Abstract: This study addresses development and validation of a composite multifactorial pain scale (CPS) in an experimental equine model of acute orthopaedic pain. Eighteen horses were allocated to control (sedation with/without epidural analgesia – mixture of morphine, ropivacaine, detomidine and ketamine) and experimental groups: amphotericin-B injection in the tarsocrural joint induced pain and analgesia was either i.v. phenylbutazone administered post-induction of synovitis, or pre-emptive epidural mixture, or a pre-emptive combination of the 2. Inter- and intra-observer reproducibility was good (0.8<K<1). The key specific and sensitive behavioural indices were response to palpation of the painful area, posture, and, of lesser value, pawing on the floor, kicking at abdomen and head movement. Of particular interest was the statistical correlation observed between the CPS and both non-invasive blood pressure (P<0.0001) and blood cortisol (P<0.002). This study established the value of some behavioural and physiological criteria in determining equine orthopaedic pain intensity and clearly demonstrated that pre-emptive, multimodal analgesia provided better management than the two other protocols tested.

Abstract: There is evidence that more than 47% of the sports horse population in normal work may be lame, but the lameness is not recognized by owners or trainers. An alternative means of detecting pain may be recognition of behavioral changes in ridden horses. It has been demonstrated that there are differences in facial expressions in nonlame and lame horses. The purpose of this study was to develop a whole horse ethogram for ridden horses and to determine whether it could be applied repeatedly by 1 observer (repeatability study, 9 horses) and if, by application of a related pain behavior score, lame horses (n = 24) and nonlame horses (n = 13) could be differentiated. It was hypothesized that there would be some overlap in pain behavior scores among nonlame and lame horses; and that overall, nonlame horses would have a lower pain behavior score than lame horses. The ethogram was developed with 117 behavioral markers, and the horses were graded twice in random order by a trained specialist using video footage. Overall, there was a good correlation between the 2 assessments (P < 0.001; R2 = 0.91). Behavioral markers that were not consistent across the 2 assessments were omitted, reducing the ethogram to 70 markers. The modified ethogram was applied to video recordings of the nonlame horses and lame horses (ethogram evaluation). There was a strong correlation between 20 behavioral markers and the presence of lameness. The ethogram was subsequently simplified to 24 behavioral markers, by the amalgamation of similar behaviors which scored similarly and by omission of markers which showed unreliable results in relation to lameness. Following this, the maximum individual occurrence score for lame horses was 14 (out of 24 possible markers), with a median and mean score of 9 (±2 standard deviation) compared with a maximum score of 6 for nonlame horses, with a median and mean score of 2 (±1.4). For lame horses, the following behaviors occurred significantly more (P < 0.05, chi-square): ears back, mouth opening, tongue out, change in eye posture and expression, going above the bit, head tossing, tilting the head, unwillingness to go, crookedness, hurrying, changing gait spontaneously, poor quality canter, resisting, and stumbling and toe dragging. Recognition of these features as potential indicators of musculoskeletal pain may enable earlier recognition of lameness and avoidance of punishment-based training. Further research is necessary to verify this new ethogram for assessment of pain in ridden horses.

Abstract: This field study tested the hypothesis that domestic horses living under putatively challenging-to-welfare conditions (for example involving social, spatial, feeding constraints) would present signs of poor welfare and co-occurring pessimistic judgement biases. Our subjects were 34 horses who had been housed for over 3 years in either restricted riding school situations (e.g. kept in single boxes, with limited roughage, ridden by inexperienced riders; N = 25) or under more naturalistic conditions (e.g. access to free-range, kept in stable social groups, leisure riding; N = 9). The horses' welfare was assessed by recording health-related, behavioural and postural indicators. Additionally, after learning a location task to discriminate a bucket containing either edible food ('positive' location) or unpalatable food ('negative' location), the horses were presented with a bucket located near the positive position, near the negative position and halfway between the positive and negative positions to assess their judgement biases. The riding school horses displayed the highest levels of behavioural and health-related problems and a pessimistic judgment bias, whereas the horses living under more naturalistic conditions displayed indications of good welfare and an optimistic bias. Moreover, pessimistic bias data strongly correlated with poor welfare data. This suggests that a lowered mood impacts a non-human species' perception of its environment and highlights cognitive biases as an appropriate tool to assess the impact of chronic living conditions on horse welfare.

Abstract: Summary Ten trotting Standardbred colts were recorded by high-speed cinematography at the ages of eight, 12 and 18 months. The horses were trotting on a treadmill operating at 4.0 m/secs. Five horses were subjected to a programme of intensified training from eight months of age, whereas the others were not trained and acted as controls. The films were analysed on a semi-automatic film-reading equipment and a number of variables used to demonstrate the gait symmetry were calculated and scaled by computer. Certain differences between left and right diagonal and contralateral pair of limbs, respectively, were noted, suggesting that laterality in horses may be inherited. The most pronounced systematic differences were found in 18-month old horses in the trained group. The results show the importance of careful gait examination and comprehensive coordination training at an early age.

Abstract: ABSTRACT For many ecosystems, feral horses are increasingly becoming an important if not dominant component of ungulate biomass and hence influence on community dynamics. Yet we still know little of how horses contribute to key ecological interactions including predator-prey and indirect competitive relationships at a community level. Notably, feral species like horses can exhibit life-history traits that differ from that of native (mainly artiodactyl) herbivore competitors. Artificial selection for traits like increased, early, or extended reproduction that have yet to be reversed by natural selection, coupled with naturally selected differences in anatomy and behavior, in addition to unique management objectives for horses compared to other species, means that the dynamics of feral horse populations are not likely to align with what might be expected of other large herbivores. Unexpected population dynamics and inherent biological asymmetries between native ungulates and feral horses may therefore influence the former via direct competition for shared resources and through enemy-mediated interactions like apparent competition. In several localities feral horses now co-exist with multiple native prey species, some of which are in decline or are species at risk. Compounding risks to native species from direct or indirect competitive exclusion by horses is the unique nature and socio-political context of feral horse management, which tends towards allowing horse populations to be limited largely by natural, density-dependent factors. We summarize the inherent asymmetries between feral horse biology and that of other ungulate prey species with consequences for conservation, focusing on predator-prey and emerging indirect interactions in multi-prey systems, and highlight future directions to address key knowledge gaps in our understanding of how feral horses may now be contributing to the (re)structuring of food webs. Observations of patterns of rapid growth and decline, and associated skews in sex ratios of feral horse populations, indicate a heightened potential for indirect interactions among large ungulate prey species, where there is a prevalence of feral horses as preferred prey, particularly where native prey are declining. In places like western North America, we expect predator-prey interactions involving feral horses to become an increasingly important factor in the conservation of wildlife. This applies not only to economically or culturally important game species but also at-risk species, both predators (e.g., wolves [Canis lupus], grizzly bears [Ursus arctos]) and prey (e.g., woodland caribou [Rangifer tarandus caribou]), necessitating an ecological understanding of the role of horses in natural environments that goes beyond that of population control. ? 2021 The Wildlife Society.