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The effect of a horse’s racing career on the success in eventing post retraining

Author Names: Sarah Price (BSc (Hons) Equine Science) and Rachel Collins

 

Abstract

Retraining racehorses is proven to be popular within the equine industry, especially due to known good performance in eventing due to factors such as conformation and training methods enabling strengthening of the hors’es psychological and physiological state from a young age. This research aimed to determine whether the effects of the racing career have an impact on the success in eventing post retraining. Retrospective data was analysed from online competition records to determine whether length of racing career, the number and type of races completed or the time between racing and eventing careers affected the highest level completed, Foundation Points (FP) or Grading Points (GP) achieved during eventing careers. Of the racehorses foaled in 2000 that had competed in racing (n=3869), 2.8% (n=107) had completed a minimum one event after their racing career, suggesting high wastage rates. Negative correlations were found between the number of flat races and total FP achieved (p=0.018), FP achieved at BE100 level (p=0.036) alongside time between racing and eventing careers and highest eventing level completed (p<0.001) or FP achieved at BE100 level (p=0.029). Significant positive correlations were found between the number of jump races and total FP (p=0.001), or FP achieved at BE100 level (p=0.036). Horses with longer careers achieved more FP at BE100 level (p=0.040), those completing more jump races achieved more FP (p=0.045) and FP at BE100 level (p=0.034) and those with shorter time between racing and eventing careers (p=0.024) reached higher eventing levels. Overall, the findings suggest that horses who compete for a longer time, completing more races, especially jump racing, with shorter transitions into eventing, often achieve greater success during the eventing career. This research has created a baseline for more in-depth future research to expand upon this knowledge. Understanding which horses are successful when retraining from racing to eventing could improve welfare and health of retired racehorses, alongside enhancing performance which could lead to improved Team Great Britain (GB) success.         

 

1.0 Introduction

1.1 Industry focus on retraining racehorses for eventing

Retraining Thoroughbreds following their racing career, especially to eventing, is anecdotally reported as common and successful within the equine industry (BHA, 2016; Crossman, 2010). The popular Retraining of Racehorses (RoR) eventing series was launched in 2000 to support the retraining of racehorses to other disciplines from grassroots to elite level (RoR, 2017; Crossman, 2010); registering more than 12,500 horses as active in disciplines including eventing (BHA, 2016). There is limited research into the wider application of retraining and competing at different levels, specifically regarding success and potential barriers to success for horses within the sport. To improve the chance of ex-racehorses having successful eventing careers alongside increasing progression to elite level to enhance Team Great Britain (GB) performance on national and international stages, future research would be beneficial.

Morscher (2010) found that Thoroughbred horses were preferred for eventing during long format as other horses did not have the required stamina and speed, especially for elite level. However, in the new short format, more than half of interviewed riders thought Irish Sport Horse crossed with Thoroughbred to be the most suitable breed, with pure Thoroughbreds the second favourite (Morscher, 2010). The continued desire for Thoroughbred horses shows that research to identify and expand upon best practice for eventing an ex-racehorse successfully as well as maintaining their health and welfare would be beneficial to industry.

Ex-racehorses have recently featured as a prominent part of Team GB, highlighted by ex-racehorse, Arctic Soul, being longlisted for the Rio de Janeiro Olympic Games 2016 after coming third at Badminton International CCI**** Horse Trials in the preceding months (BE, 2016a, BE, 2016b). The industry requires a baseline understanding of how ex-racehorses progress into eventing including the selection of elite horses, to expand knowledge of the links between the racing and eventing industries. Improved understanding of what makes a successful transition onwards from racing can enable riders, owners, and trainers to make the best possible decision when choosing competition horses, especially when selecting horses for specific reasons such as elite competition.

 

1.2 Thoroughbred wastage

Increased knowledge of how racing career longevity and associating factors impact the suitability of horses to transition to an eventing career, alongside reasons behind horse choice in industry could help to reduce wastage figures within the equine industry (Ducro et al., 2009; Burns et al., 2006). Limited progress has been made during the past twenty years in addressing the racehorse wastage issue, primarily due to the lack of purpose designed studies focusing on wastage and the relevant preventative measures, such as entering other appropriate disciplines (Verheyen, 2012). High wastage figures from the racing industry link to the competitive and profit-oriented nature of the sport, alongside large numbers of horses not achieving the desired results on the track (Stowe and Kibler, 2016; Mayberger, 2011). Introducing discipline specific research on suitability of retraining racehorses for eventing and patterns of success could begin to reduce wastage, especially considering improvement of suitable retirement periods for racehorses to promote long and successful future careers.

Wastage within the equine industry has many financial implications; as a largely underfunded industry it is important to increase understanding of the issue and reduce the occurrence (Ducro et al., 2009; Burns et al., 2006). The racing sector acquires more funding than any other part of the industry, meaning the effect of media and positive perception of the sport is of high priority (Collins et al., 2008). Controlling wastage to reduce the negative implications and perceptions regarding welfare of racehorses and the bad press surrounding the sport could in turn improve wider perceptions of the sport, and encourage further sponsorship and support (Collins et al., 2008). Seeing racehorses transition for a successful second career could benefit viewing figures, encouraging wider involvement in both racing and eventing.

