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Keywords:

  • horse;
  • lameness;
  • metabolic;
  • long distance;
  • race

Summary

  1. Top of page
  2. Summary
  3. Introduction
  4. Materials and methods
  5. Results
  6. Discussion
  7. Acknowledgements
  8. Conflicts of interest
  9. Manufacturer's address
  10. References

Reasons for performing study: Endurance is the fastest growing Féderation Équestre International (FEI) discipline and the large number of eliminations on veterinary grounds needs to be investigated.

Objectives: To document elimination rates and explore potential risk factors for elimination due to lameness or metabolic reasons in 9 countries representing 5 continents.

Methods: Data for rides of ≥100 km (‘elite endurance rides’) in Australia, France, Italy, South Africa, Spain, United Arab Emirates (UAE), UK, Uruguay and USA were collected from the FEI website. Data were collected for all started horses on the country, number of horses in the class, ride distance, class (e.g. young rider class) and the average speed of the winning horse. Retirements, eliminations for lameness, metabolic and other reasons were recorded. Uni- and multivariable logistic regression models were used to assess the effect of country, number of horses in the class, ride distance and young rider class on 2 outcomes (elimination for lameness and metabolic reasons).

Results: Data for 157 classes at 91 events were analysed. The UAE had the highest number of entries (1497), followed by France (1029) and Spain (408). Of 4326 started horses, 46.0% finished the ride. Lameness was the most common cause of elimination in all countries followed by metabolic reasons (69.2 and 23.5% of all eliminations, and 31.8 and 10.8% of all started horses, respectively). Eight percent of horses were retired by the rider, having passed the veterinary examination. In multivariable analysis, the risk of elimination for lameness was associated with the country in which the ride was held, and the risk significantly increased (OR = 1.60) for horses competing in rides with ≥80 entries. The risk of elimination for metabolic reasons was also significantly associated with the country in which the ride was held and the risk significantly increased (OR = 2.17) for horses competing in rides with ≥100 entries in the multivariable analysis.

Conclusions and potential relevance: Elimination rates vary between countries, with lameness being the most common reason for elimination globally. Analysis of retrospective data showed country and number of started horses to be risk factors for elimination due to lameness and for elimination due to metabolic disorders. A prospective study is needed to assess the effects of environmental conditions, individual horse speed and other variables on the risk of specific causes of elimination.


Introduction

  1. Top of page
  2. Summary
  3. Introduction
  4. Materials and methods
  5. Results
  6. Discussion
  7. Acknowledgements
  8. Conflicts of interest
  9. Manufacturer's address
  10. References

Endurance is the fastest growing Féderation Équestre International (FEI) discipline. Data obtained from the FEI (http://www.fei.org) showed that between 1994 and 2008, the number of FEI endurance classes increased from 16 to 488. In 2008, 188 international FEI endurance events were held worldwide (one event can have several classes), with 97% (182/188) of events running at least one class of ≥100 km distance. Classes have specific criteria, such as distance and whether only young riders (aged ≤21 years) are allowed to participate.

The high elimination rate from endurance rides has been a regular matter for discussion in professional and public forums. Moreover, in recent years, elimination rates seem to have increased (Marlin et al. 2008), which emphasises the need for scientific research in the equine endurance discipline.

Several epidemiological studies have been published investigating risk factors for wastage and/or injuries in Thoroughbred racehorses (Rossdale et al. 1985, Parkin et al. 2004a,b, Verheyen and Wood 2004), event horses (Singer et al. 2003; Murray et al. 2006; Singer et al. 2008) and dressage horses (Murray et al. 2010). Anecdotal information suggests that elimination rates at endurance rides vary between countries and eliminations occur more frequently at higher speeds; however, to date, no large scale evidence-based data are available to support these hypotheses. Marlin et al. (2008) investigated the rates of eliminations and the number of horses requiring treatment in 8 global regions between 2005 and 2007, including 4 endurance rides each year in each region. The number of eliminations for lameness increased, but the number of eliminations due to metabolic reasons remained unchanged in the period assessed. Flamino and Rush (1998) reported that horses performing strenuous exercise at endurance rides suffered more from metabolic disorders in hot and humid conditions than in colder environments. To our knowledge, to date no large-scale epidemiological studies on endurance horses have been published, and risk factors for eliminations from endurance rides have not been assessed. It is anticipated and suggested by personal experience, that difficult terrain (slippery, too hard, too soft), or sudden changes of terrain can lead to high elimination rates for lameness, especially if the speed is also fast. The aims of this study were to document elimination rates and explore potential risk factors for elimination due to lameness or metabolic reasons in 9 countries representing all 5 continents. Weather conditions and terrain vary considerably between countries; therefore, we hypothesised that the country would have a significant effect on elimination rates for both lameness and metabolic reasons.

Materials and methods

  1. Top of page
  2. Summary
  3. Introduction
  4. Materials and methods
  5. Results
  6. Discussion
  7. Acknowledgements
  8. Conflicts of interest
  9. Manufacturer's address
  10. References

Data collection

Data for 4326 started horses in endurance rides of ≥100 km held in 2008 in Australia, France, Italy, South Africa, Spain, United Arab Emirates (UAE), UK, Uruguay and USA were collected from the FEI website (http://www.fei.org). Countries were selected based on the anecdotally high number of endurance rides/riders and/or their tradition in endurance riding, and to represent 5 continents. An ongoing study using the FEI database (http://www.fei.org) (A. Nagy et al. unpublished data) revealed that in 2008 there were 7017 starters at FEI rides of ≥100 km distance. The 4326 started horses included in the current study represents 61.7% of all starters from all countries.

For each class, the country, the distance, whether the class was restricted to young riders, the number of started horses and the winning speed were recorded. Horses that were retired or eliminated for lameness, metabolic or other reasons were recorded. At FEI endurance rides horses are examined by veterinarians before and throughout the competition and are eliminated if their metabolic status or orthopaedic condition are not considered to be adequate to enable them to continue the ride (‘fit to continue’). Endurance is unique in that horses can be eliminated for the above reasons before, during the ride, and also at the final veterinary examination after completing the ride. Elimination is a result of anonymous voting by 3 veterinarians, unless the person responsible for the horse acknowledges the reason for elimination and requires no voting. Horses are eliminated for lameness, by definition, if they have ‘consistently irregular gait’ (FEI rules 2008). Horses are eliminated for metabolic reasons if the voting veterinarians consider that the horse's metabolic status is compromised (based on general impression, heart rate, cardiac recovery index [Ridgway 1994], colour and moisture of mucous membranes, capillary refill time, the time it takes for a pinched skin fold over the point of the shoulder to flatten [skin tent] and presence and intensity of gut sounds) and that the horse's health would be at risk if it continued the ride. Elimination for metabolic reasons can also occur due to a heart rate higher than defined in the ride schedule (usually >64 beats/min) at specified veterinary inspections (the second inspection in all but the final veterinary inspection or at the first [and only] inspection in the final veterinary inspection). Horses failing the first veterinary inspection at a vet-gate because of a heart rate higher than defined can be represented within the time specified in the ride schedule (usually 20 min) and are not eliminated if judged to be ‘fit to continue’ when re-presented. In the final veterinary inspection no re-presentation is permitted. In the study presented here, all disqualifications and eliminations for reasons other than lameness or metabolic (e.g., sore back) were classified as ‘other eliminations’. By definition of the FEI rules, horses can only be retired from the competition if they pass the veterinary inspection, otherwise they are eliminated. The variables and categories assessed are summarised in Table 1.

Table 1. Variables assessed as potential risk factors for 2 outcomes: elimination for lameness and elimination for metabolic reasons from Féderation Équestre International endurance rides of ≥100 km distance in 9 countries in 2008
VariableResponses
  1. UAE = United Arab Emirates.

