise themselves freely, such an effect is absent when the animals are kept individually.
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Ermilina, J. A. (2012). Dominance hierarchy in feral horses in Rostov Region. In K. Krueger, & (Ed.), Proceedings of the 2. International Equine Science Meeting (Vol. in press). Wald: Xenophon Publishing.
Abstract: Horses maintain the social structure through the establishment of dominant-subordinate hierarchical relationships, both within and between groups. The object of study was the feral horse population, living on the Vodnyi Isl, Manych-Ghudilo Lake, on the territory of Rostov Region, S Russia the State Nature Biosphere Reserve “Rostov”. The social structure of this population is represented by the harem and bachelor groups, and their variety – the “mixed”groups, the presence and composition of which is atypical for the populations of feral horses. The main objectives of this work were to identify the hierarchical structure of different types of social groups and the role of the stallions in them, defining the dominance rank of animals. The method of continuous logging occurred aggressive reaction, ritualized interaction between stallions, take into account the direction of interactions between individuals. We observed 5 harem, 3 bachelor and 3 mixed groups. Each group was studied for a total of 60 h (8 h per group per days).Behavioral observations were carried out in summer 2009-2011. Based on the number and direction of aggressive interactions the hierarchical coefficient was calculated for individual horses (Ivanov et al, 2007). Harem group consists of an adult stallion (<5 years old) and a few mares with their offspring. Our observations of harem groups confirm the previously known information about this type of social groups (Berger, 1986; Carson, Wood-Gush, 1983, Keiper, 1983). Hierarchical system between mares is close to linear with reversal. The stallion is not included in the hierarchy of the mares; he is the leader and serves to maintain the integrity of the group and inter-group hierarchy, and has reproductive function. Bachelor groups consist of stallions 2-3 years and older who do not have their own harem. It is known that dominance hierarchy in these groups is linear, young males or males who recently had joined the group have low ranks (Berger, 1977; Houpt, Keiper, 1982; Kirillov Paklina, 1990). In observed bachelor groups dominant stallion have a significantly higher rank in the hierarchy. However, among other stallions is not always observed strict linear hierarchy – some individuals have very similar ranks. Function of managing the group and maintaining the intergroup hierarchy can be distributed among the all stallions in the group. Mixed groups are composed of several mature stallions, one or more mares (sometimes with the offspring). In the study population in this type of social groups animals may be mature (age 5 and older) and semi-mature (2-5 years). The hierarchy of these atypical groups has not been studied. In the studied 3 mixed groups stallions have very similar hierarchical rank, dominant and subordinate stallions share a function of managing the group, participation in ritualized interactions. Our studies have revealed the plasticity of the hierarchical structure of groups of horses and the need to further investigate the distribution of social roles among stallions.
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Faber, M. J., van Weeren, P. R., Schepers, M., & Barneveld, A. (2003). Long-term follow-up of manipulative treatment in a horse with back problems. J Vet Med A Physiol Pathol Clin Med, 50(5), 241–245.
Abstract: In order to objectively quantify the effect of manipulation on back-related locomotion anomalies in the horse, a recently developed kinematic measuring technique for the objective quantification of thoracolumbar motion in the horse was applied in a dressage horse that was suffering from a back problem. In this horse, clinically, a right-convex bending (scoliosis) from the 10th thoracic vertebra to the second lumbar vertebra was diagnosed. As a result, there was a marked asymmetric movement of the thoracolumbar spine. Functionally, there was severe loss of performance. Thoracolumbar motion was measured in terms of ventrodorsal flexion, lateral flexion, and axial rotation using an automated gait analysis system. Measurements were repeated before and 2 days after treatment, before the second treatment 3 weeks later, and at 4 weeks and 8 months after the second treatment to assess long-term effect. At the same time, performance of the horse was assessed subjectively by the trainer as well. Symmetry of movement improved dramatically after the first treatment. After this, there was a slight decrease in symmetry, but 8 months after the last treatment the symmetry indexes for the various joints were still considerably better than during the first (pre-treatment) measuring session. Subjectively, the trainer did not notice improvement until after measurement session 4. Between sessions 4 and 5 (at 4 weeks and 8 months after the second treatment) there was a change of trainer. The new trainer did not report any back problem, and succeeded in bringing the horse back to its former level in competition. It is concluded that manipulation had a measurable influence on the kinematics of the thoracolumbar spine. However, it is recognized that an improvement in symmetry of motion is not equivalent to clinical improvement and that other measures, such as changes in management, may be more decisive.
