There has been much published on gastric ulceration in horses in the last 10 years. In this hour we will discuss the diagnostics,
risk factors and treatment of gastric ulcers. We will concentrate on current, clinically applicable information. Below
are the abstracts from some of the studies that will be discussed.
Gastric ulcer development in horses in a simulated show or training environment. McClure SR, Carithers DS, Gross SJ, Murray MJ. J Am Vet Med Assoc 2005; 227: 775-777.
Objective–The purpose of this study was to determine if conditions simulating a recreational three day show and training activity, including
transport to and from the show grounds, stall confinement in unfamiliar surroundings, and light exercise, would be associated
with an increased incidence of gastric ulcers in horses.
Animals–Twenty (20) American Paint Horses, including 2 stallions, 12 geldings and 6 mares, between 17 months and 21 months of age
were used in this study. Prior to study initiation, the horses were housed in outside paddocks with no environmental controls,
other than a windbreak, and no bedding was provided. The horses were fed 2 pounds of oats daily in the morning and were given
grass/alfalfa mix hay ad libitum. They had free access to well water via large automatic waterers.
Procedure– Horses with no gastric ulcers, as determined by endoscopic examination study Day -1, were randomly assigned to two similar
groups of 10 horses each. Ten control horses were maintained on site with no changes in management parameters. The second
group of ten horses was transported via trailer for 4 hours on Day 0 to another site, placed individually in stalls, fed twice
daily and exercised twice daily for 3 full days. On Day 4 they were transported back to the original site via trailer for
4 hours. On Day 5, endoscopic examinations were performed on all horses to assess gastric mucosa status.
Results–Horses that were transported and housed off-site had a significantly (p<0.05) higher incidence of hyperkeratosis and reddening
of the gastric mucosa than control horses. Two control horses and 7 principal horses developed gastric ulcers by Day 5.
The ulcer scores of the principal horses increased significantly (p<0.05) from Day 0, but ulcer scores in the control horses
did not change significantly from Day -1.
Conclusion and Clinical Relevance–These findings indicate that activities that are typically associated with participating in a 3-day horse show are ulcerogenic
and that squamous gastric ulcers can develop under these conditions within 5 days.
Efficacy of omeprazole paste for prevention of gastric ulcers in horses in race training.
McClure SR, White GW, Sifferman RL, Bernard W, Doucet M, Vrins A, Holste JE, Fleishman C, Alva R, Cramer LG J Am Vet Med Assoc 2005;226:1681-1684.
Objective—To determine the minimal effective dosage of omeprazole oral paste for the prevention of naturally occurring ulcers in horses
starting race training.
Procedure—Horses in the dose selection portion of the study were sham-dose treated or received 1 mg (0.45 mg/lb) or 2 mg (0.9 mg/lb)
of omeprazole/kg, PO, every 24 hours for 28 days; or 4 mg of omeprazole/kg (1.8 mg/lb; loading dose) PO, every 24 hours for
4 days, then 1 mg or 2 mg of omeprazole/kg, PO, every 24 hours for 24 days. Horses in the dose confirmation portion of the
study were sham-dose treated or received 1 mg of omeprazole/kg, PO, every 24 hours for 28 days. Gastric ulcer scores at the
beginning and end of the study were compared.
Results—Sham-dose treated horses had significantly higher ulcer scores than horses treated with any of the omeprazole dosages evaluated.
Among horses treated with omeprazole, there was no significant interaction of dose (1 or 2 mg/kg) and loading dose; therefore
the lowest effective dose (1 mg/kg) was evaluated in the dose confirmation portion of the study. In the dose confirmation
study, 4 of 39 (10%) of the sham-dose treated horses remained ulcer free, which was significantly different from the number
of horses (3⅓8 [82%]) receiving 1 mg of omeprazole/kg that remained ulcer free.
Conclusions and Clinical Relevance—Results indicated that omeprazole administered at a dosage of 1 mg/kg, PO, every 24 hours for 28 days was effective for prevention
of gastric ulcers in horses starting race training.