Abstract: A behavioural study of feral horses was conducted on the Pryor Mountain Wild Horse Range in the western United States. All 270 horses on the Range were identified individually. The sex ratio was nearly balanced. Foal to adult female ratio was 43-2:100. Morality was concentrated among foals and old horses. Horses were organized as forty-four harem groups each with a dominant stallion, one to two immature stallions, one to three immature mares, one to three adult mares and their yearling and foal offspring, and 23 bachelor groups of one to eight stallions. Harem groups were quite stable year-round because of dominance and leadership by the stallions and group fidelity by mares and their offsring. Most changes occurred during the breeding season and involved immature females. Defeat of dominant stallions was infrequent. Immature males were tolerated because of their submissive behaviour. Bachelor stallion groups were inherently unstable. Mares came into heat after foaling in May/June, and were mated by harem stallions only.

Abstract: Pitch processing is lateralized to the right hemisphere; linguistic pitch is further mediated by left cortical areas. This experiment investigates whether ear asymmetries vary in brainstem representation of pitch depending on linguistic status. Brainstem frequency-following responses (FFRs) were elicited by monaural stimulation of the left and right ear of 15 native speakers of Mandarin Chinese using two synthetic speech stimuli that differ in linguistic status of tone. One represented a native lexical tone (Tone 2: T2); the other, T2', a nonnative variant in which the pitch contour was a mirror image of T2 with the same starting and ending frequencies. Two 40-ms portions of f0 contours were selected in order to compare two regions (R1, early; R2 late) differing in pitch acceleration rate and perceptual saliency. In R2, linguistic status effects revealed that T2 exhibited a larger degree of FFR rightward ear asymmetry as reflected in f0 amplitude relative to T2'. Relative to midline (ear asymmetry = 0), the only ear asymmetry reaching significance was that favoring left ear stimulation elicited by T2'. By left- and right-ear stimulation separately, FFRs elicited by T2 were larger than T2' in the right ear only. Within T2', FFRs elicited by the earlier region were larger than the later in both ears. Within T2, no significant differences in FFRS were observed between regions in either ear. Collectively, these findings support the idea that origins of cortical processing preferences for perceptually-salient portions of pitch are rooted in early, preattentive stages of processing in the brainstem.

Abstract: Solving horse nutrition challenges require contributions from Psychology, Biology, Agriculture, and Veterinary Medicine because these are biological challenges of an anthropological nature. The domesticated horse has shifted from an animal of war, transportation, and farmwork, to a companion enjoyed for sport, leisure and recreation. The first realization and responsibility must lie in the fact that it is the owners and managers which are the source of many of the horses’ challenges. Nutritional challenges include: defining requirements and absorption of nutrients, improving feed efficiencies for performance, improving feeding management and eating behaviors, and preventing or treating clinical problems. These challenges can be addressed through science, horse management, and education. Many of today’s challenges in horse nutrition can be related to the equine genome and genetics. Those that can be addressed with nutritional consequences include Polysaccharide Storage Myopathy, Equine Metabolic Syndrome, Recurrent Exertional Rhabdomyolysis, Glycogen Branching Enzyme Deficiency, Hyperkalemic Periodic Paralysis, and Development Orthopedic Disorders. It is the scientific understanding of cellular processes in relation to nutrients which address the symptoms associated with these diseases. Consequently, feeding management can be changed to actually treat the disease. The most recent advances in equine nutrition implement the use of molecular and cellular based techniques to understand how nutrients are needed during times of stress, feed withdrawal and to maintain gut health. For example, the absorptive capacity and transporter gene expression and localization, are now being quantified. We are also now assessing the impact of the loss of reproductive endocrines on calcium and phosphorus homeostasis in the horse. Additionally, bioluminescent pathogenic bacteria have been utilized to view attachment rates in the gastrointestinal tract of the horse. These are merely examples of the approaches of science to these nutritional challenges. Science is of little use unless it is incorporated into improved management of horses. Every type of horse requires different management and good husbandry. In our country, 70+% of the horses are kept in small herds, on limited acreage, and used for recreation and sport. Since we have taken the horse out of its natural environment and subjected it to these roles, we now seek to determine ways to feed the horse in our environments; i.e. obesity, inconsistent exercise, confinement, surgery, competition, diseases. Private horse feed agribusinesses have aggressively positioned excellent products with claims to improve health, reproduction, performance, and even horse happiness. Owners and managers seek unbiased science upon which they ultimately make their own decisions. General challenge categories seem to be feeding geriatric horses, active performance horses, and idle horses with secondary metabolic problems. Thus, feeding recommendations include the determination of specific horse nutrient requirements, maximization of available forages, providing other nutrients, and exercise to manage horses more as horses. Private and public companies and Extension systems exist to provide online and other sources of information. As more and more people own horses as a hobby and for recreation, they share responsibility to inform themselves on how to best feed and care for their horses.

