Racehorses’ performance predicted by gut bacteria when they are foals

Racehorses’ future performance can be predicted by the bacteria in their gut when they are foals.

Lineage, size, and training are all part of the recipe when it comes to making a thoroughbred into a proven winner, and now scientists are turning to the gut microbiome in search for another competitive edge.

Faecal samples of 52 foals from five stud farms across the country were sampled within the first four weeks of their life to assess the range and abundance of bacterial species in their gut.

Data from their races over the next three years found that equines born with a greater diversity of bacterial species in their gut were more likely to achieve a higher ranking, win more races and earn more money.

“Foals with the highest levels of gut bacterial diversity at four weeks old went to be ranked four times higher for prize money earnings than foals with the lowest levels of gut bacterial diversity,” Prof Chris Proudman, the study lead author and professor of Veterinary Clinical Science at the University of Surrey, told The Telegraph.

He adds that the diversity of bacteria in a horse’s gut could be used in the future as a predictor of which animals will achieve the greatest athletic success.

Unclear how microbiome boosts performance

Data in the study also showed that having more of two types of bacteria specifically — Anaeroplasmataceae and Bacillaceae — is associated with better performance on the racetrack.

The authors of the paper say this is the first time scientists have shown that gut microbiome can have a significant impact on racehorse performance and suggest it could soon become just as pivotal to horse racing as diet.

However, it remains unclear exactly how the gut microbiome diversity boosts performance and what biological processes are going on.

“One possibility is that this effect is linked to immunological competence,” Prof Proudman suggests.

“We also demonstrated a health advantage in having high gut bacterial diversity at four weeks old, this health effect is likely to be mediated by immunological factors.

“A further possibility is that there are currently unknown interactions between gut bacteria in early life and the development of muscles, including heart muscle, and bones. These possibilities need to be investigated in future mechanistic studies.”

Newborns with antibiotics perform worse

The scientists also found that foals given antibiotics as a newborn performed worse in races and also had links to health conditions in later life.

“The average ranking based on race earnings was twice as high in untreated foals compared to those that received antibiotics in the first month of life,” Prof Proudman told The Telegraph.

The study is the latest publication from an ongoing series of work at the University of Surrey looking at the role and influence of the gut microbiome on horses, and the next step is looking at the potential benefit of probiotics.

Prof Roberto La Ragione, the co-investigator from the University of Surrey, said: “Our study demonstrates that treatment with antibiotics can disrupt the healthy gut microbiome with long-term impacts on health and performance.

“The next part of our study will examine how we can minimise disruption of gut bacteria when antibiotics have to be used to treat infections.”

Dr Kirsten Rausing, chairman of the International Thoroughbred Breeders Federation and, through her Alborada Trust, the study sponsor, commented: “This ground-breaking study has identified the importance of gut health in our very young foals.

“As breeders, if we can get this right, we will produce foals that will be healthier, and that will grow into more successful racehorses.”

The study is published in Scientific Reports.