Abstract: This article reviews the effects of diet on equine feeding behavior and feeding patterns, before considering the evidence that diet affects reactivity in horses. A growing body of work suggests that fat- and fiber-based diets may result in calmer patterns of behavior, and possible mechanisms that may underpin these effects are discussed. In contrast, there is little evidence that herbal- or tryptophan-containing supplements influence equine behavior in any measurable way. The role of diet in the development of abnormal oral behaviors, particularly the oral stereotypy crib-biting, is also reviewed, and suggestions for future work are presented.

Abstract: Coat clipping is a common practice in sport horses; however, timing, purpose, technique, and clips vary widely, as do the management and feeding of a clipped horse. The aim of this study was to collect data regarding common clipping practices. A questionnaire was published online in Germany and contained 32 questions. Four hundred ninety-eight people answered at least one question, and 373 individuals (7% male, 93% female; ages 14–59 years) completed all the questions. Clipped horses were predominantly used as sport horses (68%), and they were either clipped immediately before or during the winter season (88%) or year-round (7%). The clipping date was scheduled according to hair length (52%), sweat amount (47%), and drying time (47%). Participants primarily used two clips: the hunter clip and the blanket clip, both without clipping the head (23% each). The majority of the clipped horses wore a blanket day and night (> 90%). Future studies with observations in the field are needed to support survey data in an effort to develop welfare recommendations for clipping practices utilized with horses.

Abstract: Three horses (Equus caballus) with a history of performing cognitive tasks including discrimination learning, categorization, and concept use were tested to evaluate their long-term memory (LTM) in three experiments. In addition, use of LCD multi-displays for stimulus presentation was incorporated into cognition testing protocol for the first time with horses. Experiment 1 tested LTM for discrimination learning that originally occurred 6 years earlier. Five sets of stimuli were used and the two horses tested showed no decrement in performance on four of the sets; however, both horses did score below chance on one set. Experiment 2 examined long-term categorization recall 10 years after horses had demonstrated the ability to make stimulus selections based on shared characteristics within a given category. The horse tested for LTM after the decade-long interval immediately and consistently applied the previously learned categorization rule to not only familiar but also novel sets of stimuli. Experiment 3 tested another horse for LTM for a relative size concept. This horse had originally demonstrated concept rule use in order to select stimuli based on their relative size to one another. More than 7 years later and without further training, this horse reliably applied the previously established size concept to both familiar and novel sets of stimuli. These findings are the first reports of long-term categorical and conceptual memory in horses and are consistent with observations of domestic and wild horses, which indicate that behavioral and ecological events may be remembered for long periods of time. These studies also demonstrate the adaptive nature of horses with regard to their ability to generalize over several different testing conditions.

Abstract: Horses are likely to exhibit aggression when meeting for the first time. Therefore, this study compared 3 methods for mixing horses to evaluate their effectiveness in reducing aggressive interactions: (1) mixing pairs of horses in a paddock (P, 10 minutes, 15 tests), (2) introducing 1 unfamiliar horse to a pair of familiar, resident horses in a paddock (PP, 10 minutes, 15 tests), (3) allowing limited physical contact between pairs of horses for a short period of pre-exposure in neighboring boxes (B, 5 minutes, 16 tests) before mixing them in a paddock (BP, 10 minutes 16 tests). A total of 16 Swedish Standardbred mares, aged 6-18 years (mean age ± SD: 11 ± 4.4), were included in the study. Half of the horses were familiar with each other (resident horses, n = 8), whereas the other half were bought in from a variety of sources (unfamiliar horses, n = 8). Social interactions, consisting of behaviors from the sender, the receiver, and the subsequent sender's response, were recorded continuously as frequencies. There were no differences in the frequencies of aggressive behaviors between the 3 mixing methods, including those aggressive behaviors in which physical contact had been attempted (kick, strike). Although resident horses were overall more aggressive (median number of aggressive behaviors per horse, 62; Q1, 36; Q3, 68.5) than unfamiliar horses (median per horse, 4; Q1, 2; Q3, 12.5) during all tests (U = 97, P = 0.003), none of the 62 tests needed to be terminated. Unfamiliar horses did not receive more aggression from resident horses in PP (mean per test ± SD: 5.1 ± 3.1) than in P (mean per test ± SD: 6.4 ± 4.9) (t = 0.63, P = 0.544). However, the behavior “attack” was more frequent in PP (median per test, 2; Q1, 0; Q3, 5) than in P (median per test, 0; Q1, 0; Q3, 1) (U = 282, P = 0.042), and “flee” was more frequent in PP (median per test, 6; Q1, 4; Q3, 8) than in P (median per test, 1; Q1, 0; Q3, 6) (U = 290, P = 0.018). Pre-exposure in boxes did not reduce aggression in BP (median per test, 7; Q1, 4.3; Q3, 11.8) as compared with P (median per test, 6; Q1, 2; Q3, 16) (U = 264, P = 0.767), but during pre-exposure in B tests, horses exchanged more nonaggressive (median per test, 2; Q1, 0.3; Q3, 4) than aggressive (median frequency of aggressive behavior, 0; Q1, 0; Q3, 1) (W = 71, P = 0.013) and mixed interactions (median per test, 0; Q1, 0; Q3, 1) (W = 92, P = 0.016) through the opening. Results suggest mixing an unfamiliar horse with 2 resident horses at the same time instead of one by one may be preferable. In this way, the total aggression received by the unfamiliar horse will potentially be less, even though aggressive interactions may be more intense.

Abstract: Housing conditions for horses impose various levels of confinement, which may compromise welfare. Lying behaviour and activity can be used as welfare indicators for domestic animals and rebound behaviour suggests a build-up of motivation resulting from deprivation. The objective of this study was to determine if activity and lying behaviour of horses are affected by housing conditions and to investigate the occurrence of rebound behaviour after release from confinement. Eight horses were subjected, in pairs, to each of four experimental treatments; paddock (P), fully stabled (FS), partly stabled (PS) and yard (Y). Each horse received 6 days acclimatisation prior to the 24 h recording period. Time spent in lying and activity were electronically recorded using a tilt switch and motion sensor connected to a data logger worn on the horse's left foreleg. Time spent active during the first 5 min of release from stable to paddock in the PS treatment (days 1 and 5) and at the same time of day in the P treatment was used as a measure of rebound behaviour. Effect of housing conditions on total time spent active was highly significant (FS = 123 s, PS = 158 s, Y = 377 s, P = 779 s, P < 0.001). Housing conditions did not significantly affect total time spent lying (P = 0.646). Horses were significantly more active, compared with baseline paddock behaviour, on release from stabling on both days 1 (P = 0.006) and 5 (P = 0.025) of PS treatment. These results suggest that activity patterns of horses, but not lying behaviour, are affected by the housing conditions tested and that rebound activity occurs in horses after a period of confinement.