Objective—To measure pH, volatile fatty acid (VFA)
concentrations, and lactate concentrations in stomach
contents and determine number and severity of
gastric lesions in horses fed bromegrass hay and alfalfa
Animals—Six 7-year-old horses.
Procedure—A gastric cannula was inserted in each
horse. Horses were fed each diet, using a randomized
crossover design. Stomach contents were collected
immediately after feeding and 1, 2, 3, 4, 5, 6, 7, 8, 10,
12, and 24 hours after feeding on day 14. The pH and
VFA and lactate concentrations were measured in gastric
juice. Number and severity of gastric lesions were
scored during endoscopic examinations.
Results—The alfalfa hay-grain diet caused significantly
higher pH in gastric juice during the first 5 hours
after feeding, compared with that for bromegrass hay.
Concentrations of acetic, propionic, and isovaleric acid
were significantly higher in gastric juice, and number
and severity of nonglandular squamous gastric lesions
were significantly lower in horses fed alfalfa hay-grain.
Valeric acid, butyric acid, and propionic acid concentrations
and pH were useful in predicting severity of
nonglandular squamous gastric lesions in horses fed
alfalfa hay-grain, whereas valeric acid concentrations
and butyric acid were useful in predicting severity of
those lesions in horses fed bromegrass hay.
Conclusions and Clinical Relevance—An alfalfa haygrain
diet induced significantly higher pH and VFA concentrations
in gastric juice than did bromegrass hay.
However, number and severity of nonglandular squamous
gastric lesions were significantly lower in horses
fed alfalfa hay-grain. An alfalfa hay-grain diet may buffer
stomach acid in horses. (Am J Vet Res 2000;61: