Gastric Ulcers and Equines

Instructional Guide

Learners will explore the equine GI system and different kinds of ulcers that horses may get.

Intended Grade Level

This lesson is intended for students in grades 9-12. Students should be familiar with general anatomy of the GI system, understand the role of stomach acid, and know that horses use microbes to ferment.

Learning objectives

• Review of equine digestion.
• Define a gastric ulcer and be able to explain why it occurs.
• Describe diagnosis, treatment, and prevention of gastric ulcers in the equine patient.

Lesson Format

This can be done in any size group. The material can be printed and disseminated. Activities require a computer with internet access

• First students will read a section on horse digestion and watch a brief video.(15 minutes)
• Next, students will read a section on gastric ulcers, learning their cause, signs and symptoms, diagnostics, treatments and prevention (25 minutes)
• Students will then work through a branching scenario case of a horse named Diesel who is suffering from a gastric ulcer (10 minutes)
• The assessment will have students draw connections from the lesson and answer three short-answer questions (10 minutes)

Lesson Background

Horses are hindgut fermenters: they have a simple (monogastric) stomach but rely on microbial fermentation in the cecum and colon to break down fibrous plants. The horse’s stomach has two main regions: the non-glandular region and the glandular region. The non-glandular region lacks acid protection and is prone to ulcers. The glandular region contains parietal cells that produce HCl and mucus cells that protect the lining. HCL is continuously secreted because horses are natural grazers.

Gastric ulcers are sores in the stomach lining caused by excess acid and lack of protective mucus. Most ulcers occur in the non-glandular region, especially when horses go long periods without forage, they consume too much grain, there is excessive exercise causing acid splash upward, or stress or NSAID use reduces protective mucus. The common signs are poor appetite, dull coat, weight loss, behavior changes, recurrent mild colic. The gold standard of diagnosing ulcers is gastroscopy (endoscopy), where a camera is passed into the stomach to view ulcers. Physical exam and history can raise suspicion but not confirm.  Prevention of ulcers is the best form of management. These include constant access to forage, low-grain diets, stress reduction, and avoiding prolonged or high-dose NSAIDs unless absolutely necessary.

Activities

Students will work through a case in a branching scenario style question. They will have the option to choose their own adventure by picking different things to explore about Diesel’s case, ultimately coming to a diagnosis and going over treatment options for this patient.

Common misconceptions and challenge points

• Students may think that hay is just filler, however hay is critical to a horse’s digestive health. It provides bulk, stimulates saliva (which helps buffer acid), and keeps digestion moving properly.
• Students may think that horses produce acid only when they eat. Remind students that unlike humans, horses produce stomach acid continuously, which is why free-choice forage is so important.
• Students may have a difficult time understanding that digestion does not only happen in their stomach. Remind students that in horses, most fiber digestion happens in the hindgut, after the stomach, through microbial fermentation in the cecum and colon.

Assessment

Students, either alone or with a partner, will think through three questions, and write up their answers. These questions represent the learning objectives and push students to draw connections between material.

Further exploration

Other chapters within this textbook may be interesting for students. Links to some of those pages can be found below:

Ulceration Upset!

Birds and Horses and Cats, Oh My!