Gastric ulcer update and review (Proceedings)

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.

Design—Prospective study.

Animals—175 horses.

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.

Efficacy of omeprazole paste for prevention of recurrence of gastric ulcers in horses in race training.

McClure SR, White GW, Sifferman RL, Bernard W, Doucet M, Huges FE, Holste JE, Fleishman C, Alva R, Cramer LG.J Am Vet Med Assoc 2005;226:1685-1688.

Objective—To determine whether omeprazole oral paste administered at a dosage of 0.5 or 1.0 mg/kg, PO, every 24 hours would effectively prevent the recurrence of gastric ulcers in horses in race training.

Design—Prospective study.

Animals—135 horses.

Procedures—Horses with gastric ulcers were treated with omeprazole at a dosage of 4 mg/kg, PO, every 24 hours for 28 days. Horses in the dose selection portion of the study were sham-dose treated or received 0.5 or 1.0 mg of omeprazole/kg, PO, every 24 hours for an additional 28 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 an additional 28 days. Gastric ulcers were scored before and after the preventative phase of the study (day 28 to day 56) via gastroscopy and ulcer scores were compared.

Results—Sham-dose treated horses and horses receiving 0.5 mg of omeprazole/kg had significantly higher ulcer scores than horses receiving 1.0 mg of omeprazole/kg. There was a significant difference between the number of horses receiving 1.0 mg of omeprazole/kg (38/48 [79%]) that remained ulcer free and the number of sham-dose treated horses (7/44 [16%]) that remained ulcer free.

Conclusions and Clinical Relevance—Omeprazole oral paste administered at a dosage of 1 mg/kg, PO, every 24 hours for 28 days was effective for prevention of recurrence of gastric ulcers in horses in race training.

Prevalence of Gastric Ulcers in Show horses. McClure SR, Glickman LT, Glickman NW. J Am Vet Med Assoc., 1999;215:1130-1133.

Objective—To determine prevalence and risk factors for gastric ulcers in show horses.

Design—Field survey.

Sample Population—50 horses in active training that had been transported to at least one event in the 30 days prior to endoscopy.

Procedure—Interview of owner, physical examination, serum biochemical analysis and CBC count, and gastric endoscopy were performed.

Results—Gastric ulceration was detected in 58% of the horses. Horses with a nervous disposition were more likely to have ulceration than quiet or behaviorally normal horses. Horses with gastric ulceration had significantly lower RBC counts and hemoglobin concentrations than those without ulceration.

Conclusions and Clinical Relevance—Show horses have a high prevalence of gastric ulceration. Lower RBC counts and hemoglobin concentrations may be the result of chronic gastric ulceration.