The Influence of Horse Gender on Eventing Competition Performance

Comparative Exercise Physiology 5(2); 67–72 doi:10.1017/S1478061508017039

The inﬂuence of horse gender on eventing competition performance

TC Whitaker*, O Olusola and L Redwin Centre for Equine and Animal Science, Writtle College, Chelmsford, Essex CM1 3RR, UK * Corresponding author: [email protected]

Submitted 7 February 2008: Accepted 27 May 2008 Research Paper

Abstract The study undertook comparative analysis of horse gender and eventing performance. Limited previous research has investigated the impact horse gender may have on performance. However, many competitors have a prefer- ence for one gender over another (normally geldings). The study sampled ﬁve levels of the sport (intro, pre-novice, novice, intermediate and advanced) and investigated dependent variable penalty scores within the dressage, show jumping and cross-country phases; additionally, ﬁnal penalty score, rank in competition and lifetime score were analysed. Results indicated the effect of gender to be limited. Issues relating to sample size, data structure and scoring mechanisms are discussed further.

Keywords: eventing; gender; performance

Introduction differences have yet been reported between mares and geldings4. Currently, our understanding of differences in equine Harkins et al.5 found gender differences in the per- competition performance relating to horses’ gender formance of Thoroughbred racehorses; males showed is limited. Differences in performance have been no significant difference in performance between observed within racehorse and trotter populations1–3. solo training gallops and competitive runs, but The relationship, however, is not simplistic. If these females ran significantly more slow during competitive observed differences are considered to be significant runs. However, no physiological or psychological and occurring in a systematic manner, their impli- reasoning for these results was given other than cations need careful thought. Particular consideration impaired run times during competition in females would need to be given to their effect on potential may be stress induced. Associations between gender selection decisions whether they are being made in a and performance relating to heart rates during sub- sporting or breeding context. maximal exercise in Thoroughbred racehorses have Physical and psychological differences between the been suggested5–7. A significant difference was found genders need to be analysed in order to understand in the heart rates between male and female horses not only which gender may be superior but also when cantering a 500 m circular track at submaximal why. Limited literature has been published on the levels, which suggests that the aerobic capacity of physiological differences between genders in horses, males may be higher than females6. yet sexual dimorphism occurs in horses. Males tend There have been few reports on the analysis of to be taller and heavier than females and horsemen competition performance between mares, geldings and often feel that stallions are more muscular than geld- stallions at different levels of competition and between ings, although body composition is rarely measured disciplines. Whitaker et al.8 investigated scoring in horses. Physiological differences in muscle fibre patterns in eventing competition at six pre-novice proportions between sexes would suggest that events. The results showed very little variation in final mares have less power and stamina with lower pro- penalty scores (0.8 penalties) between mares and portions of type IIA muscle fibres, and therefore fati- geldings. However, a significant variation between gue more quickly than stallions4. However, no such mares and stallions (with stallions scoring on average qCambridge University Press 2008 68 TC Whitaker et al. 12.2 points lower) and between geldings and stallions competing at the novice, intermediate and advanced (with stallions scoring on average 11.4 points lower) levels. They are based on the level of competition, final was observed. Marsalek et al.9 studied show jumping rank in competition and the number of total competitors competition and suggested that stallions were reaching within competition. All data were collated from the a higher percentage of clear jumping rounds than British Eventing web-sourced database11 and details of both mares and geldings and that mares refused jumps horse gender were collated from event programmes. more frequently than geldings and stallions. Whitaker Data were found to be skewed at all levels for SJJ, SJT, et al.10 indicated that within the progeny groups of elite XCJ, XCT and total penalty scores; therefore, all data eventing sires, male performance was superior when were transformed using the Bartlett’s (log x þ 1)12 measured by points won over the animal’s whole com- approach. This reduced the skewness of the data to a petitive career. These pieces of research would suggest suitable level before appropriated parametric statistical that males generally and stallions specifically have a analysis was undertaken. superior performance than mares. However, Whitaker Descriptive statistics and measures of dispersion et al.8 only looked at one level of competition, while Mar- defined by the independent variables were returned salek et al.’s9 work was focused on international show for all dependent variables at the various levels of com- jumping events; Whitaker et al.10 reviewed only progeny petition. Differences between gender, mean rank in of elite stallions and only lifetime performance. competition and mean penalty scores in D, SJJ, SJT, This study aimed to investigate the effect of horse XCJ XCT and total penalty score were assessed using gender on competition performance within eventing. independent t-tests13 for all levels of competition. Stal- The stated hypothesis, horses’ gender has no signifi- lions were found competing within the pre-novice, cant effect on eventing competition performance, novice and intermediate levels of competition. was tested. A sample of all levels of affiliated national However, the small numbers made comparative analysis level competition run within the UK is used as the stu- impossible; for the pre-novice and intermediate levels, died population. Performance measures used include only one and two stallions were present, respectively. phased and final competition scores as well as final Within the novice level, six stallions were present; 13 rank in competition. however, a Fmax-test indicated inequality of variances (P . 0.05) when stallions were included within the Materials and methods analysis. Comparative analyses to establish whether significant differences were present for final rank Eventing (also known as horse trials) is an equestrian in competition (by level) were undertaken via a event that combines three disciplines: dressage, show Mann–Whitney U-test13. jumping and cross-country into one competition11.The All horses that failed to complete a competition penalty scores from each of the three phases are com- were excluded from the data analysis. Such horses bined to produce an overall total penalty score (cumulat- present incomplete performance records and make ive basis). The competitor with the overall lowest analysis much more complicated. Non-completion of penalty score is ranked first in competition. The five competition is a complex and multi-factorial issue. main levels of affiliated national level competitions are However, evidence from other studies (in eventing)8 intro (Intro), pre-novice (PN), novice (N), intermediate would suggest that such non-completers can be (Int) and advanced (Adv), with competitions becoming described as missing at random. Therefore, the exclu- progressively more difficult and complex. Details of sion from the analysis is an acceptable approach. the nature and structure of British Eventing disciplines have been described previously8. A total of 185 events Results were run in 2006 in the United Kingdom. The dataset comprised 1156 horses (1.7% of all Data structure competition entries) and the data were analysed by the Of the 1156 horses, 170 completed intro level, 306 com- level of competition. Competition performance records pleted pre-novice level, 372 completed novice level, were described as dependant variables; gender (mare, 215 completed intermediate level and 91 completed gelding and stallion) was defined as the independent advanced level. The percentage of mares performing is variable. Dependent variables used included dressage seen to fall as level of competition rises, 31.2% at intro penalty scores (D), show jumping jumping penalty level to 9.9% at advanced level (Fig. 1). The number of scores (SJJ), show jumping time penalty scores (SJT), animals with no gender reported is observed to be com- cross-country jumping penalty scores (XCJ), cross- paratively consistent throughout the levels (minimum country time penalty scores (XCT) and final penalty 4.3% advanced level, maximum 6.5% novice level). score. Final rank in competition and lifetime points Within the sample studied stallions are only observed score were collected as additional dependent variables. to compete at the pre-novice, novice and intermediate Lifetime point scores are only awarded to those horses levels and the numbers are small (n ¼ 1 to 6). Horse gender on competition performance 69

FIG.1 Gender (numbers) of competing event horses by level of competition

Phase and final penalty score Novice Table 1 returns mean final penalty scores for each No significant differences were observed within any phase of competition as well as overall final penalty phases of competition or for final penalty score. Trends score by gender and level. were, however, observed for SJJ (t ¼ 1.784, df ¼ 148, P ¼ 0.077); unequal variances assumed (F ¼ 6.263, Intro P , 0.05) with geldings scoring 0.9 penalties lower; No significant differences were observed within any XCT (t ¼ 1.947, df ¼ 340, P ¼ 0.052) with geldings phases of competition or for final penalty score. Geld- scoring 2.2 penalties lower; final penalty score ings did, however, have a final penalty score of 3.4 (t ¼ 1.743, df ¼ 340, P ¼ 0.082), with geldings scoring points lower than mares. A relationship that could be 4.6 penalties lower. described as towards a trend (P ¼ 0.071) was reported for SJT; this amounted to mares scoring 0.1 penalties lower than geldings. Intermediate No significant differences were observed within D, SJT, Pre-novice XCJ and XCT phases of competition or for final penalty No significant differences were observed within the score. Mares did, however, have a final penalty score of phases of competition D, SJJ, XCT, XCJ and final pen- 3.4 points lower than geldings. Trends were, however, alty score. Geldings did, however, have a final penalty observed for D (t ¼ 1.729, df ¼ 203, P ¼ 0.085), score of 3.4 points lower than mares. Mares scored 0.4 with geldings scoring 1.8 penalties lower. A difference penalties lower than geldings for SJT (t ¼ 22.053, (t ¼ 22.550, df ¼ 203, P , 0.05) was reported within df ¼ 231, P , 0.05); unequal variances assumed the SJJ phase of competition, mares scoring 2.0 penal- (F ¼ 11.061, P , 0.001). ties lower than geldings.

