A prospective study on fitness,workload and reasons for premature training ends and temporary training breaks in two groups of riding horses

Little is known about wastage in riding horses and the factors like fitness and workload that may reduce injuries and maximise welfare. To evaluate fitness, workload and reasons for premature training ends (PTEs) and temporary training breaks (TTBs) during a nine week training period, two groups of riding horses were used: Group A consisting of 58 horses used for student equitation courses (32 with training prior to admission and 26 without) and Group B consisting of 26 horses owned by two riding schools (school-I and school-II). To assess fitness, all horses performed a standardised exercise test (SET) at the start (SET-I) and end of the training period (SET-II) measuring heart rate (HR bpm) and speed (m/s). In addition, all horses were monitored daily during the training period for their health and workload.In Group A, trained horses had significantly lower HRs in SET-I (P = 0.05) compared to untrained horses and in SET-II, trained horses tended to have lower HRs than untrained horses, though this was not statistically significant (P = 0.057). During the training period all horses received an identical workload. A total of 19.0% of Group A horses ended the training period prematurely for veterinary reasons (PTEV); of those untrained horses had earlier a PTEV in the training period (after 2.8 ± 1.3 weeks) than trained horses (after 4.1 ± 1.5 weeks, P = 0.030).In Group B, school-I and school-II horses did not differ significantly in fitness level nor in workload. More school-II horses ended the training period prematurely for veterinary reasons (n = 7; 70%) compared to school-I horses (n = 4; 25%, P = 0.032), although seven (63.6%) of these horses were still continuously used in riding lessons. In both groups (A and B), small injuries (without a temporary training break) were significantly associated with premature training ends for veterinary reasons later on: in Group A small injuries preceded 27.3% of the PTEVs (P = 0.005) and in Group B small injuries preceded 54.5% of the PTEVs (P = 0.030).In conclusion, as all horses in each subgroup had the same workload, the occurrence of PTEV seemed not associated with the workload. In Group A horses, level of fitness seems to be an important factor for the point in time injuries will occur during the training period. In all horses, injuries were more likely when a temporary training break was not taken following seemingly minor injuries. Since a lot of injured Group B horses were used in riding lessons against veterinary advice, this may indicate that riding school owners have different perception on welfare and if true this may cause serious welfare problems.     

Risk factors for musculoskeletal injuries of the lower limbs in Thoroughbred racehorses in New Zealand

AIM: To investigate risk factors for injury to musculoskeletal structures of the lower fore- and hind-limbs of Thoroughbred horses training and racing in New Zealand. METHODS: A case-control study analysed by logistic regression was used to compare explanatory variables for musculoskeletal injuries (MSI) in racehorses. The first dataset, termed the Training dataset, involved 459 first-occurrence cases of lower-limb MSI in horses in training, and the second, the Starting dataset, comprised a subset of those horses that had started in at least one trial or race in the training preparation that ended with MSI (n=294). All training preparations for horses that did not suffer from MSI for which complete data were available were used in the analyses as controls, and provided 2,181 and 1,639 preparations for the Training and Starting datasets, respectively. Multivariate logistic regression was used to evaluate risk factors, and results were reported as odds ratios (OR) and 95% confidence intervals (CI). RESULTS: Horses aged > or =5 years were at higher risk of injury than 2-year-olds. Elevated odds of MSI occurred in horses in the Starting dataset that were training in the 1997-1998 year compared with the 1999-2000 year, and in those horses where trials comprised >20% of all starts in a preparation. Training preparations that ended in winter, and horses in their third or later training preparation, had lower odds of MSI compared with those ending in other seasons or the first preparation, respectively. Reduced odds of MSI were observed in preparations in which starts occurred compared with those that had no starts, and in the Starting dataset, preparations that included more than one start had a reduced likelihood of MSI compared with preparations that had only one start. In the Training dataset, preparations longer than 20 weeks were associated with reduced odds of MSI compared with those shorter than 20 weeks. Cumulative racing distance in the last 30 days of a training preparation was best modelled with linear and quadratic terms. Results indicated that increasing cumulative racing distances were associated with an initial reduction in the odds of MSI that then levelled out and finally appeared to increase again as the explanatory variable continued to increase. The risk of MSI varied significantly between trainers. CONCLUSION: This study identified intrinsic (age) and extrinsic risk factors for MSI in training and racing Thoroughbreds in New Zealand. The risk of MSI initially decreased, then increased, as cumulative racing distance increased. Significant variation between trainers indicated management and training methods influence the risk of MSI.     

