Abstract: A number of discrimination learning studies suggest that horses attend to spatial cues in preference to visual ones. However, global and relative spatial cues have generally been confounded so it is not clear what information horses actually used. There has also been no study of whether one cue is learnt at the expense of another, or whether multiple cues are encoded but prioritised differently. We therefore carried out a series of studies examining how horses use different cues in learning a food-finding discrimination task. All studies used a criterion for success of 7/10 on two consecutive days (binomial test, p=0.0004).
A pilot study showed that horses could discriminate between three buckets using visual cues (striped, chequered or plain patterns). All four subjects performed significantly above chance levels, although one horse’s performance did not meet the criterion. Three others completed the task in between two and 12 sessions. There were some indications that horses tried to solve the task using irrelevant spatial information.
Nine foals were then taught to find a food reward using the same three patterned buckets placed in a row in any corner of a test arena. In Stage 1 the rewarded bucket was signified both by visual cues (pattern) and by relative spatial cues (left, middle or right position). Foals took between 2 and 10 days to complete the task , whereupon the cues were separated. Foals then had to ignore the inappropriate cue in Stage 2. For the Spatial group (n=5), only relative position remained relevant; for the Visual Group (n=4) bucket pattern indicated the rewarded bucket. Spatial group foals completed Stage 2 faster than Visual group foals (Mann Whitney U, z=-2.71, p=0.008). Position cues seemed to overshadow learning about visual cues: Visual group foals persisted in responding to the previously correct position and none reached criterion within the maximum available time (15 days to complete both stages).
Finally, five adult horses and one 10 month old filly learnt to find a reward in one of three identical yellow buckets whose position in an array (left, middle or right) and location within the test arena were consistent. On reaching criterion, responses were recorded in two unrewarded probe trials where the buckets were either shifted along the same axis or rotated by 90º. When the array was shifted, five out of six horses chose the previously correct position (binomial test, p=0.018) that was now in a new location within the school. Choices were not significantly different from random when the array was rotated, suggesting that the horses had learnt something about global cues even if they did not use them in selecting a bucket.
At the small scale tested, relative spatial cues (position with regard to other goals) seemed to be more important to horses than either visual cues or global spatial cues, though the latter appeared to be encoded to some extent. Reliance on spatial cues may reflect their usefulness in the horse’s natural lifestyle in navigating over long distances and feeding on visually similar plants.

Abstract: The Humane Society United States (HSUS) has been partnering with several prominent researchers for over 20 years to assess the potential use of Porcine Zona Pellucida (PZP), a protein used as a fertility control vaccine for wild horses. Past studies on herds located on barrier islands of the eastern United States have demonstrated that PZP prevented pregnancies and was a valuable tool for population management. With the generous support of the Annenberg Foundation and in partnership with the Science and Conservation Center, Tufts University and The University of Toledo, HSUS is conducting a 5-year longitudinal study to assess the effectiveness of immunocontraception on over 600 wild horses in the western United States.
This project involves 2 herds of over 300 wild horses each located in Utah and Colorado. We began gathering pre treatment data in April 2008. Birth rates, band size, and individual horse identifications were recorded. In the winter of 2008/2009 both herds will be captured and all mares that are released will be treated with a 2-year-duration PZP vaccine. Both herds will be closely monitored for reproduction and behavior changes for 3 years. We will record the differences in reproductive success of treated and untreated (not captured) females.
HSUS is also seeking to develop refinements to the PZP vaccine and delivery technologies. HSUS is currently trying to improve the production of the PZP vaccine by producing it with techniques that are more efficient and less costly. Improving delivery methods for the 2 year drug is another goal of this research that may allow herd managers the flexibility of treating mares year round without having to capture it. HSUS also hopes to demonstrate that incorporating this new delivery method and proactively managing wild horse herds will assist in maintaining wild horse populations at a level that is sustainable and manageable.

