Sabrina Briefer Freymond

Slow-feeders, a type of hay dispenser, are becoming increasingly popular among horse keepers, yet there is limited knowledge about their effects on horses’ oral and musculoskeletal health. Existing studies on this topic use varied protocols, complicating comparisons and replication. Thus, validated protocols are essential, ensuring consistent intra- and inter-rater agreement and reliability over time, while also being feasible for implementation in research. In this work, we designed a protocol for the assessment of musculoskeletal health (MSH) and adapted an existing protocol for the assessment of rostral oral cavity (incisors and gums; ROC). We evaluated the agreement between raters obtained with the two protocols, tested their intra- and inter-rater reliability using Kappa and Gwet indices, investigated their feasibility of implementation, and discussed their validity in the context of previous findings. The MSH protocol demonstrates promising inter-observer reliability and substantial intra-rater reliability, indicating consistent use by various practitioners over time. While improvements could enhance its accuracy, the protocol is accessible to those with limited experience, quick to implement, and applicable to all horse types. Preliminary results suggest that this protocol may be a valid tool for assessing MSH in horses. The ROC protocol, with the exception of one item, showed substantial to almost perfect inter- and intra-rater reliability. It has been successfully employed in two studies, yielding consistent findings on the prevalence and severity of dental abnormalities. This protocol demonstrates potential as a non-invasive method for assessing the condition of the rostral oral cavity in horses. Rater training was identified as crucial for the reliability of both protocols. Notably, the Kappa and Gwet indices produced considerably different results, suggesting careful consideration is needed when using the Kappa index to assess protocol reliability. Further research should focus on refining these protocols and exploring their broader applications to enhance their accuracy and ease of use. This study contributes significantly to the field by providing reliable, non-invasive methods for assessing key aspects of equine health, ultimately aiming to improve horse welfare. The findings emphasize the need for standardized protocols to facilitate consistent and accurate evaluations, benefiting both scientific research and practical care in the equine industry.

Slowfeeders (SFs) are feed dispensers designed to mechanically slow feed intake. As such, they are a promising tool for improving the welfare of horses by meeting their behavioural and physiological feeding needs while controlling the risk of obesity. However, there is limited knowledge regarding the current use of SFs by horse owners and the profile of horses using such feeders. The objective of this questionnaire-based study was to evaluate the slow-feeding practices among horse owners and yard operators in some French-speaking European countries (Belgium, France and Switzerland). We received 1,283 replies, revealing that the population of horses fed with SFs differs from the general population of ridden horses in several aspects, such as age, training, and housing. This information is valuable for ensuring representative sampling in future studies. Regarding the type of SF used, more than 85% of the respondents reported using hay nets, with hay nets covering the hay in the hayrack or surrounding a bale of hay being particularly popular. The main reasons for using SFs were waste management, weight reduction, and increased feeding time for horses. Most respondents did not encounter any issues when using SFs and less than 10% of respondents reported health problems and accidents resulting from the use of SF. Differences were also found between countries and between operators and owners, indicating that different user profiles have varying requirements for the feeder they use.

The personality of a horse is thought to influence the quality of horse-human relationship. In this study, we developed a questionnaire to assess horse’s personality. For validation, 2431 horse-owners filled it out for their horse along with an existing questionnaire to determine their personality. Out of this sample, 39 horses were tested in personality tests, to monitor the owners' responses to the questionnaires. We then compared the results of the equine questionnaire to the results of the personality tests and then investigated which components of the equine personality and of the owner, were similar. Personality scores obtained from the questionnaire showed, first, that owners with a higher Emotional stability score perceived their horses to be also easily stressed (r = 0.26, N = 2431, p < 0.05) and secondly that Conscientious owners described their horses as Conscientious as well (r = 0.26, N = 2431, p < 0.05). The personality tests confirmed the scores for the Emotional stability trait, i.e. easily stressed horses were more active during personality tests (r = 0.56, N = 39, p < 0.05). These results do not allow us to exclude the effect of the owner's personality on his horse in the long term.