Mayberger (2011) explains a potential cause for racehorse wastage during retraining to be associated with the levels of experience, commitment, and determination to become successful in their retrained career, compared to that of other horses of the same age and respective training experience. Research to develop understanding of which horses have potential for successful eventing careers could help to reduce some difficulties in training due to their natural suitability. Within eventing, dressage, show jumping and endurance horses, Sloet van Oldruitenborgh‐Oosterbaan et al., (2010) found 55% of careers ended due to being sold, often linked to unsatisfactory performance, which is known to make up a large portion of wastage within equestrian sport. It is important to understand both the horse’s suitability for eventing and the current equine market with regards to what are considered appealing traits according to owners, riders, and trainers within the sport to improve understanding of the reasons behind wastage versus success (Hennessy et al., 2008).

 

1.2.1 Strain during training the young racehorse

It has been suggested that competitive careers could end early due to strain during training the young skeleton causing injuries, or predisposition to injury further into ridden careers (Burns et al., 2006). However, it has also been evidenced that horses racing from younger ages had longer careers, consistent with human research demonstrating that exercising with a growing skeleton has beneficial effects on long-term fracture resistance (Verheyen, 2012). The differing evidence highlights the need for research specifically on longevity of racing career relating to the impact on future health and career potential, for example eventing retraining. This has not been investigated thoroughly leaving many trainers, owners, and riders without definitive guidance on the best practice for enhancing health, fitness, and performance of the ex-racehorse.

Thoroughbreds can start training from two years old and it has been found that within racing, those starting training younger had longer and more successful careers, highlighting the need for research to be continued, enabling further conclusions to be drawn in this area (Martig et al., 2014; Tanner et al., 2013; Velie et al., 2013). Training the young skeleton must be done gradually, allowing remodelling to take place, to ensure the bones are strengthened and not damaged to provide long term benefits to skeletal health (Martig et al., 2014). Exercising the young skeleton is considered to be protective to joints and enhance bone strength, which is potentially beneficial to horses undergoing two physically demanding careers where large forces will be taken through the limbs (Firth et al., 2011; Kawcak et al., 2010). Understanding whether longevity of career impacts the horse’s long term career is vital to prevent suffering and ensure suitable horses are selected for competitive careers.

Positive effects of exercising the young horse have been noted in all equestrian sports, although more heavily so in racing due to young horses being frequently exercised (Rogers et al., 2012). Proven benefits on the homogeneity, strength and quality of articular cartilage were found in Thoroughbred horses exercising at younger ages (Dykgraaf et al., 2008) and horses exercising at pasture showed signs of musculoskeletal disorders earlier than horses in structured training from 18 months old (Rogers et al., 2008). The benefits from early race training strengthening the musculoskeletal system could enable horses to train and compete for longer, potentially enabling higher levels of success to be reached in eventing.

Firth et al., (2011) also found significantly better bone strength and tolerance to increased loads in Thoroughbreds exposed to increased exercise prior to race training, which could reduce the risk of fractures, early breakdown or other musculoskeletal injuries during racing and eventing careers. Injuries involving bone were found to cause large portions of breakdown within racehorses (Martig et al., 2014), therefore training the young horse appropriately could benefit health, career longevity and potential success, although being mindful of the risks associated is also vital.

 

1.3 Retraining Thoroughbred horses

Thoroughbreds are physiologically capable of retraining for a successful eventing career due to natural suitability to the discipline, such as power and speed (Stowe and Kibler, 2016). International success is highlighted by horses such as Director General, winner of the RoR Elite Eventing Performance Award (RoR, 2016). Training throughout the racing and eventing career will emphasise speed and stamina; focusing training on low intensity canter exercise rather than high-speed exercise decreases the risk of wastage through skeletal injury and benefits joint health (Reed et al., 2013). Most racehorses are thought to retire at an age that allows them to pursue future careers successfully, due to the existing training and musculature providing a good basis for future training in the form of reducing injury risk via superior musculoskeletal strength and cardiorespiratory performance (Stowe and Kibler, 2016). Analysis of 17,962 competition results in dressage, show jumping, and eventing determined that horses competing in more than one discipline, especially those starting younger, had longer competitive careers (Braam et al., 2011), highlighting the possibility of increasing ridden and competitive careers through encouraging retraining after retirement from one area within equestrian sport, such as racing to promote good health and welfare.

Conditioning the racehorse for an eventing career should include an appropriate level of physiological and psychological stress to prepare them for the demands of competition, increasing the potential for success throughout the competing career (McKenzie, 2017). Thoroughbreds are likely to need longer in the habituation phase of retraining due to their high sensitivity, reactivity, and anxiety, which should be less present than in racing where the flight response is important (Lloyd et al., 2008). Assessing appropriate training prior to eventing is vital to ensure longevity of the career, enabling horses to be successful. Graf et al., (2013) explain that when sold, horses are often chosen for good temperament over physiological traits. This highlights the importance of investigating how racing career longevity could impact the duration, type and success of retraining required before achieving competition success in eventing, where limited research currently exists.

 

1.3.1 Physiological adaptations

All horses should be trained with a combination of schooling to develop neuromuscular coordination and conditioning for physiological and structural adaptation of the body systems, which can be transferred from racing to eventing (Castejon-Riber et al., 2017). However, it is important to consider the length of time required for the musculoskeletal system to adapt to the requirements of the new career to reduce the risk of injury and increase performance (RoR, 2018). It is vital to specifically train systems such as muscular, skeletal and cardiorespiratory to ensure the horse is physiologically strong and capable of carrying out the required work, to avoid strain that could lead to injury, poor performance or poor welfare (Castejon-Riber et al., 2017). Understanding the patterns between type of racing career and the period of retraining would aid production of training plans and further research into enhancing the Thoroughbred’s performance in both racing and eventing.

Skeletal muscle mass of Thoroughbreds is high at 53-57%, compared to 42% in ‘non-athletic’ breeds (Rivero and Hill, 2016). In response to training, protein constituents per muscle fibre increase creating an increased muscle mass, thus generating increased potential power output, creating higher performance potential (Rivero and Hill, 2016). Thoroughbreds have shown increases in muscle fibre type 2A in the forelimbs through training thus enabling enhanced locomotion and speed, however the hind limb is considered the key mechanism of propulsion, with the increase of type 2X fibres enhancing this it will also benefit the horse during the cross-country phase of eventing (Rivero and Hill, 2016; Kawai et al., 2009). Aerobic and anaerobic capacities can also be influenced by training, which should be enhanced through race training due to the goal of training the racehorse, giving horses an improved start to retraining for eventing (Jang et al., 2017).

 

1.4 Thoroughbred musculoskeletal health

Veterinary problems prevented 35.1% of horses from re-registering with British Eventing (BE) in a study conducted by O’Brien et al., (2005), highlighting the importance of understanding which horses are also not suitable for an eventing career post racing, to hopefully reduce this figure in the future. Horses that are older at their first race or have raced for over five years have demonstrated higher risk of injury (Martig et al., 2014; Ducro et al., 2009; Henley et al., 2006), showing the importance of understanding the interaction between factors in the racing career that could impact eventing performance. Increased injury risk is specified for horses competing in jump racing compared to flat racing, alongside an increased risk when running a different type of race for the first time (Henley et al., 2006).

It is also important to understand which horses are most likely to have experienced injuries during their careers to prevent horses being put under excessive strain during retraining. For example, horses in jump racing careers are older and due to the fatigue damage build-up throughout the longer ridden career they are at higher risk of injury, such as stress fractures due to high pressure through the distal limbs for longer periods (Martig et al., 2014).  Superficial digital flexor tendonitis is common in racehorses due to pressures on the distal limb, however due to strain caused by the cross-country phase it is important to consider horses at higher risk, for example jump racing, and ensure training and future careers are considered appropriately (Witte et al., 2016). Musculoskeletal injury is considered the primary cause of wastage within sport horses, with conformational predisposition to lameness thought to impact heavily (Ducro et al., 2009).

 

1.4.1 Conformation

It is known that Thoroughbreds make good event horses due to their athleticism and speed, however, considering conformation is important to reduce the risk of injury caused by strain to the limbs and back in particular during eventing (Dyson, 2002). Performing at elite level competition is thought to require stronger conformation, especially in the limbs and more specifically distal limbs (Ducro et al., 2009). Larger angles of the hock and stifle joints have been linked to improved jumping ability (Holmström and Philipsson, 1990), which could link horses with successful jump racing careers to possible eventing success due to natural potential. Ideally racehorses should be physically lightweight to reduce the strain on the body, especially the distal limb; the third metacarpal having smaller width has also been linked to sport horse ability, showing similarities in desired conformation (Holmström and Philipsson, 1990). Knowing that the horses are physiologically well matched could encourage those in industry to choose ex-racehorses for eventing, further evidence of potential for success could also increase appeal, therefore lessening wastage.

Conformational research in racehorses is often focused on development of young horses or injury risk, however significant conformational differences have been found between National Hunt (NH) and flat racehorses (Weller et al., 2006). NH horses presented significantly larger on average in neck, forelimb and pelvis length, tibia circumference and most notably so in front and hind hoof circumference compared to flat racehorses (Weller et al., 2006). It is important to ensure the larger hind hoof circumference does not negatively impact the horse if farriery is not suitable, as uneven hooves are considered undesirable due to the potential of limiting competition career longevity (Ducro et al., 2009). NH horses have larger frames, however, it is considered a possibility for this to be because of widespread anecdotal evidence that horses participating in jump racing should be bigger than flat racehorses, influencing the sales market (Weller et al., 2006). However, Weller et al., (2006) study used a sample of horses from only one yard, meaning the type of horses on that yard may be chosen specifically due to conformational preferences of the owners or trainers, potentially based on previous success rates, potentially impacting the results.

 

1.5 Research aim

The aim of this study is to determine whether the effects of the racing career have an impact on the success in eventing post retraining.

 

1.5.1 Objectives

(1) To investigate whether the longevity of a racehorse’s career influences the level of competition reached through British Eventing post retraining.

  • H0: The longevity of a racehorse’s career will have no association with the level of competition reached through British Eventing post retraining.
  • H1: The longevity of a racehorse’s career will have an association with the level of competition reached through British Eventing post retraining.

 

(2) To investigate whether the longevity of a racehorse’s career influences the number of foundation and grading points accumulated through British Eventing post retraining.

  • H0: The longevity of a racehorse’s career will have no association with the number of foundation and grading points accumulated through British Eventing post retraining.
  • H1: The longevity of a racehorse’s career will have an association with the number of foundation and grading points accumulated through British Eventing post retraining.

 

(3) To investigate whether the type of races run influences success in eventing post retraining.

  • H0: The longevity of a racehorse’s career will have no association with the level of competition reached through British Eventing post retraining.
  • H1: The longevity of a racehorse’s career will have an association with the level of competition reached through British Eventing post retraining.

 

(4) To investigate whether the time between racing and eventing careers influences success in eventing post retraining.

