Abstract: REASONS FOR PERFORMING STUDY: There is little information about the prevalence of gastric ulcers in Standardbred trotters and potential correlations between ulcers and various traits, e.g. age, sex, performance, temperament and feeding regimens, need further elucidation. OBJECTIVES: The prevalence of ulcers in the gastric squamous mucosa of Swedish Standardbreds was estimated and the associations between ulcer score and age, sex, performance, temperament and feeding regimens were determined. METHODS: Eighty Swedish Standardbreds in active race training, trained by 9 different trainers, underwent gastroscopy. Information on age, gender, status of training, performance over the last 4 months compared with the trainer's expectations before that period, behaviour, eating habits, feed type, bedding type, time spent outdoors per day and medical treatment during the last month was collected. Gastroscopy was performed and lesions in the squamous gastric mucosa were scored from 0 to 4 (0 = no lesions; 4 = > 5 lesions with haemorrhage, > 10 lesions with no haemorrhage, or a large area of diffuse loss of surface epithelium). RESULTS: Twenty-four (30%) of the horses had no lesions in the squamous mucosa, 22 (27.5%) had a score of 1; 21 (26.2%) score 2; 9 (11.2%) score 3; and 4 (5%) score 4. Horses that were in preparatory training and those that had raced during the last month were significantly more affected than horses that were fit for racing but had not raced during the last month, using a logistic regression model with trainer incorporated as a random effect. CONCLUSIONS: The study confirmed a high prevalence of ulcers in the gastric squamous mucosa of Standardbreds in race training. Of the studied parameters only status of training showed a significant association with gastric ulcers of the squamous mucosa. POTENTIAL RELEVANCE: Gastric ulceration is a common disease and diagnosis should be made by endoscopic examination of the gastric mucosa, since parameters such as age, gender, performance, behaviour, eating habits provide only weak clues as to which horses might be affected. Further studies are needed to determine the aetiology of the syndrome and to find ways to reduce, if possible, the frequency of gastric ulcers.

Abstract: The aims of the present field-based study were to investigate changes in fit horses undergoing acclimatisation to a hot humid environment and to provide data on which to base recommendations for safe transport and acclimatisation. Six horses (age 7-12 years) were flown from Europe to Atlanta and underwent a 16 day period of acclimatisation. Exercise conditions during acclimatisation (wet bulb globe temperature index 27.6+/-0.0 [mean +/- s.e.]) were more thermally stressful compared with the European climate from which the horses had come (22.0+/-1.8, P<0.001). Following the flight, weight loss was 4.1+/-0.8% bodyweight and took around 7 days to recover. Water intake during the day was significantly increased (P<0.05) compared with night during acclimatisation. Daily mean exercise duration was 72+/-12 min and the majority of work was performed with a heart rate below 120 beats/min. Respiratory rate (fR) was increased (P<0.05) throughout acclimatisation compared with in Europe, but resting morning (AM) and evening (PM) rectal temperature (TREC), heart rate (fC) and plasma volume were unchanged. White blood cell (WBC) count was significantly increased at AM compared with in Europe on Days 4 and 10 of acclimatisation (P<0.01), but was not different by Day 16. In conclusion, horses exposed to hot humid environmental conditions without prior acclimatisation are able to accommodate these stresses and, with appropriate management, remain fit and clinically healthy, without significant risk of heat illness or heat-related disorders, provided they are allowed sufficient time to recover from transport, acclimatisation is undertaken gradually and they are monitored appropriately.

Abstract: REASONS FOR PERFORMING STUDY: Serious injuries to horses and riders in horse trials (HT) and three-day events (3DE) are usually associated with falls of horses, which invariably involve falls of the riders. Many potential causes for these falls have been discussed. OBJECTIVES: The aim of this case-control study was to investigate the risk factors for horse falls on the cross-country phase of horse trials and three-day events. METHODS: Using retrospective data, significant risk factors identified with unvariable analysis (P value <0.2) were entered into a multivariable logistic regression model. Significant risk factors (P value <0.05) were included in the final model. RESULTS: It was revealed that a number of course, obstacle and rider variables were significantly and independently associated with the risk of falling. Falling was associated with obstacles sited downhill (Odds ratio [OR] 8.41) and with obstacles with ditches in front (OR = 5.77). CONCLUSIONS: The relationship between course variables and the risk of falling was characterised and showed a significantly increased risk with increasing numbers of jumps on the course and for jumping efforts later in the course. In contrast, after allowing for the total number of obstacles on the course, an increase in the total number of jumping efforts appeared to have a protective effect. A later cross-country start time was associated with a decreased risk of a horse fall. Amateur event riders were approximately 20 times more likely to fall than professional riders. POTENTIAL CLINICAL RELEVANCE: This study has identified a number of risk factors associated with horse falls and highlights areas that can be altered to improve safety in cross-country competitions.