CountryAustralia, France, Italy, South Africa, Spain, UAE, UK, Uruguay, USA
Number of entriesNumber of entries in the class
Young rider (≤21 years)Yes or no
DistanceRide distance (km)

Statistical analysis

Cases were defined as horses that were eliminated for lameness or metabolic reasons and separate analyses were performed for the 2 outcomes. Univariable logistic regression was performed to identify associations between potential risk factors (country, distance, number of entries, young rider) and the 2 outcomes (elimination for lameness and metabolic reasons). The ride distance and number of entries in the class were considered as continuous and categorical variables in the analysis and the fit of the variables in the model were compared by assessing the change of deviance (assuming the change in deviance follows a Chi-squared distribution with n degrees of freedom, where n is the number of extra parameters fitted). Variables that had P values <0.2 in the univariable analysis were considered for inclusion in a multivariable model. Variables were retained in the model if they significantly reduced the residual deviance of the model (likelihood ratio statistic, P<0.05). Two multivariable models were created for the 2 outcomes under investigation. Statistical analysis was performed using a dedicated statistical software package (Egret)1 and statistical significance was set at P<0.05.

Results

  1. Top of page
  2. Summary
  3. Introduction
  4. Materials and methods
  5. Results
  6. Discussion
  7. Acknowledgements
  8. Conflicts of interest
  9. Manufacturer's address
  10. References

Ride data

Data were collected from 158 classes held at 97 events in the 9 countries included in the study (Table 2). The number of classes of different distances varied between countries. In most countries classes of 100–120 km predominated; in only Australia and the USA were there more classes of >120 km than 100–120 km. The greatest number of entries was recorded in the UAE (1497 in total), followed by France (1029) and Spain (408). The number of entries per class ranged from 1–140 and the mean number of entries per class was highest in the UAE (71.3), followed by Spain (40.8) and France (38.1). In Italy the mean number of entries per class was 29.1; in the other countries the mean number of entries per class was much lower, ranging from 10.3 (Australia) to 16.2 (South Africa). There were 35 young rider classes altogether, including both the 100–120 km and >120 km distance categories. The highest winning speeds for both 100–120 and 160 km distances were recorded in the UAE (26.2 km/h and 24.7 km/h, respectively).

Table 2. Number of events, classes of different distances, total number of entries and mean and maximum winning speed for different distance classes in Féderation Équestre International endurance rides of ≥100 km in 9 countries in 2008
CountryEvents (n)Classes (n)Total number of entries (n)Mean winning speed ± s.d. (km/h)Maximum winning speed (km/h)
Total100–120 km>120 km100–120 km>120 km100–120 km>120km
Australia81551015517.5 ± 4.415.4 ± 2.624.119.4
France2227189102917.5 ± 1.717.4 ± 1.621.018.8
Italy6108229116.8 ± 1.715.6 ± 0.518.716.0
South Africa5159624317.3 ± 1.915.0 ± 2.120.217.4
Spain9108240814.1 ± 2.718.0 ± 0.917.218.7
UAE2021192149724.8 ± 1.224.0 ± 1.026.224.7
UK92215728718.6 ± 3.316.6 ± 2.323.719.2
Uruguay72113824018.0 ± 1.515.6 ± 2.120.618.9
USA111761117614.3 ± 3.315.5 ± 1.719.519.6

Elimination data

Data for 4326 endurance ride starters were collected, of which 1991 finished the ride (46.0%). The most common reason for not completing the ride was elimination (1986/4326, 45.9%), although 349 horses were retired (8.1% of all started horses). The rates for completion, elimination and retirement in each country are shown in Table 3. The highest completion rates were recorded in Australia (63.9%), USA (63.6%) and South Africa (57.6%). There were 3 countries, where fewer horses completed the ride than were eliminated: the UAE (34.1 and 56.6%, respectively), Uruguay (46.3 and 50.8%) and UK (43.2 and 49.8%).

Table 3. The number of horses that started and completed the ride or were retired or eliminated at Féderation Équestre International endurance rides of ≥100 km in 2008 in 9 countries
CountryStarted nCompleted n (%)Retired n (%)Eliminated n (%)
AllLamenessMetabolicOther
  1. The percentages indicate the proportion of all started horses.

