The age of the parents can be a key factor in helping Thoroughbreds to be first in line

In a sport where the winner can be determined by the highest finish, a parent’s age can be a determining factor in who will come out on top in a jump, a new study has found.

Experts from the University of Exeter have shown that the speed of thoroughbred horses decreases as the age of the parents at conception increases. The research team analyzed more than 900,000 horse performances from more than 100,000 racehorses from racecourses across the UK.

They found that the age of both the horses’ mothers and fathers played a significant role in the overall speed of the racehorses.

The researchers believe that the study could play a key role not only in optimizing the breeding of racehorses, but also offers further evidence that the age of the parents can influence offspring characteristics.

The study is published in the journal Royal Society for Open Science on Wednesday, October 5, 2022

Dr Patrick Sharman, PhD (visiting) from the Center for Ecology and Conservation at the University of Exeter’s Penrhyn Campus in Cornwall, said: “The fact that sire age affects the speed of racehorses should be of interest to the horse racing industry.

“More generally, this adds to the growing body of evidence that parental ‘condition’ at conception influences offspring phenotype. This will have ramifications far beyond racehorses and the horse racing industry.”

The effect that parental age can have on the characteristics of their offspring has been studied in a number of species in recent years. However, this is the first in-depth study that has attempted to assess the effect of maternal and paternal age on the speed of Thoroughbred horses.

The research analyzed almost 25 years of race results data, from 1996 to 2019, from meetings across the UK. Their data included the offspring of 41,107 mothers and 2,887 fathers. They found a “significant effect” of mother’s age per speed, with each additional year of age at conception decreasing the speed of the offspring by 0.017 yards per second.

While this may sound modest, it actually translates into a predicted difference of about one second over the course of a one-mile race between, say, a five-year-old mother and a 15-year-old mother. Interestingly, sire age also showed a decrease of 0.011 yards per second with each increase in stallion age – a key finding as thoroughbred stallions do not actively participate in parental care.

Dr Sharman added: ‘It is perhaps not surprising that the rate of offspring declines with maternal age. After all, it is the dams who take care of the foal first in utero and then until about 6 months of age.

“However, what I find fascinating is that increasing sire age also causes a significant decrease in speed in racehorses. Thoroughbred stallions play no role in raising the foal, so what is behind this decrease in speed?”

The team says further research is now needed to determine the mechanisms underlying this phenomenon.

Evidence for the effect of maternal and paternal age on speed in thoroughbred racehorses published by Art Royal Society for Open Science.