Prevalence of superficial digital flexor tendonitis and suspensory desmitis in Japanese Thoroughbred flat racehorses in 1999

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.     

The effect of collection and extension on tarsal flexion and fetlock extension at trot

A recent epidemiological study indicated that various factors may be related to injury in dressage horses, but the mechanism by which these injuries occur has yet to be determined. The suspensory ligament (SL) is a frequent site of injury, and it is assumed that greatest strain is placed on this structure in collected trot; this has yet to be proved conclusively. The study aimed to investigate the effect of collected and extended trot on the hindlimb movement pattern. Four dressage horses were fitted with markers and inertial motion sensors (IMS). High‐speed video was obtained for 2 strides on each rein in collected and extended trot on 3 different surfaces: waxed outdoor; sand/plastic granules; and waxed indoor. Maximal tarsal flexion during stance and distal metatarsal coronary band ratio (MTCR), representing fetlock extension, were determined. Inertial motion sensor data determined stride duration, speed and stride length. Data were compared between collection and extension within horses on each surface, and compared between surfaces. Collected trot had significantly lower speed and stride length but longer stride duration than extended trot on all surfaces. All horses had less tarsal flexion and fetlock extension in collected compared with extended trot (P<0.05), which is likely to increase SL loading. The study findings indicate that extended trot may increase SL strain, providing a possible explanation for the high incidence of SL injury in horses trained for extravagant movement. It is possible that substantial use of extended trot could be a risk factor for development of suspensory desmitis, which might be one contributory factor in the prevalence of suspensory desmitis in young horses repeatedly undertaking extravagant movement.     

Arthroscopic diagnosis and treatment of intra-articular insertional injuries of the suspensory ligament branches in 18 horses

REASONS FOR PERFORMING STUDY: Clinical association between the branches of insertion of the suspensory ligament (SL) and metacarpophalangeal (MCP) and metatarsophalangeal (MTP) joints has been reported. However, there has been no assessment of the lengths of the SL branches which are subsynovial with respect to the joints or reports of involvement of the MCP/MTP joints in injuries of the SL branches. OBJECTIVES: To establish proportions of SL branches subsynovial with respect to the MCP/MTP joints and report clinical and arthroscopic findings in horses with desmitis of SL branches identified as having an articular component to the lesion. HYPOTHESIS: Arthroscopic surgery enables identification and potential treatment of intra-articular injuries of SL branches. METHODS: Twelve forelimbs and 13 hindlimbs were dissected and the total and subsynovial lengths of the SL branches recorded. Case records of horses with intra-articular injuries of the SL branches were reviewed and 18 animals identified. Diagnostic information and arthroscopic findings were recorded and results of treatment determined by telephone follow-up. RESULTS: Of SL branches, 28.45% in the forelimb and 29.56% in the hindlimb were subsynovial to the MCP and MTP joints. All animals with intra-articular lesions of the SL branch were lame and had distension of the affected MCP/MTP joint. In 16 horses (17/22 branches), there was palpable thickening of the affected SL branch. Disrupted infrastructure was evident ultrasonographically in 15/17 branches and involvement of the dorsal articular surface of the ligament was predicted in 12/17 branches. Following arthroscopic intervention, 13 horses returned to work at a level equal to or greater than that achieved prior to injury and 2 returned to work at a lower level. Three horses incurred separate injuries and were retired or subjected to euthanasia. CONCLUSIONS: Articular involvement should be considered in animals with injuries of an SL branch and concurrent distension of the MCP/MTP joint. Arthroscopy is necessary to identify such lesions confidently and to direct case management. POTENTIAL RELEVANCE: Arthroscopy of the MCP/MTP joints can make a positive contribution to the assessment and management of some SL branch injuries.     