Australia15599 (63.9)1 (0.7)55 (33.7)46 (29.7)5 (3.2)3 (1.9)
France1029565 (54.9)85 (8.3)380 (36.9)297 (28.9)63 (6.1)20 (1.9)
Italy291148 (50.9)21 (7.2)122 (41.9)81 (27.8)22 (7.6)19 (6.5)
South Africa243140 (57.6)17 (7.0)86 (35.4)61 (25.1)16 (6.6)9 (3.7)
Spain408180 (44.1)48 (11.8)180 (44.1)110 (27.0)51 (12.5)18 (4.4)
UAE1497510 (34.1)140 (9.4)847 (56.6)544 (36.3)255 (17.0)45 (3.0)
UK287124 (43.2)20 (7.0)143 (49.8)113 (39.4)17 (5.9)13 (4.5)
Uruguay240111 (46.3)7 (2.9)122 (50.8)83 (34.6)29 (12.1)10 (4.1)
USA176112 (63.6)10 (5.7)54 (30.7)45 (25.6)9 (5.1)0 (0)

Lameness was the most frequent cause of elimination in all countries: 1375 horses were eliminated for lameness, which represents 69.2% of all eliminations and 31.8% of all entered horses. Of the 4326 entered horses, 467 horses were eliminated for metabolic reasons (10.8%), accounting for 23.5% of all eliminations. The ratio between elimination for lameness and metabolic reasons varied between countries, but lameness was at least twice as common as other reasons for elimination in all countries.

Analysis of risk factors

Descriptive results revealed that the proportion of horses eliminated for lameness and metabolic reasons was lowest in South Africa (25.1% of all entries) and Australia (3.2% of all entries). Therefore, to aid interpretation of the multivariable models, the analyses for the 2 different outcomes used a different baseline country: South Africa for the lameness model and Australia for the metabolic model. The 4 variables that were tested for association with elimination for lameness or metabolic reasons are listed in Tables 4 and 5. Multivariable analyses revealed that the risk of elimination due to lameness or for metabolic reasons was significantly associated with the country. Multivariable analysis revealed that horses competing in rides held in the UK (odds ratio [OR]= 2.11, P<0.001), UAE (OR = 1.72, P = 0.007) and Uruguay (OR = 1.69, P = 0.013) were significantly more likely to be eliminated for lameness than those competing in South Africa. Multivariable analysis revealed that if the number of entries was ≥80, then horses were at an increased risk of elimination for lameness (OR = 1.60, P = 0.002), than in rides where the number of entries was <80 (Table 4).

Table 4. Results of univariable and multivariable logistic regression presenting the effect of variables on elimination for lameness at Féderation Équestre International endurance rides of ≥100 km in 2008 in 9 countries
VariableCases n (%)Controls n (%)Odds ratio95% confidence intervalsP value
  • Reference category.

Univariable analysis     
Young rider     
 No1244 (41.7)1741 (58.3)1.000.644–0.9960.046
 Yes143 (36.4)250 (63.6)0.80
Number of entries    <0.001
 <80939 (36.7)1617 (63.3)1.001.759–12.418 
 ≥80448 (54.5)374 (45.5)2.07
Number of entries (continuous)  1.0081.006–1.010<0.001
Number of entries (quadratic term)  1.001.000–1.0000.147
Distance     
 ≤120 km938 (40.6)1375 (59.4)1.070.922–1.2380.378
 >120 km449 (42.2)616 (57.8)
Distance (linear relationship)  1.000.997–1.0040.871
Distance (quadratic relationship)  1.001.000–1.0010.085
Country     
 South Africa61 (30.3)140 (69.7)1.00  
 Australia47 (32.2)99 (67.8)1.090.688–1.7250.714
 France296 (34.4)565 (65.6)1.200.863–1.6760.276
 Italy81 (35.4)148 (64.6)1.260.838–1.8830.270
 Spain110 (37.9)180 (62.1)1.400.956–2.0570.083
 UAE550 (51.9)510 (48.1)2.481.790–3.422<0.001
 UK114 (47.9)124 (52.1)2.111.423–3.128<0.001
 Uruguay83 (42.3)113 (57.7)1.691.115–2.5480.013
 USA45 (28.7)112 (71.3)0.920.583–1.4580.073
Multivariable analysis     
Number of entries     
 <80939 (36.7)1617 (63.3)1.601.194–2.1370.002
 ≥80448 (54.5)374 (45.5)
Country     
 South Africa61 (30.3)140 (69.7)   
 Australia47 (32.2)99 (67.8)1.090.688–1.7250.714
 France296 (34.4)565 (65.6)1.200.863–1.6760.276
 Italy81 (35.4)148 (64.6)1.260.838–1.8820.270
 Spain110 (37.9)180 (62.1)1.400.956–2.0570.083
 UAE550 (51.9)510 (48.1)1.721.159–2.5560.007
 UK114 (47.9)124 (52.1)2.111.423–3.128<0.001
 Uruguay83 (42.3)113 (57.7)1.691.115–2.5480.013
 USA45 (28.7)112 (71.3)0.920.583–1.4580.729
Table 5. Results of univariable and multivariable logistic regression presenting the effect of variables on elimination for metabolic reasons at Féderation Équestre International endurance rides of ≥100 km in 2008 in 9 countries
VariableCases n (%)Controls n (%)Odds ratio95% confidence intervalsP value
  • Reference category.

