Abstract: Although horses are social animals they are often housed individually with limited social contact to other horses and this may compromise their welfare. The present study included eight young female horses and investigated the strength of motivation for access to full social contact, head contact and muzzle contact, respectively, to a familiar companion horse. Horses were housed individually next to their companion horse and separations between pens prevented physical contact. During daily test sessions horses were brought to a test area where they could access an arena allowing social contact. Arena access during 3 min was given after completion of a predetermined number of responses on a panel. Fixed ratios (FR) of 8, 16, 24, 32 and 40 responses per arena access were applied in a random order, one per daily test session, within each test week (Monday to Friday), and the number of rewards per daily test session was recorded. All horses could access all three types of social contact in a cross-over design, and an empty arena was used as control. Motivational strength was assessed using elasticity of demand functions, which were estimated based on the number of rewards earned and FR. Elasticities of demand for the three types of social contact were low (-0.20), and not significantly different, although increasing FR still resulted in a decrease in rewards obtained for all three types of social contact (P < 0.001). Across FR-levels horses earned more rewards for social contact than for an empty arena, as shown by much higher intercept values (2.51 vs. 0.99; P < 0.001). However, the elasticity of demand for infrequent access to an empty arena (-0.08) was lower than for social contact (P < 0.01) and not significantly different from zero (P = 0.07). Horses performed more social behaviour the lesser the restriction on social contact (full > head > muzzle). However, the finding that horses showed a similar and high motivation for all three types of social contact suggests that they are valued equally highly in a situation where the alternative is no social contact.

Abstract: The behaviour of humans around horses is thought to have a substantial impact on how people are perceived in subsequent interactions and many horse trainers give detailed advice on how handlers should behave when initially approaching a loose horse. Here we report on three studies designed to explore the effect of different human approach styles on the behaviour of naïve and experienced horses. In the first study, the change in flight distance (distance at which horses started to avoid an approaching human) of twelve semi-feral Dartmoor ponies, undergoing training to allow handling, was assessed. Over the 10 handling sessions median flight distance decreased significantly (p < 0.001) from 2.38 m to 0.00 m and there was a significant positive shift in the ponies' behaviour following the appearance of the researcher (p = 0.002). In a second study the effect of a direct (vigorous, swinging a lead rope and with eye contact) versus indirect (relaxed, no rope swinging and without eye contact) approach style was assessed on six adult experienced riding horses. The mean flight distance during a direct approach style (6.87 m) was significantly greater than that which occurred during an indirect approach style (2.32 m). Direction of approach was not found to significantly affect flight distance. In a third study, the effect of the rope was removed and a similar method to the second study applied to a group of naïve, feral ponies. The effect of different components of approach style, speed of approach, handler body posture and direction of gaze, which might contribute to observed differences in behavioural responses, were then examined systematically in this population. This revealed no significant difference in mean flight distance between the two approach styles (2.28 m indirect versus 2.37 m direct approach), but ponies were significantly more likely to move off in trot (p = 0.025) and to travel further (p = 0.001) when a direct approach was used. Speed of approach was the most salient factor, with a fast approach increasing both the tendency to move off in trot (p < 0.001) and distance travelled (p < 0.001). Body posture (relaxed or tense) had no effect, while flight distance was significantly greater when the person was looking away (p = 0.045). These results suggest horses may have an important egocentric spatial barrier, which perhaps relates to personal space and triggering of the flight response. Contrary to popular belief, body posture did not appear to be very important in the contexts examined unless accompanied by extraneous aids, while the speed of approach is particularly significant. These results are of important practical relevance in reducing the risk of injury, and the effective management of horses with minimal stress.

Abstract: Abstract Concentrated feed diets have been shown to drastically increase the rate of the cribbing, an oral stereotypy in horses, but the specific component causing the rise has not been identified. Furthermore, the mechanism through which feed affects cribbing has not been explored. In the first experiment of this study, we quantified the latency to crib and number of cribs in 15 min after the horses tasted various grain, sugar, and artificial sweetener solutions. Undiluted grain stimulated the most cribs (P < 0.01) compared with all other solutions, and shortest latency to crib, although this was significantly higher only when compared with diluted grain (P = 0.03). In Experiment 2, latency to crib and number of cribs in 15 min after the grain and sugar solutions were administered via nasograstric tube were also evaluated. There were no statistical differences among cribbing responses to grain, fructose, and water administered directly to the stomach although grain stimulated cribbing behavior more quickly than 10% fructose (P = 0.03) and 100% tap water (P = 0.04). These results confirm that highly palatable diets, possibly mediated through the opioid and dopaminergic systems, are one of the most potent inducers of cribbing behavior. The highly palatable taste remains the probable “cribogenic” factor of concentrated diet, although gastric and post-gastric effects cannot be excluded.