Physical Parameters and Risk Factors Associated with the Elimination of Arabian and Crossed Arabian Endurance Horses during a 120-km Endurance Race

Endurance racing is one long-distance event among the equine sporting activities associated with severe injuries and metabolic derangements that impede the health status of horses participating in the event. Therefore, this study evaluated the physical parameters and risk factors associated with the elimination of Arabian and crossed Arabian endurance horses during a 120-km race. Fifty-three Arabian and crossed Arabian endurance horses aged 6 to 15 years old participated in an endurance race of 120 km. All the horses were examined and found fit according to Fédération Équestre Internationale (FEI) regulations. After the endurance race 14 Arabian endurance horses completed the race successfully while 31 Arabian and crossed Arabian were eliminated. Their speed and heart rates were significantly higher (P < .0001). There were significant differences in skin recoil (P < .0395), color of mucous membrane (P < .0189), intestinal motility (P < .0124), and capillary refill time (P < .0082). There also were significant differences in age (P < .0018), breed (P < .0119), and equine establishments (P < .0205) among the eliminated horses and the Arabian and crossed Arabian endurance horses that successfully completed the race. In conclusion, the physical parameters and risk factors were significantly associated with the elimination of Arabian and crossed Arabian endurance horses. Therefore, close monitoring of the physical parameters and risk factors are essential in order to improve the performance of Arabian and crossed Arabian horses, and further studies are required on other associated parameters.     

Parameters influencing prevalence and outcome of tendonitis in Thoroughbred and Arabian racehorses

Flexor tendonitis and suspensory desmitis are among most prevalent musculoskeletal injuries observed in racehorses. The aim of this study was to determine which horse and race-related parameters can help to diminish the possibility of injury or--when injury has occurred--to evaluate the potential for the horse to continue a successful career after convalescence. Special attention was given to the comparison of Arabian and Thoroughbred racehorses. 187 horses with ultrasonographically visible lesions were included in the study. Following parameters were analyzed: structure (Superficial Digital Flexor Tendon [SDFT], Deep Digital Flexor Tendon [DDFT], Suspensory Ligament [SL]); percentage of cross sectional area increase; hypoechogenic lesion character; in horses with SDF tendonitis - tendonitis grade according to Genovese. This study showed that Thoroughbreds are more at risk of musculoskeletal problems than Arabian racehorses. In both breeds, the most frequent injuries concern SDFT, then SL. Over 95% of tendonitis concern forelimbs. In Thoroughbreds, the prevalence of tendonitis is higher in bigger horses, in males when compared to females and in fence/steeple racehorses when compared to flat track racehorses. The inside limb is more at risk of SDF tendonitis, when the external limb - of SL desmitis. Tendonitis severity increases with age and is greater in steeplechasers when compared to flat track racehorses. The outcome of tendonitis without hypoechogenic lesion is much better than that with hypoechogenic lesion. Evaluation of hypoechogenic lesion length is an easy and accurate prognosis tool, as the chances of returning to racing drop dramatically with lesions longer than 12 cm.     

Lipid Utilization Pathways Induced by Early Training in Standardbred Trotters and Thoroughbreds

Controversial results on lipid utilization as an energy source during training in horses are found in the literature. The objective of this study was to assess blood lipid profile during different training programs in horses. Seventeen Standardbred horses (400 ± 50 kg) and 17 Thoroughbred horses (380 ± 15 kg) followed different training programs. Blood lipid profile, including triglycerides (TGs), total cholesterol, high-density lipoprotein (HDL), and low-density lipoprotein (LDL), was analyzed, and very-low-density lipoprotein (VLDL) concentration was calculated. Data were analyzed using Student t test, and linear regressions were done. Cholesterol and LDL decreased during training programs in Standardbred trotters (P = .0001 and P = .0053, respectively), and VLDL was found to be close to the significance level (P = .053). Blood lipid profile, including TGs (P = .0014), cholesterol (P = .0057), HDL (P = .0128), LDL (P = .0091), and VLDL (P = .0014), varied throughout the training program in Thoroughbred horses. Negative slope of blood lipids and positive slope of TG linear regression in Standardbred trotters were significant for all parameters (P ≤ .05), whereas cholesterol and LDL regression showed poor P and r² values and HDL P value was slightly above the significance level (P = .069) in Thoroughbred horses. TGs and VLDL showed a positive linear trend in Thoroughbred horses (P = .002). Exercise and different training programs lead to significant variations of lipid profile and lipid utilization in horses. Lipid utilization as an energy source improved with training in Standardbred trotters, whereas this was not the case in Thoroughbred horses. Further studies on the effect of training programs using different conditions and horse breeds would be necessary to understand lipid utilization as an energy source in athletic horses.     