  • H0: The time between racing and eventing careers will have no association with the number of grading points accumulated through British Eventing post retraining.
  • H1: The time between racing and eventing careers will have an association with the number of grading points accumulated through British Eventing post retraining.

 

2.0 Methods

2.1 Study design

To address the aim of the study, quantitative retrospective data from 2000 to 2017 were collected from Weatherbys, Weatherbys Point to Point, following approval to use the data, and open data from British Horseracing Authority (BHA), Racing Post and British Eventing (BE) online databases to gain full data on all aspects of the horses’ competition records, which has been proven as a performance parameter from previous research (BE, 2017; BHA, 2017; Kearsley et al., 2008; Olsson et al., 2008; Racing Post, 2017; Weatherbys, 2017; Weatherbys Point to Point, 2017). Data were recorded and coded in Microsoft Office Excel 2016, before data analysis was undertaken on IBM SPSS Statistics 24; all data were kept confidential and securely in accordance with The Data Protection Act (1998).

Data obtained from Weatherbys included a list of every horse foaled in 2000 in Great Britain that had successfully completed one or more race (n=3869), the names were checked against the BE database to compare full name, dam and sire of the horse to determine whether they had competed in affiliated eventing. Horses that had competition records for racing and eventing then had data collected for the date of first and last race completed, number of runs and the type of races run collected from BHA, Racing Post and Weatherbys Point to Point.  Data collection from British Eventing included the date of first event completed, highest competition level finished, number of BE Foundation Points (FP) and the level at which they were achieved (BE90 or BE100) alongside the number of BE Grading Points (GP) and the level at which they were achieved (Novice, CIC*, CCI*, Intermediate, CIC**, CCI**, Advanced, CIC***, CCI*** or CCI****) (BE, 2018).

 

2.2 Sampling

The population of racehorses foaled in 2000 in Great Britain (GB) that completed minimum one race (n=3869) was gained from Weatherbys by homogeneous sampling (Etikan, 2016). Inclusion and exclusion criteria were enforced to ensure data was relevant and accurate for analysis to limit the impact of extraneous variables on the results (Smith, 2010). For example, large variations of age could affect the data available regarding career length, retraining and success due to incomplete databases, or horses having unfinished careers. The inclusion criteria consisted of horses foaled in 2000 that had completed a minimum of one competition in racing and affiliated eventing, to enable full competition career data to be gathered. The exclusion criteria specified horses that had not competed in both disciplines or competed in eventing prior to competing in racing.

The sample of horses foaled in 2000 was chosen as BE and The Fédération Equestre Internationale (FEI) changed the competition format from 2004 onwards by removing the roads and tracks phase, significantly changing the athletic demand of the sport (BE, 2009a). Some horses may have been more successful in one version of the sport than the other due to individual variation, therefore standardising age removed the impact of this when determining eventing success. Horses are not able to compete with BE until four years old for four-year-old classes comprising of a different format without a cross country phase, or five years old for all other standard competition, which was recorded during this study (BE, 2009b). All horses in the sample were competing in the same format regardless of the start and end dates of their eventing career. Horses that were foaled in earlier years could have competed in the previous or current format if they evented at a younger age. Horses foaled in more recent years could be at the start of their eventing career and not yet reached peak success, both of which would have influenced the results.

 

2.3 Data analysis

To assess the quantitative data collected, descriptive statistics including mean, standard deviation (SD), median and range were used to create an overview of the data, before inferential statistics were used to assess the research objectives relating to correlations and differences found (Foster et al., 2015) through the following statistical tests. Kolmogorov Smirnov Test (KS Test) for normality was carried out on all data to determine whether it was parametric (p>0.05) or non-parametric (p<0.05), and therefore which test must follow (Dytham, 2011).

Spearman’s Rho test for correlation was carried out on all variables as they were non-parametric following the KS test (Field, 2013), to determine the significance, strength, and direction of the correlation and whether to accept or reject the null hypotheses (Dytham, 2011). A significance output (p-value) of less than 0.05 indicated a relationship between the two variables; the correlation coefficient, between -1 (negative correlation) and +1 (positive correlation), determined the direction and strength of the relationship between the two variables (Elliott and Woodward, 2016; Dytham, 2011). Effect size is determined by the correlation strength; strong linear relationships were indicated by a correlation coefficient of +/- ≥0.51, moderate relationships at +/-0.31-0.50, weak relationships at +/-0.10-0.30 and no correlation +/-0.10 (Elliott and Woodward, 2016).

To test for difference following the KS test, the Kruskall Wallis Test was carried out on the non-parametric variables (Field, 2013). The output determined the significance, whether a difference was found, if so where the difference was found and therefore whether to accept or reject the null hypotheses (Field, 2013). The significance values of each test were noted, with p<0.05 showing significance; however, the adjusted significance values were taken as the true significance as the data had undergone the Bonferroni correction for multiple tests via pairwise comparisons (Field, 2018). The post-hoc tests in the form of pairwise comparisons compared all different combinations of the groups to provide the adjusted significance values and determine if there is significance between any groups, where the significance lies and to what extent (Field, 2018). Adjusted significance values of p<0.05 demonstrated a significant difference in the distribution of data across the specified categories (Dytham, 2011).

