Abstract: Between March 1, 2000 and August 31, 2001, a case-control study was conducted on 12 racecourses in England and Wales to identify and quantify the risk factors associated with horse falls in hurdle races. The cases and controls were defined so that variables relating to the horse, the jockey, the race and racecourse, and the jump could be considered. The cases were defined as a jumping effort at a hurdle flight that resulted in a fall, and the controls were defined as a successful jump over a hurdle at any of the 12 racecourses within 14 days before or after the case fall. Conditional logistic regression was used to examine the univariable and multivariable relationships between the predictor variables and the risk of falling. The risk of falling was significantly associated with the position of the jump in the race, and with the distance and speed of the race. A horse's previous racing experience and history were also significantly associated with the risk of falling and horses participating in their first hurdle race were at almost five times greater risk of falling than horses that had hurdled before.

Abstract: Abstract Tölt is a symmetric four-beat gait with a speed range extending into that of trot and canter. Specific shoeing methods, such as unnaturally high and long hooves, are used to enforce individual gait predisposition. The aim of this study was to assess the consequences of this shoeing style on loading and movement of the limbs at walk, tölt and trot, and at different velocities. Simultaneous kinetic and kinematic gait analysis was carried out at walk (1.4 m/s) and at two tölting and trotting speeds (3.3 m/s and 3.9 m/s) on an instrumented treadmill. Thirteen sound Icelandic horses were first measured with high, long front hooves (SH) and, 1 week later, after trimming the hooves according to standard shoeing principles (SN). Comparing SH with SN, front hooves had 21 ± 5 mm longer dorsal hoof walls, and the shoeing material per hoof was 273 ± 50 g heavier. In all three gaits, gait quality, as it is currently judged, was improved with SH due to a lower stride rate, a longer stride length and a higher, but not wider, forelimb protraction arc, which were also positively associated with speed. Forelimb–hind limb balance remained unchanged, but limb impulses were higher. Apart from an increase of ⩽2.2% in the forelimbs at the faster speed of both tölt and trot, SH had little influence on vertical peak forces.

Abstract: Selegiline ([R]-[-]N,alpha-dimethyl-N-2- propynylphenethylamine or l-deprenyl), an irreversible inhibitor of monoamine oxidase, is a classic antidyskinetic and antiparkinsonian agent widely used in human medicine both as monotherapy and as an adjunct to levodopa therapy. Selegiline is classified by the Association of Racing Commissioners International (ARCI) as a class 2 agent, and is considered to have high abuse potential in racing horses. A highly sensitive LC/MS/MS quantitative analytical method has been developed for selegiline and its potential metabolites amphetamine and methamphetamine using commercially available deuterated analogs of these compounds as internal standards. After administering 40 mg of selegiline orally to two horses, relatively low (<60 ng/ml) concentrations of parent selegiline, amphetamine, and methamphetamine were recovered in urine samples. However, relatively high urinary concentrations of another selegiline metabolite were found, tentatively identified as N- desmethylselegiline. This metabolite was synthesized and found to be indistinguishable from the new metabolite recovered from horse urine, thereby confirming the chemical identity of the equine metabolite. Additionally, analysis of urine samples from four horses dosed with 50 mg of selegiline confirmed that N-desmethylselegiline is the major urinary metabolite of selegiline in horses. In related behavior studies, p.o. and i.v. administration of 30 mg of selegiline produced no significant changes in either locomotor activities or heart rates.

Abstract: Six ponies were used to investigate the effect of tolazoline antagonism of detomidine on physiological responses, behavior, epinephrine, norepinephrine, cortisol, glucose, and free fatty acids in awake ponies. Each pony had a catheter inserted into a jugular vein 1 hour before beginning the study. Awake ponies were administered detomidine (0.04 mg/kg intravenously [i.v.]) followed 20 minutes later by either tolazoline (4.0 mg/kg i.v.) or saline. Blood samples were drawn from the catheter 5 minutes before detomidine administration (baseline), 5 minutes after detomidine administration, 20 minutes before detomidine administration which was immediately before the administration of tolazoline or saline (time [T] = 0), and at 5, 30, and 60 minutes after injections of tolazoline or saline (T = 5, 30, and 60 minutes, respectively). Compared with heart rate at T = 0, tolazoline antagonism increased heart rate 45% at 5 minutes. There was no difference in heart rate between treatments at 30 minutes. Blood pressure remained stable after tolazoline, while it decreased over time after saline. Compared with concentrations at T = 0, tolazoline antagonism of detomidine in awake ponies resulted in a 55% increase in cortisol at 30 minutes and a 52% increase in glucose at 5 minutes. The change in free fatty acids was different for tolazoline and saline over time. Free fatty acids decreased after detomidine administration. Free fatty acids did not change after saline administration. After tolazoline administration, free fatty acids increased transiently. Tolazoline tended to decrease sedation and analgesia at 15 and 60 minutes postantagonism. Antagonism of detomidine-induced physiological and behavioral effects with tolazoline in awake ponies that were not experiencing pain appears to precipitate a stress response as measured by cortisol, glucose, and free fatty acids. If antagonism of an alpha-agonist is contemplated, the potential effect on hormones and metabolites should be considered.

Abstract: Glucocorticoids or their metabolites can be measured in several body fluids or excreta, including plasma, saliva, urine and faeces. In recent years the measurement of glucocorticoid metabolites (GCMs) in faeces has gained increasing attention, because of its suitability for wild populations. In horses, however, the group-specific enzyme immunoassay described so far has a limited racticability due to its complex extraction procedure. Therefore, we tested the applicability of
other enzyme immunoassays for glucocorticoid metabolites. The present study clearly proved that an enzyme immunoassay (EIA) for 11-oxoetiocholanolone using 11-oxoetiocholanolone-17-CMO: BSA (3&#945;,11-oxo-A EIA) as antigen showed high amounts of immunoreactive substances. Therefore it was possible to use just a small amount of the supernatant of a methanolic suspension of faeces. The results
correlated well with the already described method for measuring GCMs in horse faeces, i.e. analysing the samples with an EIA after a two step clean up procedure of the samples (Merl et al. 2000). In addition, the 3&#945;,11-oxo-A EIA has the advantage of providing a bigger difference between baseline values and peak values after ACTH stimulation. The new assay increased the accuracy of the test,
lowered the expenses per sample, and storing samples at room temperature after collection was less critical than with other assays investigated in our study. This is a big advantage both in the field of wildlife management of equids and in the field of equestrian sports and it shows the importance of choosing an assay which is in good accordance with the metabolites excreted in a given species.