Kathy Voth, On Pasture Editor and Contributor
(Previously published in On Pasture: November 15, 2021)
In this 
month’s Thinking Grazier, Darrell Emmick points out the importance of understanding what a cow needs to be most productive and how she chooses those foods. It’s something I’ve studied for many years used to add nutritious foods to livestock diets.
If you’ve spent much time at all at On Pasture, you know I’m talking about weeds. They turn out to be highly nutritious, very resilient forages, and if your livestock ate them you’d have 43% more forage, and a lot fewer worries. All it takes are the simple training steps I put together, and in just eight hours spread over seven days, you’ll have weed eating livestock.
Yes, I know it sounds crazy. But it’s all based on three decades of research into how animals choose what to eat. I just read all the research, became a “Thinking Grazier,” and translated the science into something beneficial to graziers everywhere.
The foundation is an improved understanding of “Palatability”
Palatability isn’t a matter of taste. It’s really a result of nutrients and toxins in a food in combination with an animals physical requirements that determines if a food tastes good or bad It works like this:
Nutrients Are Good, Toxins Are Not So Good
Nutrients tend to increase palatability, and toxins tend to decrease it. All plants have toxins that change over the course of the growing season, so, as the research I read demonstrated, livestock are constantly adjusting what they eat and mixing foods to prevent bad feedback.
The best way to see this working is to let animals themselves show you. This video shows how feedback from nutrients, or the lack of good feedback affect how two groups of sheep see straw as a food. The group that has good experience with nutritional feedback from straw will eat it, while the other group won’t.
This video shows what happens when animals encounter toxins in foods. They avoid that food or reduce the amount they eat depending on the dose they experience. This is important because all foods contain some kind of toxin, so creatures need to be able to learn from nutritional feedback which foods to avoid, or how much of each one to eat.
What Can You Do With This?
For starters, look out at your pasture and consider what Darrell had to say about how weight gains increased when he managed pastures for a higher nutritional plane. What could that do for your livestock? Then, how might you put together a grazing management plan to make that happen? (We’ll be providing tools to help you with that in the coming New Year.)
If you’re interested in turning your livestock into weed eaters, I’ve added resources for you in Premium Content. There’s a “Recipe” for teaching cows to eat Canada thistle that you can use to teach your livestock to eat any edible weed. There’s also an ebook with information on all the most commonly targeted weeds and whether or not they’re edible. Finally, there’s a technical note on how to manage your livestock to meet your weed management goals.