Abstract: Earlier research indicates that stallions might either prevent social interactions between mares in their
herds directly or indirectly by their presence (Feist and McCullough, 1976; Sigurjonsdottir et al.,
2003) The impact of stallions on the social interactions between harem members was studied in 6
groups of Icelandic horses in 2004, 2006 and 2007 for altogether 525 hours. Four of the groups were
permanently living together under semi-feral conditions, while two were temporary breeding groups. In
addition, temporary and permanent groups were compared and the effect of the stability of the group
on the social behaviour of horses was investigated .
The results show that stallions seldom intervene directly in social interactions between harem
members. However, the hierarchies were less rigid and fewer friendship bonds were found in the
groups compared to what has been found in groups without stallions in Iceland. These results give
some support to our prediction that the stallion does indirectly suppress social interactions of herd
members.
The stability of the group was found to affect the aggression rate, since a higher aggression rate was
found in the temporary groups compared to the permanent groups. The number of preferred
allogrooming partners of the horses was also affected to some extent, as a significantly lower number
of allogrooming partners was found in the most unstable group compared to all the other groups. The
results have significance for further research in the field of social structure of mammals, and may also
be applied in the management of horses and other domestic animals.

Abstract: Aim of study was to investigate the effects of transport stress on thyroid response, body weight, rectal temperature and heart rate changes in one hundred twenty-six healthy stallions in basal conditions, before and after short road transport. One hundred twenty-six Thoroughbreds and crossbreds stallions with previous travelling experience, aged 4 to 15 yr, were transported by road in a commercial trailer for a period of 3 h (distance <300 km). Blood samples and physiological parameters were collected at 0800 (basal I) and at 1100 (basal II), in each horse“s box, one week before the loading and transport in basal conditions, and one week later, at 0800 immediately before loading (pre-transport), and after 3 h period of transport and unloading, on their arrival at the breeding stations (post-transport), in each new horse”s box, within 30 min. Increases in circulating T3, T4 and fT4 levels (P < 0.01), but not for fT3 levels, were observed after transport, as compared to before loading values, irrespective of different breed. Lower T4 and fT4 levels were observed in basal II (P < 0.01) than basal I and before loading values (pre-transport). After transport Thoroughbreds showed higher fT3 (P < 0.05) and fT4 (P < 0.01) levels than crossbred stallions. No significant differences for T3 and T4 changes were observed. A significant increase in rectal temperature (P < 0.01) and heart rate (P < 0.05) was observed after transport, as compared to before loading values (pre-transport). No differences between basal I, basal II and before loading values (pre-transport) for physiological parameters were observed.
The highest T3, T4 and fT4 levels recorded after short transport seem to suggest a preferential release from the thyroid gland. The results indicate that short road transport stress contributes significantly to thyroid hormone changes, according to different breed, and to the increase in rectal temperature and heart rate. No differences related to different age were observed.

Abstract: Standard horse trailers, adapted from dead-weight delivery wagons, were never intended to carry live weight. Horse magazines and scientific, veterinary, animal behaviour, and engineering journals indicate the consequences: scrambling, trailer sway, equipment damage, loss of tow vehicle control, jack knifing, rollovers, and injuries to horses, handlers, and rescuers. The standard horse trailer cannot meet motor vehicle regulations requiring trailers to halt within 9 metres (30 feet) at 32 kilometres (20 miles) per hour without jack knifing. Equipment intended to protect the horse in transit adds to travel hazards. University of Guelph Ontario Veterinary Clinic surgeons report that head, throat, chest, shattered shoulder blades, butt bar or chain injuries to hocks and legs, and pastern injuries, in that order, are common. Internal, back, and hindquarter injuries also result due to the horse“s forced high-headed, wider hindleg stance or falling during transport. The horse”s sacroiliac joint, not intended to be weight bearing, is easily dislocated by pathologists. This is why for centuries horsemen have released tension from horses“ backs and necks by ”showing them the way to the ground.“ It was Italian cavalryman Federico Caprilli”s forward seat which removed strain on the horse“s hindquarters and freed its head to balance. More demanding jumps, slides and races were possible. Today, only two horse transport designs allow the horse to balance automatically and naturally during transit. Strain on the horse”s hindquarters is removed. These transports, adapted to equine behavioural needs, meet Office International des Epizooties (OIE) standards for handler and horse safety and welfare, and automotive safety. Japanese and U.S. studies on performance horses transported according to OIE standards have indicated that these horses have a competitive advantage. Applying these standards allows a horseman to complete a journey with the same horse that began it.