Abstract: REASONS FOR PERFORMING STUDY: Determining the risk of fatality of Thoroughbred horses while racing is essential to assess the impact of intervention measures designed to minimise such fatalities. OBJECTIVES: To measure the risk of racehorse fatality in jump and flat starts on racecourses in Victoria, Australia, over a 15 year period and to determine proportional mortality rates for specific causes of death. METHODS: All fatalities of Thoroughbred horses that occurred during or within 24 h of a race were identified from a database. The risk of a start resulting in a racehorse fatality in all races and within flat and jump races, proportional mortality rates, population attributable risk, population attributable fraction and risk ratios were calculated along with 95% confidence intervals. Poisson regression was also performed to estimate risk ratios. RESULTS: There were 514 fatalities over the 15 year period; 316 in flat races and 198 in jump races. The risk of fatality was 0.44 per 1000 flat starts and 8.3 per 1000 jump starts (18.9 x greater). The risk of fatality on city tracks was 1.1 per 1000 starts whereas on country tracks it was 0.57 per 1000 starts. Of the 316 fatalities in flat races, 73.4% were due to limb injury, 2.5% to cranial or vertebral injury and 19.0% were sudden deaths. Of the 198 fatalities in jump races, 68.7% were due to limb injury, 16.2% to cranial or vertebral injury and 3.5% were sudden deaths. The risk of fatality in flat starts increased between 1989 and 2004 but the risk in jump starts remained unchanged over the 15 year period. CONCLUSIONS: The risk of fatality in flat starts was lower in Victoria than North America and the UK but the risk in jump starts was greater. Catastrophic limb injury was the major reason for racehorse fatality in Victoria but there was a larger percentage of sudden deaths than has been reported overseas. The risk of fatality in jump starts remained constant over the study period despite jump racing reviews that recommended changes to hurdle and steeple races to improve safety. POTENTIAL RELEVANCE: This study provides important benchmarks for the racing industry to monitor racetrack fatalities and evaluate intervention strategies.

Abstract: REASONS FOR PERFORMING STUDY: Overstrain injuries to the superficial digital flexor tendon (SDFT) and suspensory ligament (SI) are among the most common musculoskeletal injuries which contribute to the considerable wastage of racing Thoroughbreds. Many epidemiological studies have demonstrated the prevalence of and risk factors for tendon injury when racing but have not included those injuries sustained during training. However, since tendon injury during training is seen commonly in clinical practice, it is appropriate to determine the overall prevalence of tendon injury sustained during both training and racing. OBJECTIVE: To determine the prevalence of overstrain injury to the SDFT and SL during training and racing among Thoroughbred flat racehorses in Japan in 1999. METHODS: A retrospective study was performed using a sample population of 10,262 Thoroughbred racehorses. The medical information database of Thoroughbred racehorses registered by the Japan Racing Association (JRA) in 1999 was analysed for SDFT and SL overstrain injury diagnosed by a veterinarian employed by JRA during training and racing. Jump racehorses were excluded from this study. RESULTS: The prevalence of forelimb SDFT tendonitis and SL desmitis was 11.1% (1130 cases) and 3.61% (370 cases) of the population, respectively. In the hindlimb, there were 0.06% (6 cases) and 0.14% (14 cases), respectively. Risks of SDF tendonitis in the forelimb in 3-year-olds or older horses were significantly higher than in 2-year-olds. In contrast, the risk of SL desmitis in the forelimb at age 3 and 4 years was 2.23 and 2.11 times higher, respectively, than in 2-year-olds, but this increased to 5.07 times in those age > or = 5 years. Entire males were at greater risk in comparison to females and geldings. CONCLUSIONS: The results suggest that the prevalence of SDF tendonitis and SL desmitis in the forelimb was associated with the horse's age and sex. The prevalence of SL desmitis increased further with age compared with SDF tendonitis, possibly reflecting a more rapid accumulation of degeneration in this structure. POTENTIAL RELEVANCE: The age-related risk demonstrated in this study provides further support that overstrain injuries are associated with accumulated degeneration. These data provide a valuable resource for further research into the aetiology of tendon injury in the racehorse.