We know that keeping horses' hindguts healthy helps the digestive tract function properly. But some researchers now believe the microflora residing in the hindgut could contribute to equine obesity.
At the 2012 Alltech Symposium, held May 21-23 in Lexington, Ky., Lucy Waldron, PhD, president and founder of LWT Animal Nutrition in Feilding, New Zealand, discussed what previous research on the subject suggests and where more research is needed to develop practical applications in horses.
A Growing Problem
Waldron relayed that obesity is prevalent in today's horses and is believed to contribute to a number of other health problems, including laminitis, developmental orthopedic disorders, insulin resistance, colic, and acidosis. And while a restricted diet and additional exercise might help some horses, Waldron cautioned that not all obese horses will respond in the same manner.
Further, she noted, "We all know there are good doers and poor doers within the horse population. Two horses could have the same paddock, the same owner, the same everything, and they could have very different weights."
Waldron said these observations have prompted researchers and scientists to look for other causes of obesity.
Research in other species prompted equine researchers to look to horses' hindguts for a potential answer to obesity. Specifically, she noted, research in mice, chickens, and pets has indicated the microbial profiles of obese animals are much different than those of non-obese animals.
One study in horses, Waldron relayed, found that one bacteria--Fibrobacter succinogenes--was more prevalent in the guts of easy keeper ponies when compared to lighter Thoroughbred horses.
She also discussed a study in which horses that consumed a prebiotic supplement had less significant microflora changes when the animals underwent a major feed adjustment than controls, indicating less digestive upset.
Waldron indicated researchers are working to determine if there could be a "perfect" microbial profile that would keep horses at an ideal weight. She suggested that supplementing yeast or a pre- or probiotic could help regulate the microbial population; however, she noted that more research is needed to characterize these supplements' mode of action.
"Controlled studies are needed, where the bacterial profiling of fat, thin, and 'normal' horses are obtained over a range of feeds," Waldron relayed. "Once these profiles are obtained, further work has to be done applying feeding strategies and supplements ... to observe any shifts in population towards the 'normal' profile."
Waldron believes that, with funding, researchers might be able to develop feeding programs designed to "optimize the horse's hindgut environment and minimize gastric and obesity issues in the future."
Disclaimer: Seek the advice of a qualified veterinarian before proceeding with any diagnosis, treatment, or therapy.