 

3.0 Results

3.1 Descriptive statistics

Of the 3869 racehorses that made it to the track, 3.6% (142 of 3869) registered with BE and 81.6% of these (116 of 142) completed a minimum of one eventing competition. Horses that competed in eventing before their racing career were excluded from the study (n=8), alongside those only competing in Jumping and Style (JAS) competitions (n=1), leaving 107 horses valid for analysis. The racing career length median was 12 months (IQR=24) with a range of <1-71; see figure 1. The median number of racing runs was 6 (IQR=7.5) with a range of 1-46; throughout the horses’ careers, 17.8% (19 of 107) ran both flat and jump races, 29.9% (32 of 107) only ran flat races and 52.3% (56 of 107) only ran jump races; see figure 2.

 

Figure 1: Length of horses’ racing careers (months)

Figure 1
Figure 2: Type of races completed during racing careers.

Figure 2

 

The time between racing and eventing careers had a range of 2-124 months, with a median of 24 (IQR=24). The highest BE level completed was predominately BE100 at 40.2% (43 of 107), followed by 32.7% at BE90 (35 of 107), 18.7% at Novice (20 of 107), 3.7% at BE80(T) (4 of 107), 1.9% at CIC* (2 of 107), 1.9% at Intermediate (2 of 107) and finally 0.9% at CCI** (1 of 107); see figure 3

 

Figure 3: Highest British Eventing (BE) level completed during eventing careers.

Figure 3

30.8% (33 of 107) of horses achieved FP and 11.2% (12 of 107) of horses achieved GP throughout their eventing careers; 24.2% (8 of 33) of horses with FP achieved points at both BE90 and BE100 levels, whilst 45.5% (15 of 33) of achieved points only at BE90 level and 30.3% (10 of 33) achieved points only at BE100 level; see figure 4. 8.3% (1 of 12) of horses with GP achieved points at both Novice and CCI* levels, whereas 91.7% (11 of 12) achieved points only at Novice level; see figure 5.

 

Figure 4: Total Foundation Points (FP) achieved during eventing careers, across all horses.

Figure 4

Figure 5: Total Grading Points (GP) achieved during eventing careers, across all horses.

Figure 5

 

3.2 Testing for correlation with Spearman’s Rho

Testing for normality with KS test showed that all variables were significantly non-parametric (p<0.05). There was no significant correlation (p>0.05) between the highest eventing level completed and the length of racing career (months) or number of racing runs. No significant correlations were found (p>0.05) between racing career length (months) or number of racing runs and the total number of FP, FP at BE90 level, or FP at BE100 level, total GP, GP at Novice level or GP at CCI* achieved.

Weak negative correlations were found between the number of flat races completed and the total FP achieved (n=107, rs=-0.228, p=0.018) and FP achieved at BE100 level (n=107, rs=-0.203, p=0.036). A moderate positive correlation was found between the number of jump runs completed and the total FP achieved in eventing (n=107, rs=0.310, p=0.001) alongside a weak positive correlation between number of jump races completed and FP achieved at BE100 level (n=107, rs=0.203, p=0.036).

No significant correlations were found (p>0.05) between the number of flat or jump races completed and total GP achieved, GP at Novice level or GP at CCI* level. No significant correlations were found (p>0.05) between time between racing and eventing careers (months) and Total FP achieved, FP achieved at BE90 level, total GP achieved, GP achieved at Novice level or GP achieved at CCI* level.

 

3.3 Testing for difference with Kruskall Wallis

No significant difference was found (p=0.115) between the distribution of racing career length (categorised 6 monthly) across the highest BE level completed however the distribution of the number of racing runs (categorised per 6 runs) across the highest BE level completed was significantly different (X22=16.382 n=107 p=0.022), although there was no significant difference between groups (p>0.05) after post-hoc Bonferroni pairwise comparison.

No significant differences were found (p>0.05) between the distribution of racing career length (categorised 6 monthly) across total FP or FP at BE90 level achieved or between the distribution of number of runs (categorised per 6 runs) across total FP achieved. There was a significant difference between the distribution of number of racing runs (categorised per 6 runs) across FP achieved at BE90 level (X22=15.578 n=107 p=0.029) and across FP achieved at BE100 level (X22=14.167 n=107 p=0.048), although there was no significant difference between any of the groups (p>0.05).

The distribution of racing career length (categorised 6 monthly) across FP achieved at BE100 level was significantly different (X22=19.822 n=107 p=0.48), with horses racing for 49-54 months achieving significantly more FP at BE100 level than horses racing for 7-12 months (p=0.040), as shown in table 1.

 

Table 1: Significant findings after testing for difference with Kruskall Wallis and post-hoc Bonferroni correction between racing career length and eventing career success.

Dependent Variable Independent Variable Group specific p value Adjusted p value at post-hoc
Number of FP at BE100 level achieved Racing career length (months) p=0.048 p=0.040

 

There was no significant difference (p>0.05) between the distribution of racing career length (categorised 6 monthly) across the total number of GP achieved or across the GP achieved at Novice level, or across GP achieved at CCI* level. There was also no significant difference (p>0.05) between the distribution of number of racing runs (categorised per 6 runs) across the total number of GP achieved, or across GP achieved at Novice level.

 

The distribution of number of racing runs (categorised per 6 runs) across GP achieved at CCI* level was significantly different (X22=20.400 n=107 p=0.005). Horses racing for 25-30 months achieved significantly more GP at CCI* level than horses racing for £6 months (a) (p<0.001), horses racing for 7-12 months (b) (p=0.001), and horses racing for 13-15 months (c) (p=0.011), as shown in table 2.

