AR-News: Equine welfare: Risk of horses falling in the Grand National

[AAVS]

Equine welfare: Risk of horses falling in the Grand National
Nature 428, 385 - 386 (25 March 2004); doi:10.1038/428385a
 
Analysis of past tumbles in this gruelling steeplechase points to ways of
making it safer. 
As in other competitive sports, the famous Grand National steeplechase,
which is held at Aintree in the United Kingdom and is watched by 600 million
people worldwide1, sometimes results in injury. By analysing data from the
past 15 Grand National races (consisting of 560 starts by horses), we are
able to identify several factors that are significantly associated with
failure to complete the race: no previous experience of the course and its
unique obstacles, unfavourable ground conditions (too soft or too hard), a
large number of runners, and the length of the odds ('starting price'). We
also find that there is an increased risk of falling at the first fence and
at the jump known as Becher's Brook, which has a ditch on the landing side.
Our findings indicate ways in which the Grand National could be made safer
for horses and illustrate how epidemiological analysis might contribute to
preventing injury in competitive sport.
The race comprises 30 obstacles over a distance of 4.5 miles (7.2 km) (Fig.
1). We used multivariable models to identify the variables associated with
non-completion and with falling (see supplementary information).
Figure 1 Layout of the course of the Grand National.   Full legend

The probability of remaining in the race (Fig. 2a) shows a marked decline at
fence 1, followed by a steady decline throughout the rest of the race.
Non-completion is further subdivided into different types (Fig. 2b), and
demonstrates an increased rate of falling and of horses being 'brought down'
early in the race by interference from another falling horse, followed by a
higher rate of refusals and horses 'pulling up' (jockey-initiated withdrawal
from the race).
Figure 2 Patterns of non-completion of the Grand National during the past 15
races.   Full legend

Compared with other plain fences (no ditch), the first fence is almost seven
times more likely to result in a fall (odds ratio, 6.8; 95% confidence
interval, 4.6, 10.0). Becher's Brook (odds ratio, 4.7; 95% CI, 3.2, 7.1),
open-ditch fences (odds ratio, 2.4; 95% CI, 1.6, 3.6), Canal Turn (odds
ratio, 2.1; 95% CI, 1.2, 3.6) and The Chair (odds ratio, 2.3; 95% CI, 1.1,
4.6) all confer a significantly increased risk of falling.
Ground classified as 'soft' or 'heavy' resulted in a significantly higher
rate of non-completion (hazard ratio, 2.05; 95% CI, 1.32, 3.17) compared
with all other types. The model predicts that only 18% of runners will
complete when the 'going' is soft or heavy (Fig. 2c). Horses that had never
raced on the course were twice as likely not to complete it (hazard ratio,
2.0; 95% CI, 1.52, 2.63) as horses that had had previous experience without
a fall (Fig. 2d); this relationship remained after adjusting for age. The
number of runners in the race was associated with non-completion (hazard
ratio, 1.09 per runner; 95% CI, 1.01, 1.13), as was the 'starting-price
multiplier' (the inverse of starting price; hazard ratio, 1.004; 95% CI,
1.002, 1.006) — the longer the odds, the greater the probability of
non-completion.
Falling or unseating of the jockey as a result of a jumping error is the
outcome most likely to result in injury2-4. Horses with no previous
experience on the course were at increased risk of falling and of losing
their rider (hazard ratio, 2.6; 95% CI, 1.80, 3.87). Good-to-soft ground was
associated with a significantly decreased risk of falling relative to good
ground (hazard ratio, 0.41; 95% CI, 0.21, 0.78). The number of runners in
the race (hazard ratio, 1.08; 95% CI, 1.01, 1.17) and the starting-price
multiplier (hazard ratio, 1.003; 95% CI, 1.001, 1.005) were also
significantly associated with a risk of falling.
Our results indicate that increasing the schooling of horses over fences of
the type used for the Grand National, or in qualifying races over the Grand
National course, and providing good-to-soft ground would improve completion
figures and decrease the risk of horses falling during the race. The greater
risk of falling at the first fence indicates that interventions involving
this obstacle could have a big impact on the number of horses that complete
the race.

These findings also illustrate the value of using epidemiological methods to
identify risk factors for injury in competitive sport and should inform the
efforts of the racing industry to safeguard equine welfare in the Grand
National steeplechase.
Supplementary information accompanies this paper.
CHRISTOPHER PROUDMAN, GINA PINCHBECK, PETER CLEGG & NIGEL FRENCH
Epidemiology Group, Faculty of Veterinary Science, University of Liverpool,
Leahurst, Neston, Wirral CH64 7TE, UK

c.j.proudman at liverpool.ac.uk

References 1.http://www.aintree.co.uk
2.McKee, S. L. Eq. Vet. Educ. 7, 202–204 (1995).
3.Tuner, M., McCrory, P. & Halley, W. Br. J. Sports Med. 36, 430–409 (2002).
4.Williams, R. B., Harkins, L. S., Hammond, C. J. & Wood, J. L. N. Eq. Vet.
J. 33, 478–486 (2001). | ISI | ChemPort |


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