Janne Winther Christensen

Effects of individual versus group stabling on social behaviour in domestic stallions

Domestic horses (Equus caballus) are typically kept in individual housing systems, in which they are deprived of physical contact. In order to study the effects of social restrictions on behaviour in young horses, nineteen 2-year-old stallions were housed either singly (n=7), or in groups of three (n=12) for 9 months. Subsequently, the stallions were released into two separate 2 ha enclosures according to treatment, and recordings were made on social interactions and nearest neighbours during a 6-week-period, 28 h per week. Previously group stabled stallions frequently had a former group mate as their nearest neighbour (P=0.001), whereas previously singly stabled stallions did not associate more with their former box neighbours, to whom physical contact was limited by bars during the previous treatment. The nearest neighbour was more frequently recorded to be within one horselength of singly stabled than of group stabled stallions (P=0.005). More aggressive behaviour was recorded in the group of previously singly stabled stallions, i.e. bite threats (P=0.032), whereas group stabled stallions tended to make more use of subtle agonistic interactions (displacements, submissive behaviour). Singly stabled stallions also responded to the 9 months of social deprivation by significantly increasing the level of social grooming (P<0.001) and play behaviour (P<0.001), when subsequently interacting freely with other horses. The increased occurrence may relate to a build-up of motivation (a rebound effect), as well as to external factors, such as playful pasture companions and the increased space allowance of the pasture. It is concluded that 2-year-old domestic stallions are sensitive to social deprivation and that stabling has long-term effects, lasting 6 weeks at least, on the social behaviour in stallions.

Effects of a calm companion on fear reactions in naive test horses

REASON FOR PERFORMING STUDY In fear-eliciting situations, horses tend to show flight reactions that can be dangerous for both horse and man. Finding appropriate methods for reducing fearfulness in horses has important practical implications. OBJECTIVES To investigate whether the presence of a calm companion horse influences fear reactions in naive subject horses. HYPOTHESES The presence of a habituated (calm) companion horse in a fear-eliciting situation can reduce fear reactions in naive subject horses, compared to subject horses with a nonhabituated companion (control). METHODS Minimally handled (n = 36), 2-year-old stallions were used, 18 as subjects and 18 as companions. Companion horses (n = 9) were habituated to an otherwise frightening, standardised test stimulus (calm companions), whereas the rest (n = 9) of the companion horses remained nonhabituated (control companions). During the test, unique pairs of companion and subject horses were exposed to the test stimulus while heart rate and behavioural responses were registered. Subsequently, subject horses were exposed to the stimulus on their own (post test). RESULTS Subject horses, paired with a calm companion horse, showed less fear-related behaviour and lower heart rate responses compared to subject horses with control companions. Results from the post test suggest that the difference between treatment groups remained in the subsequent absence of companion horses. CONCLUSIONS AND POTENTIAL RELEVANCE It appears possible to reduce fear reactions in young, naive horses by allowing them to interact with a calm companion horse in fear-eliciting situations.

Rein tension acceptance in young horses in a voluntary test situation

REASONS FOR PERFORMING THE STUDY During riding, horses are frequently exposed to pressure from the rider, e.g. through the bit and reins, but few studies have investigated at which point rein tension becomes uncomfortable for the horse. OBJECTIVES To investigate how much rein tension young inexperienced horses are willing to accept in order to obtain a food reward; whether the tension acceptance changes during 3 consecutive test days; and whether rein tension correlates with the expression of conflict behaviour and heart rate. HYPOTHESES Pressure-naïve horses will apply only little rein tension in the first voluntary trial, but their acceptance will gradually increase. High levels of rein tension will lead to expression of conflict behaviour and increases in heart rate. METHODS Fifteen 2-year-old, bridle-naïve mares were encouraged to stretch their head forward (across a 0.95 m high metal bar) to obtain a food reward in a voluntary test situation. On each test day, each horse was exposed to 2 control sessions (loose reins), an intermediate and a short rein session (1 min/session). Rein tension, heart rate and behaviour were recorded. RESULTS The horses applied significantly more tension on the first day (mean rein tension: 10.2 N), compared to the second and third test day (Day 2: 6.0 and Day 3: 5.7 N). The horses showed significantly more conflict behaviour in the short rein treatment. There was no treatment effect on heart rate. CONCLUSIONS AND POTENTIAL RELEVANCE The horses applied the highest rein tension on the first day, and apparently learned to avoid the tension, rather than habituate to it. Rein tension correlated with expression of conflict behaviour, indicating that the horses found the tension aversive. Further studies should focus on the correlation between rein tension and conflict behaviour in ridden horses.

Therapeutic effects of dog visits in nursing homes for the elderly

Previous studies have suggested that visiting dogs can have positive effects on elderly people in nursing homes. We wanted to study the effects of biweekly dog visits on sleep patterns and the psychiatric well‐being of elderly people.

Object habituation in horses: The effect of voluntary versus negatively reinforced approach to frightening stimuli

REASONS FOR PERFORMING THE STUDY The ability of horses to habituate to novel objects influences safety in the horse-human relationship. However, the effectiveness of different habituation techniques has not been investigated in detail. OBJECTIVES 1) To investigate whether horses show increased stress responses when negatively reinforced to approach novel objects, compared with horses allowed to voluntarily explore the objects and 2) whether a negatively reinforced approach facilitates object habituation. METHODS Twenty-two 2-3-year-old Danish Warmblood geldings were included. Half of the horses (NR group) were negatively reinforced by a familiar human handler to approach a collection of novel objects in a test arena. The other half were individually released in the arena and were free to explore the objects (VOL group). On the next day, the horses were exposed to the objects again without a human handler, to investigate the rate of habituation. Behavioural and heart rate responses were recorded. RESULTS All VOL horses initially avoided the unknown objects, whereas the handler was able to get all NR horses to approach and stand next to the objects within the first 2 min session. The NR horses had a significantly longer duration of alertness and a higher max heart rate in the first session. On the next day, however, NR horses spent significantly less time investigating the objects and had a shorter latency to approach a feed container, placed next to the objects, indicating increased habituation. CONCLUSION A negatively reinforced approach to novel objects increases stress responses during the initial exposure but facilitates habituation in young horses. POTENTIAL RELEVANCE Although a negatively reinforced approach appears beneficial for habituation, the procedure should be carefully managed due to increased stress responses in the horse, which may constitute a safety risk. Further experiments should aim to investigate differences in stimulus intensity.

Behavioral Responses of Nursing Home Residents to Visits From a Person with a Dog,a Robot Seal or aToy Cat

ABSTRACT Previous studies suggest that contact with dogs can positively affect the wellbeing of elderly people in nursing homes, but there is a lack of research investigating the causal pathways of these effects. One such path- way may relate to the behavioral responses of the elderly when interacting with a dog. The present study compared the immediate behavioral responses of nursing home residents to bi-weekly visits from a person accompanied by either a dog, a robot seal (PARO®), or a soft toy cat, using a randomized controlled design. A total of 100 nursing home residents com- pleted the study. Each participant received a total of 12 visits, during which their behaviors, including interactions between the visitor and the accom- panying animal (real or artificial), were recorded. Also, data on cognitive im- pairment, presence of depressive symptoms, age, time lived in the nursing home, dementia diagnoses, and gender were collected. We found that the immediate responses to, and interaction with, the visiting animal depended on the type of animal that was brought along. The dog and the interactive robot seal triggered the most interaction, in the form of physical contact (F(2,103) = 7.50, p < 0.001), eye contact (F(4,151) = 6.26, p < 0.001), and verbal communication (F(4,195) = 2.87, p < 0.05). As well, the cognitive impairment level of the residents affected with whom they interacted. The higher the cognitive impairment level, the more interaction was directed toward the animal and less toward humans, regardless of visit type (F(2,101) = 4.10, p < 0.05). The dogs and the robot seal stimulated the residents to more in- teraction, compared with the toy cat, but the robot seal failed to maintain the attention at the same level over time. The cognitive functioning of the residents correlated with the level of interaction, and this needs to be studied further.

Olfaction: An Overlooked Sensory Modality in Applied Ethology and Animal Welfare

It has long been known that odors and olfaction play a major role in behavioral development and expression in animals. The sense of smell is employed in numerous contexts, such as foraging, mate choice, and predation risk assessment. Indeed, olfaction is the primary sensory modality for most mammals, and many domestic species kept by humans, including chickens (1). Odors are therefore likely to influence many of the handling and management procedures carried out with animals, whether on farms, in zoos, in the laboratory, or in the family home. Despite this, applied ethologists and animal welfare scientists have not to any great extent investigated chemosensory perception or included odors in their studies.