Univariable analysis     
Young rider  0.740.531–1.0310.075
 No433 (19.9)1741 (80.1)
 Yes46 (15.5)250 (84.5)
Number of entries  4.293.345–3.345<0.001
 <1001171 (39.2)1813 (60.8)
 ≥100216 (54.8)178 (45.2)
Number of entries (linear relationship)  1.021.013–1.018<0.001
Number of entries (quadratic relationship)  1.001.000–1.000<0.010
Distance  0.750.594–0.937<0.001
 ≤120 km359 (20.7)1375 (79.3)
 >120 km120 (16.3)616 (83.7)
Distance (continuous)  0.990.989–1.0000.041
Distance (quadratic term)  1.001.000–1.0000.928
Country     
 Australia5 (4.8)99 (95.2)   
 France65 (10.3)565 (89.7)2.280.895–5.7990.084
 Italy22 (12.9)148 (87.1)2.941.079–8.0320.035
 South Africa16 (10.3)140 (89.7)2.270.803–6.3810.123
 Spain51 (22.1)180 (77.9)5.612.168–14.516<0.001
 UAE264 (34.1)510 (65.9)10.254.123–25.478<0.001
 UK17 (12.1)124 (87.9)2.710.968–7.6150.058
 Uruguay30 (21.0)113 (79.0)5.261.964–14.069<0.001
 USA9 (7.4)112 (92.6)1.590.516–4.9070.419
Multivariable analysis     
Number of entries  2.171.604–2.939<0.001
 <1001171 (39.2)1813 (60.8)
 ≥100216 (54.8)178 (45.2)
Country     
 Australia5 (4.8)99 (95.2)   
 France65 (10.3)565 (89.7)2.280.895–5.7990.084
 Italy22 (12.9)148 (87.1)2.941.079–8.030.035
 South Africa16 (10.3)140 (89.7)2.260.803–6.380.123
 Spain51 (22.1)180 (77.9)5.612.168–14.516<0.001
 UAE264 (34.1)510 (65.9)7.282.894–18.295<0.001
 UK17 (12.1)124 (87.9)2.710.968–7.6150.058
 Uruguay30 (21.0)113 (79.0)5.261.964–14.069<0.001
 USA9 (7.4)112 (92.6)1.590.516–4.9070.042

Multivariable analyses revealed that with the exception of France, South Africa and the USA, horses in all other countries had increased risk for elimination for metabolic reasons than those competing in Australia. The highest risks for elimination were recorded in the UAE (OR = 7.28, P<0.001), Spain (OR = 5.61, P<0.001), Uruguay (OR = 5.26, P<0.001) and Italy (OR = 2.94, P = 0.035). Multivariable analysis (Table 5) showed that the number of entries in the class was also significantly associated with the risk of elimination due to metabolic reasons. The best model fit was found for a cut-off of classes with <100 or ≥100 entries. Horses competing in classes with ≥100 entries had more than twice the risk of elimination due to metabolic reasons (OR = 2.17, P<0.001) compared with horses competing in classes with fewer entrants (Table 5).

Univariable analysis showed that young riders' horses were less likely to be eliminated for lameness (OR = 0.8, P = 0.046) than seniors' horses, although this association did not retain significance in the multivariable analysis. No evidence was found for a significant effect of distance on elimination for either lameness or metabolic reasons in the multivariable analyses.

