New Animal Science Anywhere lesson explores dairy cow diets

“What Do Cows Eat? Deconstructing Dairy Cow Diets” lesson helps youth explore what a total mixed ration is using human food items.

A look at the supplies needed to teach this lesson. Photo by Melissa Elischer, MSU Extension.
A look at the supplies needed to teach this lesson. Photo by Melissa Elischer, MSU Extension.

There is a lot more to an animal science project in 4-H than just showing an animal at the fair. Youth spend months learning about the correct ways to care for, feed and train their animals, as well as more general science concepts. One great way to increase science learning in a 4-H project is to use the 4-H Animal Science Anywhere lessons created by Michigan State University Extension 4-H staff. These lessons provide all the instructions, supply list, discussion points and suggested adaptations to facilitate learning important science concepts with youth. Each lesson is also aligned with eight Scientific and Engineering Practices from “A Framework for K–12 Science Education.” Supplies are common household items or cost less than $10.

The new lesson, “What Do Cows Eat? Deconstruction Dairy Cow Diets,” is designed to help participants understand what and how a dairy cow is fed using human foods as a model. Many dairy cows living in barns are fed a total mixed ration, also called a TMR. This mix of feed items contains all the dietary components to ensure cows stay healthy and do their “jobs,” including producing milk, growing a calf if the heifer or cow is pregnant, and maintaining their own health and vigor.

Total mixed rations are commonly used because just like people, cows have food preferences and would sort out the best tasting parts if they could. By sorting, the animals could eat a lot of food, but might not eat what they need to be healthy and properly do their jobs. Think of a total mixed ration like a smoothie or a casserole—all the ingredients are presented in a uniform mix, so it’s really hard to pick out “the good stuff” and leave the “healthy stuff” behind.

To help youth understand how this works, human foods are used to represent different parts of a cow’s diet. Lettuce and green beans represent forages, bread represents carbohydrates, peanuts or other dried beans stand for protein, gummy bears represent vitamins and minerals, and a hard-shelled candy stands for fat. Youth talk about each item, why it is important in the diet, what items might taste the best and what are the right amounts of each to eat to maintain health and vigor.

Each ingredient starts out in a separate container to see how the participants “sort” the diet by picking up their favorite item and thinking about if eating just this food would it create a balanced diet. Youth then create their own total mixed ration with these foods to see firsthand how mixing the items makes it more challenging to sort them.

What Do Cows Eat? Deconstruction Dairy Cow Diets includes numerous ideas to adapt this lesson for the size, age range and experience of the group. This lesson also incorporates questions to help youth think about the similarities and differences between human and animal nutritional needs and efficient feeding strategies for animals.

This is only one of many Animal Science Anywhere lessons, the complete series can be found at 4-H Animal Science Anywhere lessons.

MSU Extension and the Michigan 4-H Youth Development program help to create a community excited about STEM (Science, Technology, Engineering, and Mathematics). 4-H STEM programming seeks to increase science literacy, introducing youth to the experiential learning process that helps them to build problem-solving, critical-thinking and decision-making skills. Youth who participate in 4-H STEM are better equipped with critical life skills necessary for future success.

To learn more about the positive impact of Michigan 4-H youth in STEM literacy programs and animal science programs, read our 2016 Impact Report: “Building Science Literacy and Future STEM Professionals.”

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