An exploratory study of competition scores and salivary cortisol concentrations in Warmblood horses

The main objective of this explorative study was to describe the relationship between competition scores and salivary cortisol concentrations in young horses during dressage and showjumping competitions. The study also investigated whether the diurnal rhythm of salivary cortisol concentrations was affected by competition over consecutive days compared with the home environment. Saliva samples were collected from 126 dressage horses and showjumpers in their home environment and at 3 different events. The relationship between scores given by judges at the competition and cortisol concentrations at the event was assessed. The results demonstrated that competition scores correlated positively to baseline cortisol concentrations at one of 3 events (r = 0.53, P < 0.001). Salivary cortisol concentrations followed a diurnal rhythm with the highest concentrations measured in the morning and the lowest in the evening, both at home and in the competition environment (P < 0.05). Salivary cortisol concentrations were greater during the competitions than at home (P < 0.05) except at one event where showjumpers did not increase between home and competition. Dressage horses had the highest baseline cortisol concentrations at competition, and exercise caused cortisol concentrations to increase in both showjumpers and dressage horses (P < 0.001). In conclusion, the diurnal rhythm in salivary cortisol concentrations was maintained in the novel environment. Dressage horses demonstrated greater baseline cortisol concentrations at competition than showjumpers, suggesting that they may perceive the novel environment as more stressful. Furthermore, there was no consistent relationship between baseline salivary cortisol concentrations and competition scores across the events.

The effect of shelter design on shelter use by Icelandic horses in the winter period

Abstract Little is known about the effect of shelter design on sheltering behavior in horses. This study investigates shelter use by Icelandic horses kept outdoors 24 hours a day during the winter in Denmark and whether shelter use and levels of fecal cortisol metabolites (FCMs) are affected by (1) the number of entrances (1 vs. 2) and (2) a partition inside the shelter. The effects of weather conditions on shelter use are also investigated. Thirty‐two Icelandic horses participated in the study. The horses were pastured in 8 groups of 4 horses, and each group had access to a shelter (30 m2), which in the first study period (5 weeks, Dec‐Jan) had either 1 or 2 entrances (n = 4 groups per treatment). In the second study period (5 weeks, Jan‐Feb), all shelters had 2 entrances and half were equipped with a partition inside the shelter (n = 4 groups per treatment). Infrared cameras were placed inside all shelters for recording of shelter use. Feces were collected weekly during the last 3 weeks of each study period. We found that groups with 2 entrances to their shelter used the shelters significantly more than groups with only 1 entrance (% pictures with at least 1 horse inside, median [25;75%]: 2 entrances: 12.6 [7;20] vs. 1 entrance: 3.0 [2;4], P = 0.029). In addition, horses with 1 entrance had significantly increased FCM levels (ng/g, mean ± SE: 2 entrances: 6.8 ± 0.5 vs. 1 entrance: 10.0 ± 1.2, P = 0.019). The partitions did not affect shelter use or FCM levels. In both study periods, the shelters were used mainly at night (light vs. dark hours: P < 0.001), and daily average temperatures below zero degree Celsius increased shelter use. We conclude that entrance conditions are crucial to the use of shelters by Icelandic horses during winter.

Social Learning in Horses—Fact or Fiction?

Prima facie, the acquisition of novel behaviors in animals through observation of conspecifics seems straightforward. There are, however, various mechanisms through which the behavior of animals can be altered from observing others. These mechanisms range from simple hard-wired contagious processes to genuine learning by observation, which differ fundamentally in cognitive complexity. They range from social facilitation and local enhancement to true social learning. The different learning mechanisms are the subject of this review, largely because research on learning by observation can be confounded by difficulties in interpretation owing to the looming possibility of associative learning infecting experimental results. While it is often assumed that horses are capable of acquiring new behavior through intra-species observation, research on social learning in horses includes a variety of studies some of which may overestimate the possession of higher mental abilities. Assuming such abilities in their absence can have welfare implications, e.g., isolating stereotypical horses on the assumption that these behaviors can be learned though observation by neighboring horses. This review summarizes the definitions and criteria for the various types of social transmission and social learning and reviews the current documentation for each type in horses with the aim of clarifying whether horses possess the ability to learn through true social learning. As social ungulates, horses evolved in open landscapes, exposed to predators and grazing most of the day. Being in close proximity to conspecifics may theoretically offer an opportunity to learn socially, however anti-predator vigilance and locating forage may not require the neural complexity of social learning. Given the significant energetic expense of brain tissue, it is likely that social facilitation and local enhancement may have been sufficient in the adaptation of equids to their niche. As a consequence, social learning abilities may be maladaptive in horses. Collectively, the review proposes a novel differentiation between social transmission (social facilitation, local, and stimulus enhancement) and social learning (goal emulation, imitation). Horses are undoubtedly sensitive to intra-species transfer of information but this transfer does not appear to satisfy the criteria for social learning, and thus there is no solid evidence for true social learning in horses.