Table 1 Mean-phased and ﬁnal penalty scores for gender by competitive level

Level Gender D SJJ SJT XCJ XCT Total Intro Mare 38.2 (0.87) 3.1 (0.50) 0.5 (0.28) 13.3 (3.09) 6.8 (1.15) 62.0 (4.16) Gelding 38.0 (0.50) 4.7 (0.48) 0.6 (0.26) 8.3 (1.47) 7.0 (0.99) 58.6 (2.41) PN Mare 38.3 (0.78) 5.0 (0.60) 0.2 (0.11) 11.8 (2.62) 4.7 (0.86) 60.1 (3.35) Gelding 37.8 (0.42) 4.3 (0.32) 0.6 (0.16) 8.7 (1.26) 5.4 (0.60) 56.7 (1.19) N Mare 36.6 (0.56) 4.7 (0.52) 0.7 (0.35) 5.0 (1.49) 14.0 (1.16) 61.0 (2.79) Gelding 35.8 (0.31) 3.8 (0.27) 0.2 (0.07) 4.9 (0.80) 11.8 (0.58) 56.4 (1.38) Stallion 31.9 (2.64) 0.7 (0.67) 0 0 3.5 (1.91) 36.1 (3.77) Int Mare 38.9 (0.95) 4.0 (0.85) 0.9 (0.75) 7.1 (3.51) 17.4 (2.06) 68.2 (5.30) Gelding 37.1 (0.44) 6.0 (0.45) 0.8 (0.29) 8.3 (1.22) 19.3 (1.08) 71.6 (2.40) Adv Mare 37.7 (2.84) 6.2 (1.51) 0.1 (0.11) 2.2 (2.22) 19.2 (2.55) 63.7 (4.34) Gelding 38.1 (0.53) 5.5 (0.71) 1.4 (0.46) 6.7 (1.53) 22.5 (1.14) 73.1 (2.94)

Standard error stated within parentheses. 70 TC Whitaker et al. Advanced No significant differences were observed within any phases of competition or for final penalty score. Mares did, however, have a mean final penalty score of 9.4 points lower than geldings.