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Falewee, C., Gaultier, E., Lafont, C., Bougrat, L., & Pageat, P. (2006). Effect of a synthetic equine maternal pheromone during a controlled fear-eliciting situation. Appl. Anim. Behav. Sci., 101(1-2), 144–153.
Abstract: Horses are known to show fear reactions when confronted with novelty and this can be a considerable hindrance in the context of working situations such as riding, dressage or racing. The aim of the present study was to measure the potential effects of a synthetic analogue of the Equine Appeasing Pheromone on saddled horses when subjected to a stressful situation using a double-blinded, placebo controlled study design. A group of 40 horses was analyzed during this study and horses were divided by sex, breed and reactivity into two homogenized groups. The test, which consisted of walking the horse through a fringed curtain, was selected from a range of tests which are used to assess behaviour for the selection of French breeding stock. Horses that could have been subjected to the test on a previous occasion, and therefore be familiar with it, were not included. Behavioural and physiological parameters were both taken into account with measures of time to go through the curtain, fear related typical behavioural patterns, based on available literature detailed in the bibliography, and heart rate being recorded. Parameters were analyzed by means of Mann-Whitney U-test. Significant differences were noticed between the two groups concerning heart rate data during the test (UMeanHR = 100.5, pMeanHR = 0.02; UMaxHR = 75, pMaxHR = 0.001) and during the whole measured period (UMeanHR = 67, pMeanHR = 0.005; UMaxHR = 58, pMaxHR = 0.002). Observation of the animals also revealed less behavioural items characteristic of fear within the treated group. As a result, horses performed the test with a better time performance when they received the pheromone analogue (U = 62, p = 0.002). The main parameter, area under the HR graph, is based on heart rate measure and performance. Differences noticed (U = 74, p = 0.002) for this parameter lead to the conclusion that horses who received EAP underwent less stress related consequences in terms of their cardiac physiology. As horses are subjected to a number of foreseeable stressful events this study suggests that the use of Equine Appeasing Pheromone could be a significant factor in improving the welfare of this species.
Keywords: Horses; Behaviour; Fear; Pheromone; Heart rate; Performance
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Farmer, K., Krueger, K., & Byrne, R. (2010). Visual laterality in the domestic horse (Equus caballus) interacting with humans. Anim. Cogn., 13, 229–238.
Abstract: Most horses have a side on which they are easier to handle and a direction they favour when working on a circle, and recent studies have suggested a correlation between emotion and visual laterality when horses observe inanimate objects. As such lateralisation could provide important clues regarding the horse’s cognitive processes, we investigated whether horses also show laterality in association with people. We gave horses the choice of entering a chute to left or right, with and without the passive, non-interactive presence of a person unknown to them. The left eye was preferred for scanning under both conditions, but significantly more so when a person was present. Traditionally, riders handle horses only from the left, so we repeated the experiment with horses specifically trained on both sides. Again, there was a consistent preference for left eye scanning in the presence of a person, whether known to the horses or not. We also examined horses interacting with a person, using both traditionally and bilaterally trained horses. Both groups showed left eye preference for viewing the person, regardless of training and test procedure. For those horses tested under both passive and interactive conditions, the left eye was preferred significantly more during interaction. We suggest that most horses prefer to use their left eye for assessment and evaluation, and that there is an emotional aspect to the choice which may be positive or negative, depending on the circumstances. We believe these results have important practical implications and that emotional laterality should be taken into account in training methods.
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Fazio, E., Medica, P., Cravana, C., Giacoppo, E., & Ferlazzo, A. (2008). Effect of Short-Distance Road Transport on Thyroid Function, Rectal Temperature, Body Weight and Heart Rate of Stallions. In IESM 2008.