Competition Horses Housed in Single Stalls (II): Effects of Free Exercise on the Behavior in the Stable, the Behavior during Training, and the Degree of Stress

Although housing horses in single stalls limits their natural behavior to a great extent, this housing system is widespread in Germany, especially for competition horses. To improve the welfare of this system, free exercise on pastures or paddocks is deemed suitable, but it is also feared because of injuries and decreased willingness or motivation to perform. In the present study, three treatments were investigated with regard to their effect on the behavior of six competition horses in the stable, behavior during training, and on their degree of stress: daily training without free exercise (no turnout [NT]), solitary turnout for 2 hours after training, and 2-hour turnout in groups of two after training (group turnout). The horses’ behavior in the stable was continuously analyzed through video recordings (2 pm to 6 am) on 3 days at the end of each treatment. The degree of stress was evaluated daily by heart rate variability at rest. The behavior during training was evaluated by a questionnaire answered by the riders, and the distance covered during training was measured by global positioning system. When NT was allowed, the horses showed less lying in the stable compared with the treatments with turnout. Heart rate variability measurements resulted in great individual differences, but generally, there was a higher degree of stress shown with the treatment NT according to the following parameters: standard deviation of inter-beat-intervals (SDNN), square root of the mean of the sum of the squares of differences between successive inter-beat-intervals (RMSSD), and ratio between low frequency and high frequency (LF/HF). The willingness to perform was evaluated as being slightly better in the treatments with turnout than in the treatment without turnout.     

Investigating duration of nocturnal ingestive and sleep behaviors of horses bedded on straw versus shavings

Horses are stabled overnight for a number of practical reasons; however, there is little research quantifying nocturnal equine behavioral patterns or the extent to which different environments influence nocturnal behavior. The aim of this study was to establish whether differences in duration of sleep and ingestive behaviors were apparent for horses bedded on straw (group 1) or shavings (group 2). Ten geldings of mixed breed (mean age: 7.3 ± 3.53 years) bedded on either shavings (n = 5) or straw (n = 5) were observed between 7 pm and 7 am. Duration of behaviors according to a predefined ethogram was recorded in minutes using a video recorder and continuous focal sampling. Mann–Whitney U tests were used to identify whether any significant differences in duration of ingestion and sleep behaviors occurred for horses bedded on straw compared with shavings. Of the total observation period, group 1 spent, on average, 29.3% of their time budget engaged in recumbent behaviors, compared with 12.2% for group 2. However, no significant differences in duration were established between horses bedded on straw or shavings for standing sleep, sternal recumbency, and lateral recumbency behaviors (P > 0.05). Ingestive behaviors occupied approximately one-third of the time budget, with no significant difference (P > 0.05) observed between groups. On average, group 1 spent a longer proportion of the observation period ingesting bedding (8.1%) compared with group 2 (1%). Duration of bedding ingestion appeared to peak between 1 am and 7 am for both groups. Although not quantified, general observations revealed horses were motivated to alternate between eating hay and bedding in both groups, owing to the prevalence of bedding ingestion. The results indicate that straw bedding facilitates the display of ingestive and sleep behaviors, whereas horses bedded on shavings spent a greater proportion of their nocturnal time budget engaged in “other” behaviors. Further research is required to investigate the extent to which different types of bedding material enrich the environment of horses that are stabled overnight.     

Questionnaire on the process of recovering horses from general anesthesia and associated personnel injury in equine practice

ObjectiveTo collect data about the current practice of recovering horses from general anesthesia and recovery personnel safety.Study designOnline survey.MethodsAn online questionnaire, including questions on general demographic data, recovery drugs, modality and characteristics of equine recovery and morbidity and mortality, was designed and distributed via e-mail to equine practitioners worldwide.ResultsPractitioners from 22 countries completed 373 questionnaires; 53% of the participants were board-certified equine surgeons, and the remainder were board-certified anesthesiologists (18%), large animal residents (8%), general practitioners (7%), large animal interns (6%), anesthesia residents (4.5%) and veterinary technicians (1.6%). Respondents were employed by academia (58%) or private practice (42%). Of the respondents employed at a university, 93% had a board-certified anesthesiologist on staff compared with 7% of respondents employed at a private practice. Most of the respondents assist horses during recovery, with 23% assisting every recovery and 44% assisting recovery in the majority of cases. Reasons for choosing to assist horses during recovery were: orthopedic procedures (57%), neurological deficits (49%), bad health (47%), history of poor recovery (44%), foals (42%), draft breeds (30%), magnetic resonance imaging (17%) and computed tomography (16%). Unacceptable recoveries were reported by 77% of participants. Commonly reported complications during recovery with any method were: orthopedic injury (66%), myopathy (54%), skin abrasion (53%) and airway obstruction (37%). The incidences of unacceptable quality of recovery (p = 0.09) or personnel injury (p = 0.56) were not different between assisted and nonassisted recoveries; however, more equine fatalities were reported for assisted recoveries (p < 0.006). Practitioners in academia reported more unacceptable recoveries (p < 0.0007) and personnel injuries (p < 0.002) compared with those in private practice.ConclusionsThe method of recovery differs among hospitals. Recovery personnel injuries associated with assisting horses during recovery are an important and previously unreported finding.     

Musculoskeletal injuries in Standardbred racehorses on Prince Edward Island

A study of musculoskeletal injuries in Standardbred racehorses on Prince Edward Island was conducted to determine the incidence and risk factors for injury. Monthly information was collected from 10 trainers and 153 Standardbred horses over a 12-month period. Seventeen new injuries were identified in pacers, representing a horse level incidence risk of 23% and an incidence rate of injury of 2.19 per horse-month at risk. Forty-one percent of the injuries occurred during a race, 53% during training and 6% during jogging. Fourteen horses had experienced a previous injury and 3 of these horses experienced a new injury during the study period. Potential risk factors for injury were the speed at which the horse was trained, previous injury, and the conformational fault of offset knees.     

Conflict Behavior in Show Jumping Horses: A Field Study

The study objective was to determine if there was a relationship between behavioral and physiological stress measures in sport horses and their performance. Nineteen horses competed in show jumping events (6 housed at the center and 13 transported), while 5 horses at home training served as controls. The competition horses were assigned to “light” (obstacles ≤100 cm) and “difficult” class (obstacles >100 cm). The conflict behaviors (CBs/min) in two rounds were calculated. Total faults were classified as “less faults” (≤one fault) or “more faults” (>one fault). Salivary cortisol concentration (SCC) before the first round (SCC-SP1), 20 minutes (SCC-SP2), and 60 minutes after the second round (SCC-SP3) was measured. The increase (SCC-in) and decrease (SCC-dec) in SCC were calculated. No effect of competition was found. Horses that waited longer for the second round had greater CB (P < .05). Conflict behavior was more frequent in horses from the “more faults” (P = .05) and “difficult” (a tendency; P = .06) classes. No correlation of CB with SCC was found. SCC-SP2 was greater in “more faults” (P < .01) and “transported” (P < .01) horses. Competition increased the SCC (P < .05), whereas SCC-SP2 was greater in less successful horses (P < .05). Transported horses and horses with more faults had the greatest SCC-SP2 and SCC-dec (P < .05). Our results suggest that horses which presented stress response were also less successful in competition. The adoption of effective methods to reduce transport and competition stress could enhance welfare and performance of sport horses during competition.     

Descriptive epidemiology of fractures occurring in British Thoroughbred racehorses in training

REASONS FOR PERFORMING STUDY: Musculoskeletal injury is the major cause of days lost from training and wastage in Thoroughbred racehorses. Little scientific information is available on the majority of injuries occurring in training. OBJECTIVES: To estimate the incidence of fractures in British racehorses in training and describe the occurrence of different fracture types and bones involved. METHODS: Thirteen UK racehorse trainers participated in a prospective study, providing data on horses in their care for 2 years. Details on horses, their daily exercise and fracture occurrence were recorded. RESULTS: A total of 1178 horses provided 12,893 months at risk. Nontraumatic fracture incidence was 1.15/100 horse months (95% CI = 0.98, 1.35) and 78% of fractures occurred during training. A wide variety of fracture types and bones were involved, although at least 57% were stress fractures. Pelvic and tibial stress injuries accounted for 28% of fractures diagnosed. CONCLUSIONS: It is important to study injuries in training as well as in racing. The number of stress fractures suggests that training regimes for young Thoroughbreds could often be improved to create a more robust skeleton, able to withstand injury. POTENTIAL RELEVANCE: Studying injuries in racehorses in training can provide a scientific basis for the design of safer training regimes.     