Discussion

  1. Top of page
  2. Summary
  3. Introduction
  4. Materials and methods
  5. Results
  6. Discussion
  7. Acknowledgements
  8. Conflicts of interest
  9. Manufacturer's address
  10. References

To date, this is the largest study describing completion rates and risk factors for eliminations due to lameness and metabolic reasons from endurance rides in different countries. In accordance with our hypothesis, the country of the ride had a significant effect on the risk of elimination due to both lameness and metabolic reasons. The number of entries in the ride was also significantly associated with the risk of elimination due to either lameness or metabolic reasons.

The popularity of endurance riding has been growing during recent years, accompanied by increasing numbers of riders and horses competing at international level. Despite the high number of horses involved and the constantly debated welfare issue, few publications have reported research into endurance horses. Most studies have focused on metabolic problems (Sloet van Oldruitenborgh-Oosterbaan et al. 1991; Robert et al. 2002; Schott et al. 2006; Fielding et al. 2009), nutrition (Sampieri et al. 2006) or gait analysis (Munoz et al. 2006; Riber et al. 2006). To our knowledge, to date, no large scale epidemiological studies have been performed in endurance horses. The only published data on completion rates in endurance rides in different countries are in an abstract by Marlin et al. (2008). The number of eliminations and horses treated at the ride were assessed in 8 global regions during the period 2005–2007. Similar to our study, they used the FEI database and selected 2 rides of 120 km and 2 rides of 160 km randomly from each region, assessing a total of 1651 horse starts. The study of Marlin et al. (2008) revealed an increase in elimination for lameness over a 3 year period, but did not assess risk factors for elimination.

The retrospective study reported here had the aim of providing preliminary data, which could be used to design future prospective studies. It was logical to first focus on the rides (and not on training), because data relating to the number of entries and ride distances are available for all FEI rides. Specific information on individual horses (e.g. case details, weight carried, racing history, individual speed), weather and terrain conditions, can only be obtained prospectively and were therefore not included in this study. When assessing the pooled data from all included countries, only 46.0% of horses finished the ride. Elimination rates varied between countries. This may be attributable to a number of factors, including terrain, weather, training, riding (e.g., speed and fitness), and quality of veterinary control at the ride. All of the above require further detailed investigation.

Elimination for lameness

In all countries, lameness was the most common reason for elimination, which is in agreement with results of previous studies (Robert et al. 2006;Marlin et al. 2008). The highest elimination rates were recorded in the UK, UAE and Uruguay. It has been suggested anecdotally that the number of orthopaedic injuries has been increasing, possibly related to increasing speed. Ride specific information on terrain and environmental conditions needs to be assessed in a large-scale global study to identify whether these factors are associated with increased risk for elimination for lameness and specific orthopaedic injuries.

In the multivariable model, horses starting in endurance rides with ≥80 starters were at increased risk of elimination for lameness than those competing in rides with fewer starters. The reason for this association is not clear and warrants further investigation; however, it is possible that a large number of competitors have an effect on racing strategy and the speed at which individual horses are ridden, which we speculate may result in increase of lameness occurrence and subsequent elimination. Univariable analysis revealed that young riders' horses were at a decreased risk for elimination for lameness than seniors' horses. This result was only significant in the univariable analysis and should not be over-interpreted.

Elimination for metabolic reasons

Multivariable analysis showed that several countries had increased risk for horses being eliminated for metabolic reasons compared with Australia, where the lowest elimination rate for metabolic reasons was recorded. Strenuous exercise performed in hot and humid conditions is more likely to lead to electrolyte imbalance and dehydration than in dry cool conditions (Marlin et al. 1996; Marlin and Nankervis 2002). This may progress to clinical metabolic problems (Flamino and Rush 1998). It is therefore not surprising that elimination for metabolic reasons in the UAE and Mediterranean countries was common. However, further analysis is needed to investigate the effect that temperature and humidity have on elimination for metabolic reasons. It has to be borne in mind that the current study assessed the affect of each country in general over a period of a year. There are countries (e.g. Italy and Spain) where endurance rides are held in both summer and winter months in different environmental conditions, whilst in other countries where summer is hot (e.g. Australia and South Africa), most FEI rides are held in cooler months.