Abstract: Aim of study was to investigate the effects of transport stress on thyroid response, body weight, rectal temperature and heart rate changes in one hundred twenty-six healthy stallions in basal conditions, before and after short road transport. One hundred twenty-six Thoroughbreds and crossbreds stallions with previous travelling experience, aged 4 to 15 yr, were transported by road in a commercial trailer for a period of 3 h (distance <300 km). Blood samples and physiological parameters were collected at 0800 (basal I) and at 1100 (basal II), in each horse“s box, one week before the loading and transport in basal conditions, and one week later, at 0800 immediately before loading (pre-transport), and after 3 h period of transport and unloading, on their arrival at the breeding stations (post-transport), in each new horse”s box, within 30 min. Increases in circulating T3, T4 and fT4 levels (P < 0.01), but not for fT3 levels, were observed after transport, as compared to before loading values, irrespective of different breed. Lower T4 and fT4 levels were observed in basal II (P < 0.01) than basal I and before loading values (pre-transport). After transport Thoroughbreds showed higher fT3 (P < 0.05) and fT4 (P < 0.01) levels than crossbred stallions. No significant differences for T3 and T4 changes were observed. A significant increase in rectal temperature (P < 0.01) and heart rate (P < 0.05) was observed after transport, as compared to before loading values (pre-transport). No differences between basal I, basal II and before loading values (pre-transport) for physiological parameters were observed.
The highest T3, T4 and fT4 levels recorded after short transport seem to suggest a preferential release from the thyroid gland. The results indicate that short road transport stress contributes significantly to thyroid hormone changes, according to different breed, and to the increase in rectal temperature and heart rate. No differences related to different age were observed. |
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Feh, C., & Munkhtuya, B. (2008). Male infanticide and paternity analyses in a socially natural herd of Przewalski`s horses: Sexual selection? Behav. Process., 78(3), 335–339.
Abstract: The sexual selection hypothesis explains infanticide by males in many mammals. In our 11-year study, we investigated this hypothesis in a herd of Przewalski's horses where we had witnessed infanticidal attacks. Infanticide was highly conditional and not simply linked to takeovers. Attacks occurred in only five of 39 cases following a takeover, and DNA paternity revealed that, although infanticidal stallions were not the genetic fathers in four cases out of five, stallions present at birth did not significantly attempt to kill unrelated foals. Infanticide did not reduce birth intervals; only in one case out of five was the infanticidal stallion, the father of the next foal; mothers whose foals were attacked subsequently avoided associating with infanticidal stallions. Therefore, evidence for the sexual selection hypothesis was weak. The “human disturbance” hypothesis received some support, as only zoo bred stallions which grew up in unnatural social groups attacked foals of mares which were pregnant during takeovers.
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Feist, J. D., & McCullough, D. R. (1975). Reproduction in feral horses. J Reprod Fertil Suppl, (23), 13–18.
Abstract: A behavioural study of feral horses was conducted on the Pryor Mountain Wild Horse Range in the western United States. All 270 horses on the Range were identified individually. The sex ratio was nearly balanced. Foal to adult female ratio was 43-2:100. Morality was concentrated among foals and old horses. Horses were organized as forty-four harem groups each with a dominant stallion, one to two immature stallions, one to three immature mares, one to three adult mares and their yearling and foal offspring, and 23 bachelor groups of one to eight stallions. Harem groups were quite stable year-round because of dominance and leadership by the stallions and group fidelity by mares and their offsring. Most changes occurred during the breeding season and involved immature females. Defeat of dominant stallions was infrequent. Immature males were tolerated because of their submissive behaviour. Bachelor stallion groups were inherently unstable. Mares came into heat after foaling in May/June, and were mated by harem stallions only.
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Feist, J. D., & McCullough, D. R. (1976). Behavior patterns and communication in feral horses. Z. Tierpsychol., 41(4), 337–371.
Abstract: The social behavior of feral horses was studied in the western United States. Stable harem groups with a dominant stallion and bachelor hermaphrodite hermaphrodite groups occupied overlapping home ranges. Groups spacing, but not territoriality, was expressed. Harem group, stability resulted from strong dominance by dominant stallions, and fidelity of group members. Eliminations of group members were usually marked by urine of the dominant stallion. Hermaphrodite-hermaphrodite aggression involved spacing between harems and dominance in bachelor groups. Marking with feces was important in hermaphrodite-hermaphrodite interactions. Foaling occurred in May and early June, following the post-partum estrous. All breeding was done by harem stallions. Young were commonly nursed through yearling age. These horses showed social organizations similar to other feral horses and plains zebras.
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