Equine Health Studies Program Research Group Contributes Research That Improves Horse Gut Health



Purina Outlasd

BATON ROUGE - The Equine Health Studies Program and the LSU Veterinary Teaching Hospital recently completed studies for Purina Animal Nutrition that resulted in the release of the feed supplement, Outlast™. The team at LSU School of Veterinary Medicine performed a series of trials in which horses were fed meals with and without Purina® Outlast™ Gastric Supplement to test the hypothesis that this proprietary mineral complex would support optimal stomach acid more than a control feed. Successfully buffering stomach acid for horses could be an important factor in managing horses’ gastric health and comfort. Horses evolved as grazing animals and as such, are meant to devote much of their day to grazing and continuous eating.


In trial 1, twenty mature, healthy Thoroghbred geldings were housed in stalls and on testing day endoscopy of the stomach was performed for collection of gastric juice for pH measurement. After collection, horses immediately received a control pellet or Outlast™ gastric supplement. Two hours later, horses received a second endoscopy for collection of gastric juice and pH measurement. In a second trial, nine Thoroughbred geldings were housed in stalls and on testing days 0, 7 and 14, the horses received either pellets alone, Outlast containing 1X the minerals and Outlast containing 2X the mineral supplement, in a randomized, crossover design. The final on-market formulation of Outlast™ gastric supplement is formulated at the 2x concentration of minerals. All horses underwent gastroscopy prior to feeding the treatments, and at 2 and 4 hours post-feeding. For both trials, gastric juice (60 ml) was aspirated from the biopsy channel and pH measured in duplicate using a benchtop pH meter. For trial 1, at 2 hours post-feeding, gastric pH was higher in the treatment group receiving Outlast™ supplement than the control group.


For trial 2, pH was significant increased at 2 and 4 hours Gastric juice pH at 2 hours was higher in the Outlast fed horses when compared to the controls. In conclusion, providing horses at risk for gastric ulcers a feed or supplement containing Purina Outlast™ Gastric Supplement may help to achieve optimal stomach acidity.  The increase in pH lasted for at least four hours under these described feeding and management conditions. For horses at risk for gastric ulcers or gastric discomfort, Purina Outlast™ Gastric Supplement may help support proper gastric pH.


  Ulcers EHSP team

Gastric ulcers in a horse's stomach as seen on an

endoscopic examination.

EHSP team scoping a horse during the study. 



For more information about the recovery stalls, please contact Julie Thomas, public relations coordinator, at 225-578-0110 or jtho279@lsu.edu.


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