 

Table 2: Significant findings after testing for difference with Kruskall Wallis and post-hoc Bonferroni correction between number of racing runs and eventing career success.

Dependent Variable Independent Variable Group specific p value Adjusted p value at post-hoc
Number of GP at CCI* level achieved (a) Number of racing runs p<0.001 p<0.001
Number of GP at CCI* level achieved (b) Number of racing runs p<0.001 p=0.001
Number of GP at CCI* level achieved  (c) Number of racing runs p<0.001 p=0.011

 

There was no significant difference (p>0.05) between the distribution of types of races completed across highest BE level completed, or FP achieved at BE90 level, total GP achieved, GP achieved at Novice level or GP achieved at CCI* level. The distribution of the types of races completed across total FP achieved was significantly different (X22=8.786 n=107 p=0.012); horses competing in jump racing only achieved significantly more FP than those competing in both flat and jump racing (p=0.045). The distribution of the types of races completed across FP at BE100 level was significantly different (X22=7.198 n=107 p=0.027); horses competing in jump racing only achieved significantly more FP at BE100 level than those competing in both flat and jump racing (p=0.034) as seen in table 3.

 

Table 3: Significant findings after testing for difference with Kruskall Wallis and post-hoc Bonferroni correction between type of races completed and eventing career success.

Dependent Variable Independent Variable Group specific p value Adjusted p value at post-hoc
Total number of FP achieved Types of races completed (flat only, jump only, flat and jump) p=0.012 p=0.045
Number of FP achieved at BE100 level Types of races completed (flat only, jump only, flat and jump) p=0.027 p=0.034

 

There was no significant difference (p>0.05) between the distribution of time between racing and eventing careers across total FP achieved, or FP at BE90 level, FP at BE100 level, total GP achieved, GP achieved at Novice level or GP achieved at CCI* level. The distribution of the time between racing and eventing careers across highest BE level completed was significantly different (X22=19.582 n=107 p=0.003); horses with 13-24 months between the racing and eventing careers reached a significantly higher level than those with over 73 months between careers (p=0.024) as seen in table 4.

 

Table 4: Significant findings after testing for difference with Kruskall Wallis and post-hoc Bonferroni correction between the time between racing and eventing careers and eventing career success.

Dependent Variable Independent Variable Group specific p value Adjusted p value at post-hoc
Highest BE level completed Time between racing and eventing careers (months) p=0.003 p=0.024

 

4.0 Discussion

5194 Thoroughbreds were foaled in 2000 (IFHA, 2018), however this project found that only 3869 of these horses made it to the track with 107 competing in eventing following their racing career, suggesting a high wastage rate. Lack of ability was found to be a large contributor to wastage (More, 1999), which could explain the loss of horses prior to racing and eventing careers if potential is not shown during training. Awareness of where these horses end up and reasons behind unsuccessfulness is largely unknown, due to issues in record keeping as highlighted by Collins et al., (2008) when examining the Irish equine industry, learning that only Weatherbys births were truly regulated.

 

4.1 Racing career length

Horses racing for 49-54 months achieved significantly more FP at BE100 level than those racing for 7-12 months (p=0.040) suggesting that horses with longer careers are more inclined to succeed at this level. Benefits to musculoskeletal health have been noted due to early and prolonged exercise in horses (Rogers et al., 2012); creating a robust horse through maintenance of appropriate training may aid the length and potential for success in future careers. Knight and Thomson (2011) found that horses racing as two-year-olds earned significantly more prize money throughout their careers (p<0.001), had significantly longer careers (p<0.001) and completed more races (p<0.001) than horses starting racing older. Knight and Thomson (2011) found that horses beginning training at younger ages, thus enabling longer racing careers to follow, were chosen due to demonstrating high athletic ability and trainability. Such qualities are also sought after in the event horse, highlighting a possible explanation for horses with longer careers achieving significantly more FP at BE100 level.

Vigre et al., (2002) found that horses with the same trainer for more than three months had a reduced risk of lameness, as it takes time for the trainer to create optimal training plans to enhance both performance and musculoskeletal health. Horses that are moved on in less time may not be given opportunity to show their full potential which could be a reason for fewer horses succeeding in eventing, with only 30.8% (33 of 107) achieving FP and 11.2% (12/107) achieving GP and no horses exceeding CCI** level. Sobczynska (2007) found that Thoroughbreds with experienced professional trainers had significantly longer racing careers than those trained by amateurs; professional training may increase positive effects such as musculoskeletal development and therefore speed and stamina, meaning improved knowledge as to why professionals are not commonly training ex-racehorses would be beneficial.

Sobczynska (2007) found horses at smaller yards to more commonly be trained by their owners and not professionals; extrapolating this research to eventing suggests that training could have a large impact upon their success and career longevity, potentially explaining why no significant differences were found other than FP BE100. Caston and Burzette (2018) found 77.5% of horses were reported in eventing training with amateur riders from an online survey, suggesting that ambitions for elite competition and associated training may be reduced, potentially impacting the eventing level reached and GP achieved. Caston and Burzette (2018) respondents were predominantly Thoroughbred horses at 44.6%, echoing thoughts that these horses remain popular within eventing. However, it is important to note that findings could be influenced by response rates in professional riders, as only 3% respondents competed at intermediate or advanced level. Understanding the differences between horse choice in amateur and professionals could improve knowledge on why increased points were only noted in FP BE100

 

4.2 Number of racing runs

Significant differences were found between the distribution of number of racing runs across the FP achieved at BE90 level (p=0.029) and FP achieved at BE100 level (p=0.048). The increase in significance compared to that found across career length could be due to the increased information of how much training and competing the horse undertook during their racing career. The intensity of runs within the horse’s career show the true physiological demands of the career, therefore number of races may be a more representative measure than career length on its own (Castejon-Riber et al., 2017). By assessing the number of runs horses have carried out it was shown that those with increased runs, presented increased success in eventing.

Significantly more GP at CCI* level were achieved by horses running 25-30 races than those running £6 races (p<0.001), 7-12 races (p=0.001) or 13-15 races (p=0.011). It was found that only one horse achieved points at CCI* level meaning the significant differences found may not represent the wider population due to not having enough horses (Etikan et al., 2016). To draw valid conclusions within this area, investigating cohorts of horse with elite eventing results could provide more detailed and representative investigations into the impact of racing career on eventing success, providing better application to industry.

There was a significant difference between the overall distribution of the number of racing runs and the highest BE level completed (p=0.022), however no differences were found between groups. 95.3% of horses’ highest eventing level completed was novice or below, potentially influencing these results as there could be significant differences between number of racing runs compared to higher eventing levels which cannot be fully appreciated with this study population. Levels above novice consist of increased height (≥1.10-1.30m), number (≥28-45) and technicality of jumping efforts, increased speed from £475m/min to ≥520m/min alongside increased technicality required for dressage and show jumping such as the introduction of lateral work and trebles (BE, 2018). Horses capable of competing in these levels require natural ability for the sport, alongside superior musculoskeletal health and training, which can also be impacted by who is training the horse and the time available for development (Sobczynska, 2007), highlighting the importance to understand more on industry practice within training for specific levels of success.

 

4.3 Types of races completed

Negative correlations were found between the number of flat races completed and FP achieved (p=0.018) or FP at BE100 level (p=0.036). Positive correlations were found between the number of jump races completed and total FP achieved (p=0.001) or FP at BE100 level (p=0.036). Horses competing in only jump racing compared to flat and jump achieved significantly more FP (p=0.045) and FP at BE100 level (p=0.034). This suggests that horses training specifically for jump racing could find large benefit throughout the retraining process due to physiological capabilities and coordination, thus indicating that horses completing more jump races show proclivity for higher success rates at levels up to BE100. Horse completing jump racing tend to be older, therefore may not have the time to do detailed enough training to achieve success at higher levels, including those involving GP (Castejon-Riber et al., 2017; Stowe and Kibler, 2016).

Ducro et al., (2009) highlight that elite sport horses require strong conformation to ensure musculoskeletal health and performance, with the large hock and stifle angles to aid jumping, jump race horses are well suited to the biomechanical principles of eventing (Holmström and Philipsson, 1990). Horses with desirable jumping conformation should ideally compete in just jump racing due to natural ability, allowing jump training to progress when retraining for eventing (Ducro et al., 2009). However, if horses compete in flat racing first, it will add extra strain to the distal limbs, increasing injury risk prior to two strenuous jumping careers (Henley et al., 2006), potentially why these horses achieved less FP and FP at BE100 (p<0.05).

Hausberger et al., (2011) found that personality was affected by the type of work the horse was doing, expression became different in the horses, which is important to consider when looking at the number of horses undertaking flat racing compared to jump racing. Horses start flat racing at a younger age, and can train for jump racing as well, although horses that do not suit flat racing may be immediately retried, although a jump career could improve behaviour and performance (Hausberger et al., 2011). As increased jump racing shows a trend of increased success, it is important to explore whether the training involved in jump racing or physiological characteristics are giving horses the advantage.

 

4.4 Time between racing and eventing careers

Negative correlations were found concerning the time between racing and eventing careers and the highest eventing level reached (p<0.001), alongside FP achieved at BE100 level (p=0.029). Alongside this, horses with 13-24months between racing and eventing careers reached a significantly higher eventing level than those with 73months or more (p=0.024), suggesting that horses with shorter time between the racing and eventing careers have increased likelihood of achieving greater levels of eventing success.

Conversely, horses that have small breaks between racing and eventing careers may not have had enough time for conditioning and retraining, meaning they are not physiologically and psychologically prepared for a long and successful eventing career (Lloyd et al., 2008).  Thomson et al., (2014) found that more horses left competitive careers due to unsuitable behaviour than any other reason, highlighting the importance of suitable training and habituation. This could explain why no significant differences were found regarding GP achievement, as horses may require different degrees of training and development to succeed at elite level.

McKenzie, (2017) suggests that short transitions between racing and eventing are common and often successful, as demonstrated with these findings. Training the horse for the high intensity cross country phase should focus more on optimising aerobic capacity and speed which can typically be done over short periods, especially as these horses will already have such qualities from race training (Jang et al., 2017; McKenzie, 2017). McKenzie (2017) explains that lengthier periods of training are required to perfect the discipline and technicality required during phases such as dressage. Horses with shorter periods between racing and eventing careers could be missing this increased precision within their performance, potentially reducing success rates with regards to GP achieved and reaching elite level eventing. It is important to consider that horses within this sample did not exceed levels of CCI**, therefore assessing these correlations and differences with horses at top level such as Advanced/CCI**** would improve application to industry with regards of choosing elite event horses.