Descriptive epidemiology of fracture,tendon and suspensory ligament injuries in National Hunt racehorses in training

Reasons for performing study: While fractures and tendon injuries are known to be important diseases in National Hunt (NH) racehorses during racing, there are no accurate estimates of their incidence in NH training yards. Objectives: To estimate the incidence of fractures and tendon and suspensory ligament injuries (TLIs) in NH racehorses in training; to describe the injuries incurred and to compare injury incidence rates by horse age, trainer, gender and background (ex‐flat vs. ex‐store horses). Methods: Cohort data were collected from 14 UK NH training yards for 2 racing seasons. Daily exercise regimens and details of fractures and TLIs occurring in study horses were recorded. Results: Data were gathered from 1223 horses that spent 9466 months at risk of injury. The fracture incidence rate was 1.1/100 horse months and varied significantly by trainer (P<0.001) but not by gender, age or background. The pelvis and third metacarpal bone (MCIII) were the most common fracture sites, although this varied between racing and training. The TLI incidence rate was 1.9/100 horse months and varied significantly by trainer (P = 0.05) and age (P<0.001) but not by gender or background. However, exstore horses were significantly more likely to have a TLI on the racecourse than ex‐flat horses (P = 0.01). Superficial digital flexor injuries accounted for 89% of all TLIs, the remainder being suspensory ligament injuries. Conclusions and potential relevance: Fractures and TLIs are important causes of morbidity and mortality in NH racehorses in training in England. This study provides accurate estimates of their incidence in this population and provides a baseline against which to monitor the effect of future interventions.     

Reduced high intensity training distance had no effect on VLa4 but attenuated heart rate response in 2-3-year-old Standardbred horses

Background

Training of Standardbred race horses aims to improve cardiovascular and metabolic functions but studies on the effects of different training strategies from breaking till racing are lacking. Sixteen horses with the goal to race as 3-year-olds were studied from breaking (1-year-olds) to December as 3-year-olds. Horses were allocated to either a control (C) or reduced (R) training program from 2 years of age. The aim was to evaluate the effect of reducing the distance of high intensity exercise by 30% with respect to velocity at lactate concentration 4 mmol/l (V_La4), blood lactate and cardiovascular response. All training sessions were documented and heart rate (HR) was recorded. A standardized exercise test of 1,600 m was performed 10 times and a V_La4 test was performed five times.

Results

C horses initially exercised for a longer time with a HR >180 beats per minute compared to R horses (P < 0.05) but after 6–9 months, time with HR >180 bpm decreased in C and were similar in the two groups (P > 0.05). Over the 2-year period, recovery HR after the 1,600 m-test decreased in both groups but was within 2 months lower in C than in R (P < 0.05). C horses also had lower resting HR as 3-year-olds (P < 0.01) than R horses. In C, post exercise hematocrit was higher than in R (P < 0.05). There was a tendency (P < 0.1) towards a larger aortic diameter in C as 3-year-olds (C: 1.75 ± 0.05, R: 1.70 ± 0.05 cm/100 kg BW). Left ventricle diameter and blood volume (in December as 2-year-olds) did not differ between groups. There were no differences between groups in post exercise blood lactate concentration or in V_La4. Both groups were equally successful in reaching the goal of participation in races.

Conclusions

Horses subjected to a reduced distance of high intensity training from the age of 2 showed an attenuated heart rate response, but were able to maintain the same V_La4 and race participation as horses subjected to longer training distances.     

Prevalence of osteochondrosis in the limb joints of South German Coldblood horses

This study aimed to quantify the factors associated with the prevalence of the radiological signs of osteochondrosis (OC) and osteochondrosis dissecans (OCD) in South German Coldblood (SGC) horses. The prevalence of OC and OCD in fetlock and hock joints was analysed in 167 young coldblood horses with a mean age of 14 months. The presence of at least one osteochondrotic lesion (OC) in fetlock or hock joints was documented for 61.7% of the horses and 26.9% of the horses had osseus fragments. Osteochondrotic findings at the dorsal aspect of the sagittal ridge of the third metacarpal/metatarsal bone were seen in 53.9% of the horses and palmar/plantar osseous fragments in fetlock joints in 16.2% of the horses. Hock joint OC was found in 40.1% of the horses and hock OCD in 0.6%. Osteochondrotic findings in the distal part of the tibia were prevalent in 28.1% and in the lateral trochlea tali in 17.4% of the horses. The sex of the investigated horses significantly influenced the prevalence of OC in fetlock and hock joints, as well as the findings in the distal part of the tibia and lateral trochlea tali. Age at radiological examination was significant for the prevalence of OC in hock joints, palmar/plantar osseous fragments in fetlock joints and osteochondrotic findings in the distal part of the tibia. Female horses showed a 2-fold higher risk for OC in fetlock and hock joints than male horses. The distribution of the affected horses by age classes showed that radiographic signs of OC in fetlock and hock joints significantly increased at an age of about 1 year. We can conclude from our study that fetlock and hock OC is a prevalent radiographic finding in more than 1-year-old female and male SGC horses.     