Horses competing in rides with ≥100 entrants were at an increased risk of elimination due to metabolic reasons (Table 5), compared with horses competing in rides with fewer entrants. The different cut-off point used for the variable of number of entries in the 2 multivariable models resulted from comparisons of the model fits that resulted from using different cut-off levels. It is hypothesised that rides with more entrants might be ridden more ‘competitively’ and at faster speeds, contributing to an increased risk of eliminations due to metabolic problems. However, analysis of the average speed of individual horses is needed to test this hypothesis. If there is a large number of horses in a class, it is also possible that there is also a larger number of horses that are unfit or unsuitable for the ride, which may also result in higher number of eliminations.

The ratio between eliminations for metabolic reason and lameness has been considered by some endurance veterinarians a measure of the general welfare of the horses. This seems to be supported by the results of the study reported here, which recorded the lowest number of elimination for metabolic reasons in countries with the highest completion rates and a high proportion of lameness for all eliminations. However, the concept that metabolic problems represent a more serious welfare issue than lameness has changed in the past few years. Riders, trainers and veterinarians are finally realising that musculoskeletal injuries can be career-ending or even life-threatening in extreme cases (J. Bryant, personal communication). The authors of the current paper presented here believe that lameness and orthopaedic injuries are equally important to the horses' welfare as metabolic problems.

Limitations of the study

Nine countries were included in this study, which allowed assessment of 97 out of the 188 FEI endurance events running classes of ≥100 km that were held globally in 2008. Selection of the countries was not randomised, which may have influenced the results, but the aim was to include countries where endurance is popular or considered to have great tradition in endurance riding, in addition to including all 5 continents.

From the FEI website, only the winning speed could be obtained; the speed for all horses was not available. We did not assess the winning speed as a risk factor, because it may not reflect the speed of the eliminated horses. Detailed analysis is needed to assess data for each horse's average speed and the stage of the ride at which the horse is eliminated.

Objectivity and standardisation of the veterinary examination has been a subject of debate and is regularly discussed at scientific meetings and amongst endurance veterinarians. Despite training of veterinarians and anonymous voting by 3 veterinarians for each elimination, there is inevitable subjectivity involved in each final decision. This may have influenced the results of the current study and will do so in the future; in countries where veterinary scrutiny is closer, elimination rates may be higher.

It has to be taken into account that finishing a ride and completion rates do not necessarily reflect the welfare of the horses. It may be those rides with higher elimination rates are removing the horses before they are more seriously compromised and in fact may reflect better attention to welfare issues. In a prospective study, problems occurring shortly after the ride will also have to be assessed.

Further studies

To identify risk factors that can be used to improve the welfare of endurance horses, and to help to base the FEI ride regulations on evidence-based data, a large-scale, worldwide research study is needed to document the frequency of occurrence of eliminations. Risk factors for eliminations and specific injuries that result in elimination need to be determined, and lameness and metabolic problems that occur shortly after a ride need to be evaluated. This study was carried out as a pilot study for a prospective study that aims to investigate risk factors for lameness and specific orthopaedic injuries resulting in elimination from elite endurance rides. The increasing number of eliminations for lameness clearly supports the need for such a study.

The current study showed that elimination for lameness and metabolic reasons varied both between countries and with the number of horses in the ride. Further studies are needed to assess more specific risk factors, in order to provide objective data that can help planning racing schedules and serve as a basis for regulations, ultimately improving both the welfare of endurance horses and the public perception of the endurance discipline.

Acknowledgements

  1. Top of page
  2. Summary
  3. Introduction
  4. Materials and methods
  5. Results
  6. Discussion
  7. Acknowledgements
  8. Conflicts of interest
  9. Manufacturer's address
  10. References

We would like to thank the many endurance veterinarians and FEI officials, whose thoughts and experience were essential for initiation of this study. We thank Dr Jim Bryant for his constructive criticism of the manuscript. Annamaria Nagy is grateful for the support and teaching she has received from Drs Frederic Barrelet, Jim Bryant, Martha Misheff and Brian Sheahan.

References

  1. Top of page
  2. Summary
  3. Introduction
  4. Materials and methods
  5. Results
  6. Discussion
  7. Acknowledgements
  8. Conflicts of interest
  9. Manufacturer's address
  10. References
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