Abstract: The design of a captive environment should facilitate the expression of the natural behavioural repertoire of the species concerned. The domestic horse (Equus caballus) is a social, herd dwelling species that is often housed in isolation from con-specifics or kept in groups in paddock enclosures. Although the latter allows for social interaction and does not restrict movement per se, it may not promote natural activity patterns or group cohesion. The aim of the current study was to assess the impact of two different paddock designs on the behaviour of a stable group of horses (n=6: 2 mares, 4 geldings).
The paddock designs tested were adjacent and grassed similarly, but configured differently. A central paddock (75 x 75m) designated NT, was surrounded by a track 1.6-5.5m wide, designated T. The horses were turned out in their group into T or NT for 3 consecutive days. Their behaviour was recorded for one hour three times each day (10.00, 13.00, 16.00 hrs). Within each observation period of one hour focal sampling was used, each individual horse being observed for a 10 minute period. They were then moved to the other enclosure type for a further 3 consecutive days, followed by a repeat of each condition. When turned out the horses were fitted with a global positioning system device (Garmin Forerunner 305) to monitor distance travelled and speed for the period 10.00-17.00 hrs. The mean percentage of time spent in each behavioural state (standing alert, standing resting, walk/trot, grazing, lying, social interaction) during the periods observed was calculated. Behaviour during social interactions was classified as either affiliative (approach, follow, friendly contacts, mutual grooming) or agonistic (approach and retreat, bite, chase, head threat).
The horses travelled significantly further in T than in NT (paired samples t-test: t (5) = 11.74, p<0.001) and moved significantly faster (Wilcoxon signed rank test: z = -2.21, p=0.03). See Table 1. When the percentage of time spent in each behavioural state in T and NT was compared some significant differences were found. A significantly higher percentage of time was spent active (walking /trotting) in T than in NT (paired samples t-test: t (5) = 5.74, p=0.002). Standing alert was only recorded in T (paired samples t-test: t (5) = 3.48, p=0.02). A significantly higher percentage of time was spent grazing in NT than in T (paired samples t-test: t (5) = -3.58, p=0.016). Significantly more social interaction occurred in T than in NT (paired samples t-test: t (5) = 5.93, p=0.002). See Figure 1. In T, 91% of social interactions were affiliative and 9% agonistic, whereas in NT 29% were affiliative and 71% agonistic. No difference was found in the percentage of time spent standing resting or lying down in T and NT.
The benefits of housing horses in groups as opposed to individually have been demonstrated in previous studies. In addition to better satisfying the behavioural needs of the horse it has been found that group housed horses adapt more easily to training and display less undesirable behaviour than those housed individually (Rivera et al. 2002; Søndergaard and Ladewig 2004; Visser et al. 2008). However, individual housing is frequently selected by horse owners in preference to group housing to avoid the risk of injury during agonistic encounters. Fureix et al. (2012) suggest that management practices may well contribute to aggressiveness in horses and that the conditions under which we keep horses should be reviewed. The findings of the present study indicate that the design of the enclosure in which groups of horses are kept affects the nature of social interactions. The T paddock design resulted in reduced intra-group aggression. However, this paddock design also reduced the time spent grazing and increased vigilant behaviour. Although the results demonstrate that a paddock system including tracks may facilitate group cohesion and more natural movement patterns, the long-term impact on behaviour and welfare requires further investigation.
References:
Fureix C, Bourjade M, Henry S, Sankey C, Hausberger M. (2012). Exploring aggression regulation in managed groups of horses (Equus caballus). Applied Animal Behaviour Science 138: 216-228.
Rivera E, Benjamin S, Nielsen B, Shelle J, Zanella AJ. (2002). Behavioural and physiological response of horses to initial training: the comparison between pastured versus stalled horses. Applied Animal Behaviour Science 78: 235–252.
Søndergaard E, Ladewig J. (2004). Group housing exerts a positive effect on the behaviour of young horses during training. Applied Animal Behaviour Science 87: 105-118.