The Influence of Stable Management and Feeding Practices on the Abnormal Behaviors Among Stabled Horses in Malaysia

The present study aimed to provide preliminary data on the prevalence of oral stereotypic, locomotory stereotypic, and redirected behaviors as well as their associations with stable management and feeding practices. In this cross-sectional study, a total of 207 working horses used for leisure riding, equestrian sport, polo, endurance, and patrolling were selected from seven equine facilities. Data on the stable management and feeding practices were obtained through the stable records, interviews, and on-site monitoring visits, whereas the prevalence of abnormal behaviors in the studied population was determined using the instantaneous scan sampling method. Most horses in the present study worked for more than 8 hours per week (n = 93). In addition, more horses were fed three times per day (n = 65) with different amounts of hay, concentrate, and chaff. Among the study population, oral stereotypic behaviors had the highest prevalence (n = 281; 54%), followed by redirected behavior (n = 181; 34%), and locomotory stereotypic behaviors had the lowest prevalence (n = 63; 12%). The oral stereotypic behavior was found to be significantly influenced (P < .05) by the working hours, amount of hay, and amount of concentrate. Both locomotory stereotypic and redirected behaviors were found to be influenced (P < .05) by the number of feedings per day and the amount of hay. In summary, the present study has proven that the stable management and feeding practices could influence the prevalence of different abnormal behaviors in the majority of working horses, with oral stereotypy being the most common abnormal behavior in this country.     

Prevalence of Electrolyte Disturbances and Perianesthetic Death Risk Factors in 120 Horses Undergoing Colic Surgery

The objective of this study was to determine the prevalence of intraoperative electrolyte disturbances and risk factors associated with perianesthetic death in horses undergoing colic surgery. The files of 120 horses meeting the inclusion criteria were reviewed. Data retrieved from the medical records, including demographic data and the occurrence of electrolyte disturbances and other intraoperative complications, were analyzed with a two step-approach by univariate and multivariate logistic regression models. Hypocalcemia was the most represented electrolyte disturbance (52.5%), followed by hypokalemia (30.0%) that was associated with intraoperative administration of salbutamol (P = .045). Perianesthetic death occurred in 46 horses, accounting for an overall mortality rate of 38.3%. Risk factors associated with death were anesthetic duration (P = .001), body weight (P = .020), presence of gastric reflux before anesthesia (P = .021), and intraoperative tachycardia (P = .043) and acidosis (P = .025). The mortality in the study population was comparable to previously reported findings. Based on the study findings, it is advisable to optimize hemodynamics prior to anesthesia, in order to prevent intraoperative tachycardia that is associated with increased risk of death. Heavier horses and those with gastric reflux may have a higher risk of fatalities, and intraoperative salbutamol administration may contribute to hypokalemia.     

Effects of short-term light to heavy exercise on gastric ulcer development in horses and efficacy of omeprazole paste in preventing gastric ulceration

OBJECTIVE: To determine the effects of 8 days of light to heavy exercise on gastric ulcer development in horses and determine the efficacy of omeprazole paste in preventing gastric ulceration. DESIGN: Randomized, controlled, multicenter clinical trial. ANIMALS: 102 horses with normal-appearing gastric mucosa on endoscopic examination that were in light to heavy training. PROCEDURES: Horses at 4 trial locations were allocated into replicates and sham dosed orally (empty syringe) or treated with a paste formulation of omeprazole (1 mg/kg [0.45 mg/ lb], PO) once daily for 8 days. Training regimens varied among locations and included early training for western performance events; walking, trotting, and cantering in a mechanical exerciser; and race training (2 locations). Prevalences of gastric ulceration at the completion of the 8-day treatment period were compared between groups. RESULTS: At the end of the 8-day treatment period, the proportion of omeprazole-treated horses free from gastric ulceration (88%) was significantly higher than the proportion of sham-dosed horses free from gastric ulceration (27%). CONCLUSIONS AND CLINICAL RELEVANCE: Results showed that horses in light to heavy training for as short as 8 days were at risk of developing gastric ulcers and that administration of omeprazole paste decreased the incidence of gastric ulcers.