Researchers found that obese Standardbred horses lost significant amounts of body weight and condition when fed only hay, but the Andalusian and pony groups did not lose weight as easily.
Obesity in horses and ponies has become a significant problem, often increasing the risk of diseases such as insulin resistance, laminitis and equine metabolic syndrome. It has been thought that weight loss may be achieved more easily in some breeds compared to others, and should be carefully monitored to avoid adverse effects including hyperlipidemia (abnormally high lipid concentrations in the blood).
In a study conducted in the United Kingdom, obese (BCS ≥7) ponies, Standardbreds and Andalusians were used to compare weight loss with and without the addition of daily exercise. A total of 12 equines were studied. A body condition score (BCS) of ≥ 7 is characterized by a moderate to obvious crease down the back; fat accumulation over the ribs, tail head and behind the shoulders; and a cresty neck.
All animals were housed and fed individually on a dry lot (dirt paddock) for up to 12 weeks on a restricted diet of 1.25% body weight of grass hay daily; nutritionists generally recommend a daily intake of 2% body weight. Half of the horses were exercised daily on a horse-walker for 25 minutes, while the other 6 were not exercised. Researchers recorded changes in body weight, BCS, and body fat percentage. Once the animals reached a BCS of 5, considered an optimal body condition score, the dietary restriction was stopped.
Researchers found that obese Standardbred horses lost significant amounts of body weight and condition when fed only hay, but the Andalusian and pony groups did not lose weight as easily. During the dietary restriction, Standardbreds reduced their body fat by 57% body fat while the other two breeds reduced their body fat by only 27%. While it took the Standardbreds 6 weeks to achieve a BCS of 5, it took ponies and Andalusians 12 weeks to achieve the same results. Amount of exercise was found to have no effect on rate of body weight loss or reduction of BCS and body fat%.
This study illustrates the differences in the ability of different horse breeds to lose body weight. While exercise was not found to contribute to weight loss in this study, it is still advised for horses and has many physiological benefits.
Summarized by Emily Glunk, MS, University of Minnesota