Negative correlations between time between racing and eventing careers and highest level achieved or FP at BE100 level could signify that horses with lengthier retraining periods have experienced periods out of work, meaning the horse is not capable of reaching high success levels in eventing due to injury rehabilitation and enduring weakness. Racehorses with superficial digital flexor tendonitis were found to have long periods off work, on average 18 months, however the time to competition fitness could be extensive (Witte et al., 2016), elongating the time between racing and eventing careers. During time out of training, bone mineral density (BMD) has been proven to decrease 0.45% in 12 weeks, highlighting issues with reduction of bone strength and increased injury risk upon return to work, especially in those with lengthy periods out of work before returning to strenuous work. (Yamada et al., 2015; Porr et al., 1998).

 

4.5 Applications to industry

Understanding that horses with longer careers have shown success in eventing can help to improve preventative measures for common injuries and strains seen in both disciplines, to improve career longevity and success alongside reducing wastage. Knowledge on the links between jump racing and eventing success can also aid in horse selection to promote strong conformation and ability, ensuring horses are in a career they can excel in to promote performance, especially at higher levels. The retraining period has been shown to be of importance to eventing success, with shorter periods enabling greater success, potentially due to the horses maintaining training and physiological prowess. Promoting good practice of retraining to ensure physiological benefits from race training are maintained could improve welfare of horses alongside performance. Learning more about why horses are proving successful at lower levels involving FP, but not at higher levels with GP would be useful to improve access for horses to reach the higher levels, improving team GB performance and appealing to wider variety of horse owners.

 

4.6 Limitations

Limitations within this research link to the nature of retrospective data usage, through lack of access or insufficient and incomplete datasets, meaning study design is important to get the most out of the data accessible (Saunders et al., 2012). However, using databases from Weatherbys and national governing bodies reduced the impact of this due to higher standardisation and regulations. This research focused on creating an understanding of baseline patterns within the existing population to enable further exploration into specific areas with prospective or qualitative research. It is not possible to say that horses could not have exceeded the highest eventing level or number of FP and GP achieved during their career as there are many reasons for progression to stop, even where natural talent and good performance is present. Quantitative research based on purely competition records does not enable full comprehension into why horses did not progress further, for example due to reaching peak performance or injury, rider change or financial factors.

Horses could be exported prior to, during, or after racing, which cannot be controlled, leaving gaps in the data as the horses quickly become untraceable due to insufficient regulations and record keeping (Collins et al., 2008). These horses could have competed in other countries in racing and eventing, which could impact the industry-wide perception of retraining racehorses for eventing due to data potentially being incorrect regarding the longevity and success of their competitive careers. It is also possible that ex-racehorses eventing with BE have competed in racing abroad prior to retraining, where full data is not acquirable, potentially impacting data analysis. Horses may transition to unaffiliated rather than BE due to costs, perception of less competitive pressure and more enjoyment-based compared to more intense competition. Accurate and consistent information also cannot be compiled from unaffiliated eventing due to no overarching standardisation in recording and publishing results (Collins et al., 2008).

 

4.7 Future research recommendations

Using prospective research to investigate cohorts from other years could improve knowledge on the careers and success rates post racing retirement. Factors such as the financial crisis, which impacted the UK greatly (Hodson and Mabbett, 2009), could influence the number of horses competing at that time. Therefore, determining why horses are not competing through qualitative research could benefit the industry, alongside investigating a variety of time periods. Thirkell and Hyland (2017) explain that quantitative research prevents greater depth of information being collected, therefore now there is information that factors of the racing career longevity and retraining impact some factors of eventing success, it would be recommended to investigate further with qualitative research, enabling more in-depth conclusions to be drawn.

Horses do not reach the racetrack for varying reasons, for instance poor performance or interruptions to training; some horses are also bred with the intention of other purposes despite the full Thoroughbred bloodlines (Bolwell et al., 2013); it would be interesting to investigate the path of these horses to investigate further where the Thoroughbred event horses start off. There is also little knowledge of what horses do between competition record data, therefore establishing methods of gathering more in-depth data via qualitative research following up with horses throughout the retraining period would be beneficial. Information on the length of time in training for racing following the final race and before the first event would give a better indication on the factors relating to training that impact success in eventing, alongside whether time out of training is truly beneficial or detrimental to the horse’s health and performance.

 

5.0 Conclusion

The research aim was to determine whether the racing career impacts the success of eventing careers post retraining. Overall, horses who competed for a longer time, completed more races, especially jump racing, and had shorter transitions into eventing achieved significantly greater success regarding competition level reached, FP or GP achieved (p<0.05). High wastage rates were found from birth of Thoroughbred foals (n=5194) to racing (n=3869) and finally eventing (n=107), investigating further why those that did not successfully achieve racing or eventing careers could improve knowledge on how to improve training and management strategies to promote good performance in a larger range of horses.

Horses with longer racing careers achieved significantly more FP at BE100 level (p=0.040) suggesting that the physiological conditioning through prolonged training could have lasting benefits to the horse through the eventing career. Underlying conformation, similar demands and training style may contribute to increased jump racing runs resulting in significantly more FP (p=0.045) and FP at BE100 level (p=0.034) being achieved. Horses with shorter periods between racing and eventing careers achieved significantly higher levels in eventing (p=0.003), highlighting the importance of gaining knowledge of horses’ activities throughout their career, to appreciate whether longer periods out of competition equates to injury, therefore potentially limiting future performance. Research to develop this knowledge regarding current success rates of ex-racehorses in eventing, involving qualitative and prospective studies could improve understanding of the interaction between careers further, to promote good welfare, health and performance of Thoroughbred horses.

 

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