Fore stomach, true stomach, red stomach, blue stomach

Instructional Guide

Learners will explore why and how some animals can eat grass, while others cannot.

Intended Grade Level

This lesson is intended for students in grades 6- 8. Students should be familiar with general anatomy of the GI system of a monogastric animal.

Learning objectives

• Students will be able to identify the important GI structures in the horse
• Students will be able to identify the important GI structures in the cow
• Students will compare and contrast the functional anatomy of the GI tract in a horse and cow

Lesson Format

Student page

This can be done in any size group. Activities require access to a computer and the internet.

• First students will read an introduction to the topic, prompting to think about why some animals can eat grass, whereas others cannot. (5 minutes)
• Next, students will read about the horse and the cow GI systems (10 minutes)
• Students will then play a game to put the order of the GI system for both the cow and the horse in the correct sequence (10 minutes)
• The assessment will focus on matching the part of the GI system to its function (5 minutes)

Lesson Background

Each species of animal’s GI tract is designed to maximize nutrient absorption from their diet. As such, each GI tract has different adaptations to ensure this is a possibility.

In horses, the cecum and the colon contain good and helpful bacteria (microbes) that allow the horse to break down the grass they ate. The colon is very long to allow the horse maximum time for their body to absorb nutrients from their food.

In cows, the rumen and the four-chambered stomach system is what allows cows to eat grass. The rumen has microbes which break down components of grass, and allows for the fermentation process to occur to maximize nutrients absorbed. The rest if the four-chambered system also aids in maximizing nutrient absorbtion from low-nutrient foods such as grass.

Activities

Students will be asked to place the order of the GI tract for both the cow and the horse in the correct sequence. The cow’s GI tract is just labels of the parts; the horse’s GI tract is images with labels.

Common misconceptions and challenge points

Students may have a difficult time understanding why horses and cows have different GI tracts, but they can both have grass. Explain that they evolved differently, and have different diets, as well as different uses of nutrients, so have different needs. As we learned throughout this lesson, different needs means a different GI tract. Cows use their rumen to help digest grass and horses use their cecum to digest grass.

Assessment

Students will be asked to match the part of the GI tract with its function by dragging and dropping the description into the properly labeled box.

Further exploration

Other lessons within this textbook explore a similar topic and may be interesting for learners. These can be found linked below:

Multiple GI Tracts? Jeez!

Birds and Horses and Cats, Oh My!