Trainers talk about how racehorses get excited on race-day at the prospect of a hit-out on the track, and a study in Hungary largely confirms this.
Researchers found a clear differences in a group of eight Standardbred racehorses between their build-up to a training run and their build-up to an actual race.
Their study findings, reported in the open-access peer-reviewed journal PLOS ONE, were based on a series of measurements taken of plasma cortisol concentrations and sympathetic tone-related heart-rate variability.
The hormone cortisol is a versatile chemical regulator in every species. It is the primary hormone responsible for the stress response to physical and psychological challenges.
Researchers Zsófia Bohák, Andrea Harnos, Kinga Joó, Ottó Szenci and Levente Kovács described their experiment involving eight Standardbred stallions, aged 3 to 4 years, who lived in stables near the racetrack at Kincsem Park in Hungary.
Trotting races are organized every Wednesday and Saturday at the park.
Daily routines and feeding do not differ between training and race days, they said.
However, on race days, the horses are exposed to the atmosphere of race day – they can hear the noise of transporters and the loudspeaker.
The preparation of the horses occurred in the same way on both days of the experiment (one was a training day, the other a race day), but the driver wore more colorful clothes on the day of race.
Horses were kept in the same stable and trained by the same driver and horses were not transported during the experiment.
The horses covered 8000 to 9000 metres a week in training, and raced over 2300 metres.
In all cases, blood was taken at various stages for cortisol analysis – a baseline test, five minutes before warming up, after warming up, immediately after the intensive exercise, and after a 30-minute recovery.
Equipment was fitted to allow the heart-rate to be monitored before, during and after exercise.
The results, they said, showed an anticipatory response in racehorses before trotting races, reflected in the cortisol levels recorded.
However, vagal tone-related heart-rate variability did not confirm this phenomenon.
Also, there was a lack of significant cortisol increase during the race, but this might have resulted from the excessively high basal values.
Discussing their findings, the researchers said it cannot be excluded that the effects seen in the horses may have not only have affected the experimental animals, but all the horses kept in these stables, even when they had not been entered in a race.
“The elevated pre-exercise sympathetic tone before race may reflect the totality of many impacts, like the environment, the forthcoming exercise and the associated competition stress.”
To study performance-related increases in cortisol levels it would be important to exclude the effects of race atmosphere, they said.
Bohák Z, Harnos A, Joó K, Szenci O, Kovács L (2018) Anticipatory response before competition in Standardbred racehorses. PLoS ONE 13(8): e0201691. https://doi.org/10.1371/journal.pone.0201691