Groundbreaking Study – Why the First 28 Days Can Shape a Racehorse’s Life
New research has revealed something powerful for the Thoroughbred industry and putting the odds in your favour:
A foal’s gut health in the first month of life can strongly predict how healthy and successful that horse will be years later!
This study followed 52 Thoroughbred foals from birth to three years old. It showed that gut bacteria at just 28 days old were linked to future respiratory disease, gut problems, soft-tissue injuries, and even racing performance.
Below is a clear simple breakdown of this journal article published in 2024 of the biggest findings and what it means for every performance horse industry.
Researchers tracked each racehorse’s health and performance for up to 156 weeks
Health data:
- Every week, they recorded any vet issues:
orthopaedic, soft tissue, respiratory, or gut problems. - Most horses were monitored for an average of 127 weeks.
- For consistency, all data was capped at 156 weeks.
Race performance:
Prize money earned – They used each horse’s official racing name to pull results from a public database. After every race, they recorded: Finishing position, Official Rating (OR) – a score that goes up as performance improves. They also tracked lifetime stats up to Dec 2021: Total starts, Wins Placings.
(A) Lower gut microbiome diversity at 4 weeks.
(B) Worse race performance later (lower Official Ratings).
(A) Lower lifetime earnings.
Antibiotics in the First Month: A Hidden Risk
The study showed a clear pattern:
Foals given antibiotics in the first month of life had:
- Higher risk of respiratory disease later in life
- Worse overall health
- Lower racing performance
This strongly suggests that disrupting the microbiome early can negatively shape the horse’s future.
Another important point:
None of the foals given antibiotics in the first month actually had respiratory disease at the time. This means the antibiotics, not the sickness, were the likely cause of the later health and performance problems.
This finding supports what human research already tells us:
Early antibiotic exposure can shift gut bacteria in a way that affects immunity and performance long-term.
Gut Diversity At One Month Can Predict Race Performance
This is the breakthrough discovery from this study.
Foals with more diverse microbiomes at 1 month old:
- Improved racing performance
- Earned more prize money
- Had higher official ratings
This connects with a new scientific field called sportomics, studying how an athlete’s body and microbiome interact.
Most human and horse studies have focused on how the microbiome changes during training or competition.
This study is the first to show that microbiome before training even begins shapes future athletic ability. In simple terms:
A healthy gut early in life builds a stronger athlete.
The First Month Shapes the Next Three Years
This study delivers one major message for studs and breeders:
What happens in a foal’s gut in the first 28 days can shape the horse’s entire future.
Foals with diverse, well-developed gut microbiomes early in life:
- stays healthier
- develops stronger immune systems
- suffers fewer respiratory and soft-tissue problems
- performs better on the racetrack
Avoiding early antibiotics and supporting natural microbial exposure appear to be two of the most powerful tools studs can use.
For the first time, science shows that gut health in early life helps build the athlete long before training begins – not just in horses, but possibly across all species, including humans.
Why These Findings Matter for Studs, Trainers and Horse Owners
This study gives breeders and studs a powerful roadmap:
What helps a foal’s microbiome early on?
- A healthy mare gut microbiome
- Exposure to natural pasture microbes
- Low-stress environments
- Low use of disinfectants
- Avoiding unnecessary antibiotics
- Some ability to mimic natural behaviours (grazing, exploring, socialising)
What can harm it?
- Early antibiotics
- Excess sanitisation
- Poor-quality or contaminated feed
- Stress from handling or environmental change
- A mare with a compromised gut microbiome
- Lack of exposure to natural microbes
Because foals inherit many of their first microbes from the mare and environment, mare health is as important as foal health.
How To Promote Microbial Diversity Through Nutrition
The CEN Nutrition feed program for mares and foals provides a clean, fresh fibre sources that boosts microbial diversity, that works alongside your pasture or hay.
Our feed delivers high-quality protein, low sugar and starch with zero rancid oils, fillers, or contamination, just pure fresh ingredients for your horse’s gut health. For a Free Diet Analysis please book at the CEN Nutrition website – https://cennutrition.com.au/horses/free-diet-analysis/
Written By Bryan Meggitt (BMedSc. PGCrtMedSc.)
Blood Scientist and Co-founder of CEN Horse Nutrition
References:
- Leng, J., Moller-Levet, C., Mansergh, R.I. et al. Early-life gut bacterial community structure predicts disease risk and athletic performance in horses bred for racing. Sci Rep 14, 17124 (2024).
- Proudman, C. J. et al. Characterisation of the faecal metabolome and microbiome of Thoroughbred racehorses. Equine Vet. J. 47, 580–586 (2015).
- Gilroy, R. et al. Metagenomic investigation of the equine faecal microbiome reveals extensive taxonomic diversity. PeerJ 10, e13084 (2022).