Abstract: The use of molecular techniques has increased our understanding of biological systems; in particular how genes and proteins operate within a cell or organ in response to various stimuli. These techniques can be used to study modes of action or mechanisms in disease states, or in response to applied management or nutritional changes. While applied and basic research are often conducted independent of one another, the real advantages to the equine industry will come from the use of molecular techniques to address applied challenges and/or opportunities within the industry. Therefore, the overall goal of our research has been to use basic and molecular tools to investigate modes of action resulting from changes in nutrition or management. We investigated active nutrient transport capacities of the small and large intestine, the effects of feed withdrawal on intestinal transporter gene expression and function, as well as other measurements pertaining to gut health (gut barrier function and gastrointestinal morphology). This novel and thorough approach to characterize sectional differences (fore- and hind- gut) of nutrient absorption has resulted in quantitative measures of active transport capacity for glucose, phosphorus, glutamine, lysine, and di-peptides in the horse. This research demonstrates that by-products of fermentation in the cecum such as microbial proteins and hydrolyzed phytate phosphorus, can be absorbed in the colon. Previously unidentified in the hindgut of the horse, we reported the expression of the di-and tri-peptide transporter, PepT1, as well as the neutral amino acid transporter, ASCT2, and transport of their substrates. We observed that nutrient transporters for glucose (SGLT1), glutamine (ASCT2) and for di-peptides (PepT1) can be regulated by diet, implying biological relevance to feeding management strategies. Feed withdrawal in horses pre- or post-surgery, prior to or during horse shows, during transport, or for other management reason is common. It is therefore important to understand how the removals of nutrients impacts gut health and/or disease susceptibility. The use of molecular techniques has provided a basis for the roles of certain core nutrients during times of feed withdrawal. For example, nutrients such as glutamine play a major role in proliferation and repair in the gut, serve as a major energy substrate, and may provide a means of assessing nutritional stress in the gut. Recent data concludes that following a feed withdrawal, the need for glutamine increases up to 116% in the proximal jejunum, and the gene expression of its transporter (ASCT2) increases by 78%. Additional studies utilizing molecular techniques to address nutritional challenges in the horse include how hormone loss due to ovariectomization impacts the homeostatic regulation of calcium and phosphorus in the horse. To improve nutrition and feeding management practices in horses, knowledge regarding how and where nutrients are absorbed, utilized and regulated under varying physiologic stressors (disease, exercise, reproductive status, etc.) is needed. The integration of applied and basic research facilitates a better and more complete understanding of mechanisms underlying common health and nutritional challenges facing the equine industry.

Abstract: Horses provide an interesting animal model to test short- and long-term effects of the paternal influence on the offspring under natural conditions. As a highly social animal, horse naturally is living in long-term harem groups building strong familiar bonds. Arguing that the environment of a juvenile is highly important for the development of cognitive and social functions as well as for the emotional competence, a future study on domestic horses wants to highlight the paternal influence on the offspring as well as special effects of the stallion during the first two years of the foals´ life. Nowadays, in most husbandry systems it is still common to keep the stallions separated, raising the offspring in an intact harem group is very rare. The aim of this study is to describe the role of the stallion in the early development of the foal in an extensive pasture management system living in natural harem groups. Results are going to be compared to findings of studies on groups without the male present in the rearing phase. A precise behavioural analysis is planned; direct behavioural observations are going to be supported by long-term and continuously activity measures by special telemetry collar systems. Additional physiological measures should give evidence of the investment of the stallion. The young horses will be confronted with different tests of cognitive and social abilities (exploration behaviour, fear behaviour, play behaviour). The results of this study will contribute to fundamental research in the behaviour of the horse and might display an important step to animal welfare in modern horse husbandry. It will be possible to set a time-frame in which the male does have positive influence on the offspring and therefore should be kept with the family. A detailed knowledge of the influence of the male to cognitive and social abilities could as well be applicable in the training of horses and therefore be of great importance in equestrian sports.

