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 Horses are best fed little and often, as large meals fed all at once can overwhelm the foregut. © KER

Barnyard Chemistry: pH & the equine digestive tract

By Kentucky Equine Research

In-depth discussions of the equine digestive tract invariably mention pH, especially in reference to the stomach and hindgut. What is pH and how does it factor in the well-being of horses?

In simplest terms, pH is a numeric scale used to measure acidity or basicity of any solution — grapefruit juice, drinking water, bleach, digestive secretions. The scale generally runs from 0 to 14, with 0-6 indicating acidity, 7 representing neutrality, and 8-14 signifying basicity. Useful application of the pH scale reaches far beyond household items, even into the barnyard.

THE STOMACH

As part of the digestion process, the horse’s stomach manufactures and secretes hydrochloric acid, creating a naturally acidic environment. The pH of the stomach fluctuates based on contents, both the amount and type of feed and forage. “A range of pH readings has been recorded in the stomach; the lowest of which is less than 2, the highest of which is greater than 6. Even in the best of circumstances, the stomach is an acidic environment,” said Catherine Whitehouse, M.S., a nutritionist with Kentucky Equine Research (KER).

In nature, the horse employs two main protective strategies to maintain stomach health: (1) near-continual consumption of forages, which keeps the stomach full, thus avoiding acidic sloshes; and (2) production and swallowing of saliva, which buffers, or neutralises, the acidic environment...

Read the full article in the June 2021 issue of Equestrian Life here!