Final rank in competition and lifetime points Figure 2 shows comparison of median rank in competition by gender. No significant differences were observed. It can, however, be noted that at the intro and pre-novice levels mares are ranked slightly higher (worse), while at the higher levels intermediate and at the advanced level they are ranked slightly FIG.3 Mean lifetime points awarded in competition by gender for novice, intermediate and advanced levels of eventing competition lower (better) than geldings. The analysis of mean lifetime points awarded (Fig. 3) showed no significant differences between mares and geldings when ana- 4.7 and 3.9 penalties lower than mares and geldings, lysed by level (novice, intermediate or advanced). It respectively, 4.0 and 3.1 lower for SJJ, 0.7 and 0.2 is, however, noted that at advanced level geldings lower for SJT, 5.0 and 4.9 lower for XCJ, 10.5 and accrued on average more than twice the number of 8.3 lower for XCT, and 24.9 and 20.3 lower for final points than mares. Median points awarded for all penalty score. three levels (novice, intermediate and advanced) were zero for all genders and levels. When the novice, intermediate and advanced levels were con- Discussion sidered together as a whole, geldings’ mean points score was noted at 1.85 points, while mares’ score This study shows that within the population studied was noted at 1.28 points; t ¼ 22.239, df ¼ 321, there appears to be very little difference when com- P , 0.05; unequal variances assumed (F ¼ 5.454, paring the performances measured by penalty score P , 0.05). (phased and final), final rank in competition or lifetime points between mares and geldings. Previously, Stallions difference in performance has been observed bet- Due to the very low number of stallions within the ween female and male horses1–3. It is, however, dataset, appropriate comparative statistical analysis likely that the relationship between performance and was not possible. However, within the novice level equine gender is not necessarily easy to understand of competition, six stallions competed, and it is inter- or one-dimensional. Differences between human esting to note their performance. Overall, stallions male and female performances in sporting competition were ranked much lower in competition, with a have been noted; statistically, the male performs better median rank of 1.5. Median rank for both mares and than the female (Patterson et al., 2005)14. However, geldings was 15. Their median lifetime point’s accumu- the exact nature of this relationship is more difficult lation was 5.5 compared with 0 for both mares and to quantify. It has been suggested that these gender geldings. Within the dressage phase, stallions scored differences may disappear when the fatigue/endurance of a sport increases (Coast et al., 2004)15. The percentage of mares performing is observed to steadily drop as the level of competition rises: 31.2% Intro, 25.2% PN, 22.8% N, 18.6% Int and 9.9% Adv. This pattern is similar to that reported previously at various levels of the sport9,10. However, the com- monly held assertion that geldings are better animals for competition in terms of performance is not sup- ported. The study indicates that there are very few significant differences in performance between the two genders. Where differences are apparent, the level of these differences is comparatively marginal. When considering final rank in competition, it is interesting to note (although not found to be significant) that it FIG.2Median final rank in competition by gender for each level is in fact mares that have the lower median rank at of eventing competition the highest level of competition. Horse gender on competition performance 71 Within the studied population, the small number likely to select potentially better horses at a younger of stallions competing (n ¼ 9) made comparative age. They also stated that, at the highest levels of com- work impossible. At novice level of competition, the petition, rider effect may be minimal. Furthermore, observed stallions consistently outperform both they concluded that, at the lower levels of compe- mares and geldings throughout all phases of competition, skilled riders are exerting a more influential tition and in overall final rank in competition. Stallions effect on potential performances than less skilled are expected to be the future sires of the next eventing riders. Significant difference has been observed generation; it may, therefore, be suspected that their within the dressage phase of competition at both the performance may be superior. However, it is of con- novice and pre-novice levels8,24. Additional work has cern that so few stallions are undergoing performance highlighted differences at advanced level within the testing within a competition environment. It should cross-country phase25. also be considered that, because of the relatively Consideration of gender in relation to behaviour is small number of mares competing at intermediate worthy of reflection. Reduction in desired level of per- and advanced levels, establishing comparative differ- formance has been demonstrated within equines as a ences becomes difficult. It is noted that at intermediate direct result of behaviour. Various authors26–28 have level mares’ final penalty score was 3.32 points lower highlighted the differences in manifestation of sexual than geldings’; while at advanced level, it was 8.26 behaviour and how this might have a negative impact points lower. Neither of these differences, however, on performance. The need and methodologies that proved to be significant. Further consideration needs may be adopted to reduce these behaviours have been to be given to the possibility that mares may retire ear- discussed and reviewed elsewhere26–28. The use of lier than geldings or have an interrupted performance training and management as a tool for controlling beha- career to undertake breeding duties. Within this study, viour may be more effective in the male horse (stallion it was not possible to integrate data to analyse this or gelding). Visuo-spatial ability in males is superior potential effect; however, further study of this would to that of females in most species, including horses29. be worthy of consideration. In conclusion, there appears to be very little differ- It is interesting to consider that the median lifetime ence in the performance of mares and geldings at all points won by either gender at all levels of competition levels of eventing, despite a preconception that were zero. This effectively means that a large pro- geldings are more suitable competition animals. It is portion of the population is recording no lifetime win- recommended that future study involves a consider- nings from competition. The problems of non-linearity ably larger studied population. The non-significant in scoring systems and the consequential hyper- lower final penalty scores of mares at the higher geometric distributions have been described else- levels are particularly worthy of consideration. where16–18. However, comparative assessment (using Additional study of the effect of potential confounding median scores) between mares and geldings using life- factors, such as horses’ age or rider’s skill, need to be time winnings is therefore impossible. The situation is considered within any further work. It is impossible to confused further if arithmetic means are used at the undertake comparative analysis of stallions; however, novice and intermediate levels, when no meaningful where they do perform their performance is consider- difference is observed (0.71 vs. 1.14 at novice, 2.4 vs. ably better than both that of mares and geldings. The 2.5 at intermediate). At advanced level, comparison of use of lifetime scores as a measure of performance mean scores shows that geldings collect over twice as results in a large proportion of horses being awarded many points (5.2) as mares (2.2), this is despite the no score. 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