In order to improve the housing conditions of stallions in individual boxes, we tested a so-called “social box” allowing increased physical contact between neighbouring horses. This study investigated whether housing stallions in social boxes changes the number of social interactions during carriage driving. We hypothesised that the stay in social boxes would decrease the number of unwanted social interactions between stallions when driven in pairs. Eight Franches-Montagnes breeding stallions were observed when driven in pairs with a “neutral” stallion housed in a so-called “conventional box”, strongly limiting physical contact. They were driven on a standardised route over the course of four days before, during, and after being housed in social boxes. The type and frequency of behaviours of the pairs and the interventions of the groom and the driver during the test drives were assessed live and using video recordings. Results from linear mixed-effect models show that unwanted social interactions decreased during and after the stallions were housed in the social box (p < 0.001). Stallions’ interactions also decreased over the four days (p < 0.01), suggesting a habituation to the test conditions by learning not to interact, or by subtly settling dominance. The social box tended to decrease unwanted social behaviours of stallions driven in pairs and could therefore be used as an environmental enrichment for horses.

Although stereotypic behaviors are a common problem in captive animals, why certain individuals are more prone to develop them remains elusive. In horses, individuals show considerable differences in how they perceive and react to external events, suggesting that this may partially account for the emergence of stereotypies in this species. In this study, we focused on crib-biting, the most common stereotypy displayed by horses. We compared how established crib-biters (“CB” = 19) and normal controls (“C” = 18) differed in response to a standard “personality” assessment test battery, i.e., reactivity to humans, tactile sensitivity, social reactivity, locomotor activity, and curiosity vs. fearfulness (both in novel and suddenness situations). Our analyses showed that crib-biters only differed from control horses in their tactile sensitivity, suggesting an elevated sensitivity to tactile stimuli. We suggest that this higher tactile sensitivity could be due to altered dopamine or endogenous opioid physiology, resulting from chronic stress exposition. We discuss these findings in relation to the hypothesis that there may be a genetic predisposition for stereotypic behavior in horses, and in relation to current animal husbandry and management practices.

Stereotypies in animals are thought to arise from an interaction between genetic predisposition and sub-optimal housing conditions. In domestic horses, a well-studied stereotypy is crib-biting, an abnormal behaviour that appears to help individuals to cope with stressful situations. One prominent hypothesis states that animals affected by stereotypies are cognitively less flexible compared to healthy controls, due to sensitization of a specific brain area, the basal ganglia. The aim of this study was to test this hypothesis in crib-biting and healthy controls, using a cognitive task, reversal learning, which has been used as a diagnostic for basal ganglia dysfunction. The procedure consisted of exposing subjects to four learning tasks; first and second acquisition, and their reversals. For each task, we measured the number of trials to reach criterion and heart rate and heart-rate variability. Importantly, we did not try to prevent crib-biters from executing their stereotypic behaviour. We found that the first reversal learning task required the largest number of trials, confirming its challenging nature. Interestingly, the second reversal learning task required significantly fewer trials to reach criterion, suggesting generalisation learning. However, we did not find any performance differences across groups; both stereotypic and control animals required a similar numbers of trials and did not differ in their physiological responses. Our results thus challenge the widely held belief that crib-biting horses, and stereotypic animals more generally, are cognitively impaired. We conclude that cognitive underperformance may occur in stereotypic horses if they are prevented from crib-biting to cope with experienced stress.

Non-human animals often produce different types of vocalisations in negative and positive contexts (i.e. different valence), similar to humans, in which crying is associated with negative emotions and laughter is associated with positive ones. However, some types of vocalisations (e.g. contact calls, human speech) can be produced in both negative and positive contexts, and changes in valence are only accompanied by slight structural differences. Although such acoustically graded signals associated with opposite valence have been highlighted in some species, it is not known if conspecifics discriminate them, and if contagion of emotional valence occurs as a result. We tested whether domestic horses perceive, and are affected by, the emotional valence of whinnies produced by both familiar and unfamiliar conspecifics. We measured physiological and behavioural reactions to whinnies recorded during emotionally negative (social separation) and positive (social reunion) situations. We show that horses perceive acoustic cues to both valence and familiarity present in whinnies. They reacted differently (respiration rate, head movements, height of the head and latency to respond) to separation and reunion whinnies when produced by familiar, but not unfamiliar individuals. They were also more emotionally aroused (shorter inter-pulse intervals and higher locomotion) when hearing unfamiliar compared to familiar whinnies. In addition, the acoustic parameters of separation and reunion whinnies affected the physiology and behaviour of conspecifics in a continuous way. However, we did not find clear evidence for contagion of emotional valence. Horses are thus able to perceive changes linked to emotional valence within a given vocalisation type, similar to perception of affective prosody in humans. Whinnies produced in either separation or reunion situations seem to constitute acoustically graded variants with distinct functions, enabling horses to increase their apparent vocal repertoire size.