08/08/2026
This year I have decided to share a bit more about the ins and outs of how we do things here at Glenhill Sporthorses, with the focus on our breeding and foaling down and raising practises. This starts well before the foal is born, or even conceived! The most important thing about being a good breeder in my opinion is the feeding of both the mare ( donor mare prior to breeding, recip mare while carrying and the foal once weaned until 3 years old!). To start, I’ll share this post about the pregnant mares as we are getting to the pointy end of the stick now!
We are incredibly careful with the weight of our carrying mares. It sets the foal up for life. A fat mare has trouble foaling, the foals are affected in the womb and after birth. As such, we have very good grass paddocks our pregnant mares are on year round. We start out with Balanced for them until they get closer to foaling and then they switch to Mitavite Studgro. But this all depends on the weight and condition of the mare. Extruded feeds are extremely important! And we do not give extra additions like rolled oats, or individual grains etc ( been there, done that and learned the lesson!!). I will make an effort to continue to post our program, but please feel free to ask any question here and I will answer!!
Hygain
The (not-so) Hidden Risk: Mare Obesity and Its Impact on Foals
⚠️ Choose your breeder wisely - especially if you’re purchasing a breed with a predisposition to equine metabolic syndrome. These include ponies, arabs, andalusians, warmbloods, quarter horses, paints, stockhorses and their related crosses.
✅ Ethical breeders are now prioritising the long-term health and longevity of their foals—and the breed as a whole—over short-term success in the show ring. Across the industry, responsible breeding programs are shifting away from obese brood mares, recognising that producing sound and metabolically healthy animals is far more valuable than breeding purely for what wins ribbons today.
This change is happening because the science is clear: over-conditioning mares doesn’t just add extra weight—it programs foals for metabolic disease, orthopedic problems, and reduced welfare from birth.
⚠️ The Consequences of Maternal Obesity
The evidence is compelling—and the consequences for foals are serious:
• Orthopedic disease (OCD) – One study reported that 53% of foals from obese mares developed osteochondrosis lesions by 12 months of age, compared to much lower rates in foals from mares in ideal condition. OCD can compromise long-term athletic soundness and affect long-term mobility.
• Metabolic dysfunction – Foals born to obese mares are often insulin resistant, and this metabolic dysregulation persists into adolescence. Insulin resistance increases the risk of later-life conditions such as laminitis and equine metabolic syndrome.
• Chronic low-grade inflammation – Both mares and foals from obese pregnancies show elevated inflammatory markers. Persistent inflammation early in life can affect joint health, immune function, and even heat tolerance as the foal matures.
• Colostrum & milk quality changes – Obese mares produce less energy-rich colostrum and milk with a higher pro-inflammatory profile and altered omega‑3 to omega‑6 ratios. This affects foal immunity, gut health, and early musculoskeletal development.
• Epigenetic programming before birth – Even embryos from obese mares show altered gene expression related to lipid metabolism, inflammation, and mitochondrial function, meaning the foal’s health is “programmed” long before it is born.
‼️ These aren’t cosmetic issues—they are welfare and performance concerns that can affect a foal for life.
✅ If you’re looking to buy a foal or youngster, the best breeders—those shaping the future of the industry, are aiming to maintain mares at healthy body condition scores, avoid overfeeding, and ensuring they are producing foals that will remain sound and athletic for years, not just for a few fleeting show seasons.
In many ways, the industry is beginning to reward this shift. Buyers and owners are increasingly valuing horses that are metabolically healthy, trainable, and sound into adulthood—a trend that ethical breeders are leading. As more breeders adopt this approach, it becomes the standard that others feel compelled to follow.
References:
Robles, Morgane, et al. "Obesity during Pregnancy in the Horse: Effect on Term Placental Structure and Gene Expression, as Well as Colostrum and Milk Fatty Acid Concentration." Veterinary Sciences 10.12 (2023): 691.
Robles, Morgane, et al. "Maternal obesity increases insulin resistance, low-grade inflammation and osteochondrosis lesions in foals and yearlings until 18 months of age." PLoS One 13.1 (2018): e0190309.