Abstract: Horses maintain the social structure through the establishment of dominant-subordinate hierarchical relationships, both within and between groups. The object of study was the feral horse population, living on the Vodnyi Isl, Manych-Ghudilo Lake, on the territory of Rostov Region, S Russia the State Nature Biosphere Reserve “Rostov”. The social structure of this population is represented by the harem and bachelor groups, and their variety – the “mixed”groups, the presence and composition of which is atypical for the populations of feral horses. The main objectives of this work were to identify the hierarchical structure of different types of social groups and the role of the stallions in them, defining the dominance rank of animals. The method of continuous logging occurred aggressive reaction, ritualized interaction between stallions, take into account the direction of interactions between individuals. We observed 5 harem, 3 bachelor and 3 mixed groups. Each group was studied for a total of 60 h (8 h per group per days).Behavioral observations were carried out in summer 2009-2011. Based on the number and direction of aggressive interactions the hierarchical coefficient was calculated for individual horses (Ivanov et al, 2007). Harem group consists of an adult stallion (<5 years old) and a few mares with their offspring. Our observations of harem groups confirm the previously known information about this type of social groups (Berger, 1986; Carson, Wood-Gush, 1983, Keiper, 1983). Hierarchical system between mares is close to linear with reversal. The stallion is not included in the hierarchy of the mares; he is the leader and serves to maintain the integrity of the group and inter-group hierarchy, and has reproductive function. Bachelor groups consist of stallions 2-3 years and older who do not have their own harem. It is known that dominance hierarchy in these groups is linear, young males or males who recently had joined the group have low ranks (Berger, 1977; Houpt, Keiper, 1982; Kirillov Paklina, 1990). In observed bachelor groups dominant stallion have a significantly higher rank in the hierarchy. However, among other stallions is not always observed strict linear hierarchy – some individuals have very similar ranks. Function of managing the group and maintaining the intergroup hierarchy can be distributed among the all stallions in the group. Mixed groups are composed of several mature stallions, one or more mares (sometimes with the offspring). In the study population in this type of social groups animals may be mature (age 5 and older) and semi-mature (2-5 years). The hierarchy of these atypical groups has not been studied. In the studied 3 mixed groups stallions have very similar hierarchical rank, dominant and subordinate stallions share a function of managing the group, participation in ritualized interactions. Our studies have revealed the plasticity of the hierarchical structure of groups of horses and the need to further investigate the distribution of social roles among stallions.

Abstract: We observed the activity and movements of Konik horses (Equus caballus) in order to determine the initiators of movements and the individuals taking the lead in movements of the main groups. We conducted our observations between March-June 2010 along the shores of the Rhine river, in the Blauwe Kamer reserve, in the Netherlands. The horses were introduced to the reserve alongside with cattle to prevent the growth of the forest and maintain the grass habitat. We videotaped all observations on two digital video cameras, one providing the general view of the group and the other scanning and focusing on the individuals, to aid with identification. Horses were recognized based on individual profiles that were created for each one, consisting of photos of both sides and notes of the main characters, such as orientation and coloration of the mane, prominent scars and markings, etc. Twenty three horses (not counting foals) were organized in two harem groups with 11 individuals (two of which were dominant stallions) in the large group and six individuals (one of which was a stallion) in the second group. These two main groups were always within sight of each other, and two bachelor males moved usually in their vicinity. An additional group of three young bachelor males roamed elsewhere in the reserve. We divided the movements of the horses to local movements while grazing and to long-distance movements, in which the horses moved to a different grazing location, to a pond of water, resting area or groups of trees that were used by the horses for scratching themselves. During the local movements, any two of the three oldest females in the large harem group were enough to cause the whole group to follow them and gradually change position within the pasture. The smaller harem always followed the large harem’s movements. The long-distance movements of the large harem were sometimes initiated by one of the harem stallions that herded their group and at other times – by the oldest females. Soon after the movement was clearly initiated, the dominant stallions positioned themselves in the back of the group or in the center and had no influence on the direction of move that was only determined by the leading females. In the long-distance movements too, the small harem followed the large harem group, and the two bachelor males usually followed behind them. Social interactions included aggressive interactions between the two dominant males within the large harem or between dominant stallions and the two bachelor males accompanying the two harems. In addition, dominant males courting or attempting to mate with mares sometimes caused a turmoil that eventually initiated movement of the harems. KW -

Abstract: We tested untrained horses (foals and breeding mares) in 3 different breeding centres. Horses were kept in a pasture during daytime in bigger groups (median 12, min: 6, max 35 / pasture) according to age, gender and breed (hungarian halfbred, hucul, arabian and thoroughbred). To measure their reactions to an unfamiliar person we conducted an active and a passive human test. In the active human test the test person (TP) approached a focal animal in the group from a predetermined direction: from their front, from their side (left or right) or from the rear. As TP reached the horse (of app. 0.5 m distance), she tried to pet the animal’s head. The TP always chose and approached a standing or a grazing horse (ie. those that were not walking, galloping, playing etc.). The horse’s reaction to the approaching human was scored 1-5. Score 1: the horse moved away and the TP could not even approach it within 0.5 m; Score 2: the horse made max. 2 steps away, but could be reached and petted; Score 3 and Score 4: the horse stood in its place but showed different signs of discomfort (head turn – Score 3; backing ears, tail slash – Score 4); Score 5: the horse stood and did not show any sign of discomfort or actively approached the TP. There was no significant difference in the horses’ reaction between approaching from their left or right side. Approaching from their front or from their side (left or right) did not differ significantly either. However, the odds of walking away from the TP (score 1 or 2) was 2.7 (Fisher-test, p=0.039) and 3.3 (p=0.012) times higher when TP approached from the rear compared to approaching from their front or from their side (left or right), respectively. In the passive human test the TP stood immobile for 4 minutes in 5 or 10 m far from the horses during their active (grazing) or inactive (standing idle during noon) period. Horses approached TP significantly sooner (general linear model, p=0.017) when she stood 5m distance (38 ±63 s) compared to 10m (97 ±52 s). The arrival of a second horse after the first horse approached the TP showed significant high correlation with the latency of the first horse arrival (Pearson correlation, r=0.96, p<0.001). The horses were less keen (p=0.008) to approach the human when they were tested in an inactive period (177 ±110 s) compare to active period (38 ±63 s).