Science could help eliminate tiring Endurance horses earlier, say researchers

Science could ultimately deliver an automated risk calculator to identify Endurance horses on a path to elimination much earlier, according to researchers.

The calculator would be driven by algorithms developed through data collected from the FEI database and veterinary cards, on which veterinarians record the condition of horses before each race, and as they progress through each loop.

However, at present, the majority of such cards are filled out by hand, which makes processing the valuable data they contain more laborious.

“It is therefore important that the FEI Veterinary Department consider ways in which these data can be collected in digital format and immediately uploaded to an FEI database,” Euan Bennet and his colleagues at the University of Glasgow report in the Equine Veterinary Journal.

Such an initiative would make much more information available than can currently be gleaned from the FEI’s Endurance database.

They say the results of their latest research, as a whole, provide plenty of evidence to suggest that further collection and routine analysis of veterinary card data could provide significant reward in terms of being able to predict, before and during a ride, which horses are at greater risk of elimination because of gait issues or metabolic problems.

The study team’s work involves the first Endurance research that combines the detailed inspection information recorded on the veterinary cards with the large-scale global FEI database.

Their aim was to find any links between clinical parameters recorded at vet gates during international (CEI) endurance rides and the risk of elimination.

In all, they examined the data on 3213 horse starts worldwide in CEI contests in 2014, ranging from 80km to 160km, involving between three and six loops.

A total of six models, using bespoke code, were applied to the data, leading to the development of a final model.

They found that risk factors such as abnormal gait and high heart rate were repeatedly linked with imminent failure to qualify.

Eliminations after loop 1

Two significant risk factors were identified in relation to first-loop gait eliminations. Increasing rider age and the assessment of the horse’s gait at the pre-ride veterinary inspection were linked with the likelihood of elimination due to gait abnormalities at the end of the first loop.

Compared to horses given a favourable “1” rating in the pre-race check, those rated “2” were more likely to be eliminated because of gait issues at the end of the first loop.

Turning to metabolic eliminations, those with a pre-ride score of “2” or more for their “girth, back and withers soreness score” had a significantly greater chance of a metabolic-related elimination compared to those given a favourable “1” at the pre-ride check.

Eliminations after loop 2

Horses that received a gait rating of “2” at the end of the first loop were at increased odds of a gait-related elimination at the end of loop 2.

Turning to metabolic eliminations, horses with male riders were at increased odds of elimination after loop 2.

Also, horses who initially presented at the veterinary inspection at the end of loop 1 with a heart rate of more than 64 beats a minute were more likely to go out for metabolic reasons after loop 2, compared with those who initially presented with a rate of 64bpm or lower at the inspection after loop 1.

Horses with a mucous membrane score of “2” or above at the veterinary inspection at the end of loop 1 were at increased odds of metabolic elimination at the end of loop 2 compared with those with a mucous membrane score of “1” after loop 1.

Eliminations after loop 3

Horses assessed at the end of loop 2 as having a gait score of “2” were more likely to receive a gait elimination at the end of loop 3 compared with horses with a gait score of “1” at the end of the second loop.

Looking at metabolic eliminations after the third loop, a higher average riding speed in loop 1 was linked to a higher likelihood of vetting out. For each additional km/h of average speed, the likelihood of metabolic elimination increased by 14%.

Horses with a gut sounds score of “2” or above after loop 1 also were at increased odds of elimination after loop 3 compared with those with a gut sounds score of “1”.

Horses whose average speed in loop 2 rose by more than 20% compared with loop 1 were more likely to end loop 3 with a metabolic elimination compared with those whose loop 1 and loop 2 speeds were more consistent, or had slowed in loop 2.

Horses that initially presented at the veterinary inspection at the end of loop 2 with a heart rate of more than 60bpm were also at increased odds of metabolic elimination at the end of loop 3 compared with horses who first presented with a heart rate of 60bpm or less.

Looking at potential dehydration, horses with a skin turgour score of “2” or above at the veterinary inspection after loop 2 were more likely to end the ride with metabolic elimination at the end of the next loop compared with those with a score of “1” at the end of the second loop.

Lameness the biggest risk

Lameness is the most common cause of elimination from Endurance competition, they say. Previous studies, they note, have identified risk factors that include the sex of the horse and rider, the age of the horse, the location of the event, and average riding speeds.

The likelihood of a gait-related disqualification at the end of the first three loops is consistently associated with a horse’s gait score at the previous veterinary inspection, they say.

Consistency of this finding from loop to loop is important in providing greater confidence to veterinary surgeons deciding whether to eliminate a horse for gait issues.

“The knowledge that horses assessed with a gait score of ‘2’ at the end of one loop are more likely to end the ride at the end of the next loop should encourage veterinary surgeons assessing horses as perhaps borderline ‘2’ or ‘3’ on gait score to err on the side of caution and eliminate them at that earlier veterinary inspection, potentially preventing them from sustaining a more serious lameness-related injury later in the ride.”

Alternatively, horses with a gait score of “2” could be required to re-present within a certain time, similar to existing rules around a high heart rate.

Turning to rider age, the analysis showed that older riders were more likely to end a ride with a horse vetting out due to gait issues after loop 1. This risk increases by about 1% for every extra year of age.

The researchers say this association has not been seen in previous research, and may be a finding peculiar to this data.

They say the link between heart rate at the previous veterinary inspection and metabolic eliminations after loops 2 and 3 is important. It suggests that it may be possible to identify horses at greater risk of a metabolic problem well before they are eliminated.

Indeed, these results have been used as evidence to design new regulations for Endurance linked to heart rate at the initial presentation at the veterinary gate that will come into force by July.

From the first vet gate after half way in a ride, or from the third gate onwards (whichever comes first) a horse with an initial heart rate over 68 must undergo a further vet check before being allowed to continue.

The study team says the clinical assessment of mucous membranes, gut sounds, skin turgour, and girth, back, and withers soreness all form part of the veterinary inspection, with issues indicating elimination later in the ride.

Bennet and his colleagues say the study is, by its nature, a pilot. “The results provide strong motivation to design data collection protocols to carry out a larger scale study.

“It is important that this, alongside all other findings in this study, are replicated in a larger-scale analyses once an easier system to collect veterinary inspection data from all FEI endurance rides is established.”

They say their findings show the true potential value of collection and analysis of veterinary gate data by the FEI for all Endurance rides in the future.

“An initial effort to establish a mechanism by which these data can be more readily collected from all FEI Endurance rides could provide, within one year, approximately four times as many veterinary cards as were analysed in this study.

“This analysis could then be extended to include individual horse and rider histories to develop risk profiles for each rider/horse combination, that evolve in real-time over the course of an Endurance competition, to reflect the findings of clinical examinations recorded at each veterinary inspection.”

The next step would be to develop algorithms for use in an automated risk calculator available to endurance vets, which will help them make evidence-based decisions about which horses to eliminate earlier in rides before more serious issues arise.

Bennet told Horsetalk: “With the motivation provided by these results we have already begun a larger follow-up study, starting by collecting vet cards from FEI international rides.

“We aim to collect at least 20,000 vet cards over the next 18 months and analysis of that many records should provide a much more solid understanding of this area of work on which a future risk calculator could be based.”

The full study team comprised Bennet, Megan Hayes, Laura Friend and Tim Parkin.

The association between clinical parameters recorded at vet gates during Fédération Equestre Internationale (FEI) endurance rides and the imminent risk of elimination.
Bennet E.D., Hayes M.E., Friend L., Parkin T.D.H.
Equine Vet J. 2020 Mar 27. doi: 10.1111/evj.13264.

The abstract of the study can be read here.