Could Season Impact Equine Obesity?

Could Season Impact Equine Obesity?

Researchers found that obesity levels rose significantly from 27% at winter's end to 35% during the summer.

Photo: Thinkstock

If your horse is overweight, you are not alone. Equine obesity has risen dramatically in recent years. Researchers have been studying the issue in hopes of learning more about the trend, but as it turns out, many have left out one important factor: seasonal variation.

British researchers recently set out to examine the prevalence and risk factors associated with equine obesity at different times of year, taking seasonal variation into account.

“I don't think obesity is acceptable at any time of year, as it carries a large number of associated health risks,” said Sarah Giles, a PhD candidate at the University of Bristol, in England, and lead researcher of the study. "However, some breeds do naturally store fat during summer months for use during winter conditions."

Giles and her fellow researchers used the 9-point Henneke body condition scoring system and belly girth measurements (both measured by a single trained observer) and owner questionnaires (including age, breed, sex, additional feed, exercise regimen, etc.) to assess obesity in 96 leisure horses with six or more hours of daily pasture turnout. To compare seasonal variation, the team collected data at the end of winter and during the summer.

The team found that obesity levels rose significantly from 27% at winter’s end to 35% during the summer, and that seasonal variation in body condition was lower in obese equids than non-obese. They also found that supplemental feed and exercise had little to no effect on obesity levels, but grass restriction had the greatest effect in reducing seasonal change in belly girth.

Study findings also revealed that certain types of horses, such as breeds native to the U.K. and older horses, were most likely to be obese.

In application of these findings, Giles said, “Winter is the best time of year to reduce a horse or pony’s body condition back down to an acceptable level; it is an opportunity to work with, as opposed to against, their natural seasonal weight loss mechanisms.”

During the summer Giles suggests ensuring the pasture size is appropriate for the number of horses and strip grazing horses (using movable fencing to limit a grazing area) if necessary. She stresses that exercise is the best method of maintaining appropriate body condition.

“I wouldn't advocate stabling as a preventive measure, as in my opinion the health benefits of having horses and ponies outside on pasture, living in their natural environment outweigh the costs,” she said.

The study, "Obesity prevalence and associated risk factors in outdoor living domestic horses and ponies," was published in March in PeerJ.

About the Author

Casie Bazay, NBCAAM

Casie Bazay holds a bachelor of science degree in education from Oklahoma State University. She taught middle school for ten years, but now is a nationally certified equine acupressure practitioner and freelance writer. She has owned Quarter Horses nearly her entire life and has participated in a variety of horse events including Western and English pleasure, trail riding, and speed events. She was a competitive barrel racer for many years and hopes to pursue the sport again soon.

Stay on top of the most recent Horse Health news with FREE weekly newsletters from Learn More