Ulceration Upset! Exploring Equine Gastric Ulcers

Amelia Adelman, Sarah Schmidt, Elizabeth Wal

Goal of Section: 

Students will explore the difference between glandular and non-glandular ulcers and discuss the clinical signs and common preventatives for gastric ulcers in horses.

Intended Grade Level: 

Intended for high school students (grades 9-12). Students should become familiar with the general anatomy of the GI system in horses and the signs and treatment of gastric ulcers.

Learning Objectives: 

• Students will be able to explain the general anatomy and flow of food through the equine digestive tract
• Students will be able to correctly describe the difference between glandular and non-glandular ulcers
• Students can identify clinical signs of gastric ulcers and how the normal functional anatomy of the GI tract is affected
• Students should be able to describe different treatments for gastric ulcers and how they affect the body

Lesson Format

This lesson can be taught in any size group. This material can be printed out for students to reference individually or can be projected so that the entire class can see the material at once. Activities may require a printer. Small white boards for table groups of students will be needed for some activities as well. Dry erase markers and colored pencils/markers are also required. 

1. Have students read over background knowledge section on equine GI anatomy and process of digestion (can be done out loud with student volunteers or give students 5-10 minutes to read section individually).
2. Ask students to write the typical components of a horse’s diet on the white board, along with a drawing of the movement of food through the equine digestive tract.
3. Assess students on their new knowledge of the equine digestive tract by asking them to discuss and write on their white boards what they think the difference between glandular and non-glandular stomach ulcers entails, follow-up discussion with diagram of the equine stomach and its different regions. Also, ask students to write down any pre-existing preventative measures or clinical signs they may have know prior to this lecture.
4. Show students video covering physiology of ulcers, clinical signs, etc. Discuss comparisons to their whiteboard answers.
5. Provide coloring sheet of digestive tract linked to student page as printed copies for students to color in class or on their own time.
   1. Equine Digestive Tract : Have students use different colors for the different parts of the digestive tract. _{(Taken from Cornell University Animal Science Department’s “Horse Guts and Math”).}
   2. Equine Stomach: Have students label and color the glandular and non-glandular regions. _{(Taken from Monique Warren’s “Preventing Equine Gastric Ulcers- How Forage Buffers Acid”).}
6. _{Ask students to complete} the crossword puzzle either in class or on their own time:
7. Ask students to take the assessment on the bottom of the page to test their knowledge.

Lesson Background

Horses are “hindgut fermenters.” This means that they are monogastric (single-stomached) herbivores that use the digestive organs following the small intestine to further digest tough plant material. The equine digestive process is as follows: oral cavity (grinds food) –> esophagus –> esophageal sphincter (discuss here how the very strong sphincter muscles prevent horses from being able to vomit like other animals) –> glandular stomach –> non-glandular stomach –> small intestine –> cecum–> large intestine –> rectum. The glandular stomach secretes HCl, which is a highly acidic compound that breaks down proteins. The stomach is lined with a protective mucus in this area due to its highly acidic nature. After food goes through this portion of the stomach, it goes to the non-glandular region, which does not contain any digestive acids.

Due to the highly acidic nature of the glandular stomach and the non-glandular stomach which is not lined with a protective mucus, stomach ulcers are a major problem for horses when the two regions interact inappropriately. Horses are designed to eat continuously throughout the day, and eat high forage diets. For this reason, their stomach continuously secretes HCl whether or not they are eating. If they are fed high grain diets or only fed large meals a few times a day, their stomach will build-up HCl in the glandular region and if it is only digesting feed a few times per day, the increased acid can cause damage to the non-glandular region that is not protected by a mucus layer. This is why it is important for a horse to eat continuously throughout the day and to avoid highly stressful situations or prolonged stress, which can irritate the GI system as well.

Clinical signs of gastric ulcers include significant weight loss, change in eating habits, decreased performance in the horse’s given discipline, mild colic signs, and signs of discomfort (biting at stomach) or irritability.

Preventative treatment of gastric ulcers includes ensuring that the horse is turned out with other horses and allowed to properly socialize to reduce stress. Horses are herd animals and will become depressed or stressed if they are not permitted to interact with other horses or people. Providing continuous access to forage (hay or grass), as well as maintaining a proper balance of concentrate to roughage will also help neutralize stomach acid build-up and resulting ulcers from forming. If the horse is on any sort of NSAID long-term, providing gastroprotective drugs to help combat any sort of irritation to the gut lining will be beneficial as well (if students are interested, can provide some specific examples of gastroprotective drugs and ask if anyone has heard of/used any of them before). Some specific gastroprotective drugs include Omeprazole or Sucralfate.

Student Page

Activities

1. White board activities: pass out white boards and dry erase markers to each table group of students. Ask students to first write out typical components of a horse’s diet, followed by a flow chart of the movement of food through the equine GI system, ending with the differences between the glandular and non-glandular regions of the stomach and including any pre-existing knowledge on the clinical signs and preventative measures students may already know.
2. Coloring page activity: hand out pre-printed copies of equine coloring pages to students, provide colored pencils and/or markers. Give students 5-10 minutes to color pages.
3. Crossword puzzle: Allow students to try for 10-15 minutes on their own, then bring them together and see if they can figure it out as a group if they don’t complete it before then.

Specific Questions to Ask:

• What are the typical components of a horse’s diet?
• What is the typical flow of food throughout the horse’s digestive tract? Please create a flow chart illustrating all of the different components and draw the route food would take through the system.
• What are the differences between the glandular and non-glandular regions of the equine stomach?
• Do you know of any clinical signs or preventative treatments to help combat gastric ulcers?

Common misconceptions and challenge points

• The difference between glandular and non-glandular region of the stomach may be confusing for students. Reiterate the fact that the glandular stomach contains HCl secreting cells that are extremely acidic and break down food particles into more easily digestible compounds. The non-glandular region does NOT contain these cells so is highly susceptible to damage from the acid created in the other region.
• One of the clinical signs of gastric ulcers is colic. Some students may not be familiar with this term or understand what colic entails. Colic is a generalized term for abdominal pain in horses that can be caused by many different things, such as ulcers, impaction/obstruction within the GI tract, twisting of the small intestine, stress, etc. Signs of colic can include pawing or biting at the stomach to indicate discomfort, stretching/rolling, sweating, loss of appetite, restlessness, stomach gurgling, etc.

Assessment

• see student page

Further exploration

Provided below are some further links to share with students if they would like more information on equine gastric ulcers.

https://extension.umn.edu/horse-health/stomach-ulcers-your-horse

https://ceh.vetmed.ucdavis.edu/health-topics/equine-gastric-ulcer-syndrome