Tuesday, June 25, 2024
HomeNotes From KathyWhat Should I Do About Pasture Weeds?

What Should I Do About Pasture Weeds?

This is an example of the progress trained heifers made on reducing leafy spurge in pasture at Grant-Kohrs Ranch National Historic Site in Deer Lodge Montana. Pictures were taken in early August of 2005. After the fence was taken down and cattle had access to a mown hayfield, they returned to this pasture on their own and finished off the leafy spurge.
This is an example of the progress trained heifers made on reducing leafy spurge in pasture at Grant-Kohrs Ranch National Historic Site in Deer Lodge Montana. Pictures were taken in early August of 2005. After the fence was taken down and cattle had access to a mown hayfield, they returned to this pasture on their own and finished off the leafy spurge. Click on the picture to read more about cattle learning to eat leafy spurge.

Back in the Spring of 2010, the Agriculture Research Service (ARS) in Miles City, Montana put out a press release announcing an online calculator that could tell producers how many more cattle they could raise if they were able to eliminate one or two widespread invasive plants. Matt Rinella, the rangeland ecologist who developed the tool, used it to estimate that ranchers in a 17-state region could raise 200,000 more cows a year and save tens of millions of dollars if leafy spurge were eliminated. Of course how to eliminate leafy spurge, or any other weed, is a problem we’ve yet to solve.

Can’t Beat ‘Em? Eat ‘Em!

In 2004, I developed a method to teach cows (or whatever livestock you raise) to eat weeds. So when I saw the ARS announcement I looked at Matt Rinella’s results from a completely different perspective. If cattle can eat leafy spurge (and I have actually trained cattle to eat this plant), that means that there is enough forage available right now for 200,000 more cattle.  If we went straight to grazing leafy spurge instead of trying to eliminate it, we’d save even more than the tens of millions estimated by Rinella.

Why Do I Have To Teach My Livestock to Eat Weeds?

We know that animals learn what to eat from their mothers and their herd mates.  As long as they have enough familiar food to eat, they just won’t try anything that hasn’t been eaten by someone they know.  (Check out this short video to see how strong this effect can be!)  In addition, since we have always considered grass to be good and weeds to be bad, we’ve often managed our pastures in ways that allow our livestock to eat only the things they’re most familiar with.

Got Weeds?  You’re in Luck!

There are two really great things about having weeds in your pastures. First, they are very resilient, as you’ve probably noticed already. They come back regardless of drought or weather, so if your animals are eating them, it means they’ll always have something in their pastures.  Weeds are also very nutritious. After testing many varieties of weeds, I learned that as general rule, they have more protein than grass, and they are more digestible as well. If you’ve got some high protein weeds in your dry grass, you’re also in luck.  The protein in the weeds helps a ruminant digest dry, fibrous plants and turn them into nutrients the body needs.  (Yes, that’s a third benefit, but who’s counting?)

You Can Teach 25 Cows to Eat Weeds in 8 Hours Over 7 Days For Less Than $100

Here are the basics of the simple steps for teaching your livestock to eat weeds.  I cover them in greater depth in this past On Pasture article. You can also purchase a book or DVD at this Spring’s discounted price to get all the details.

DontEatTheseWeeds1. Know Your Plant

All plants contain toxins, but there are not that many with toxins at such high doses that they will kill or harm your animals. Before you begin training, be sure that your plant is safe for your animals to eat.  (See the list of safe plants included with this article, or contact me if your plant is not on this list.)

2.  Choose Your Trainees

Any of the animals you have can learn to eat new foods.  You can teach your replacement heifers,  cow-calf pairs, and even your stockers.  Training animals who will be staying at your place is a good idea because then they can teach their offspring and herd mates.  Still, though stockers may be heading off your place at the end of the grazing season, training a small group of them as they’re getting used to your operation, and letting them train the rest of the herd, is a quick and easy thing to do.

You will be using your trainees’ natural competitiveness to encourage them to try new foods, and to make that work best you need a “herd.”  After 10 years of training, I’ve learned that a herd starts at about 12 animals because that’s the point at which people can no longer keep track of them as individuals and treat them as special.  I like training 25 to 50 because it’s efficient and no harder than working with 12.

3. Create a routine that makes the unfamiliar seem familiar.

All creatures are naturally afraid of trying new things.  We want to get rid of that fear by showing them that when we give them new foods, it’s always going to be something good to eat.  Here’s how we do that:

Every morning and afternoon for 4 days, I feed a nutritious but unfamiliar food.  That means that I go down to the feed store and buy bags of grain that are high in protein (livestock candy!) focusing on foods that they haven’t tried in a variety of flavors, textures, sizes and shapes.  I buy 8 different things, 1 fifty-pound bag per 25 animals.  I pick a time to come every morning and every afternoon, and give them one of the new foods.  I typically serve them in the large supplement tubs, 1 tub per every 3 trainees so that they’ll have to fight and grab to get the good stuff.

On the fifth day I skip the morning feeding.  Then I cut weeds, serve them in the tubs as usual with a little bit of one of the foods they’ve tried earlier that week.  I repeat this on day 6 and on day 7 I feed the weed plain.  (Actually, sometimes I can see in the pasture that they’ve already started eating the weed on day 7, and if so, I stop.)  Your cattle will start eating the weeds in pasture, and the more they practice, the better they’ll get at doing it.  Then they’ll start to add other weeds on their own without any more work on your part.  What a deal!

Let’s make Matt Rinella’s dream of 200,000 more cows a reality!

When I first figured out how easy it was to teach cows or any animal to eat weeds, it seemed such an obvious and easy solution to a problem affecting so many, that I thought farmers and ranchers would swoon with delight and run out and teach their animals. But I forgot how long it can take folks to change. It turns out that it takes 10 years of data before farmers and ranchers will consider something new, and then another 10 years after that until the practice is common. So I did lots of demonstrations and presentations, wrote a book, created videos, and even started On Pasture as a way of helping folks learn more about good grazing.

If you’re interested in taking advantage of weeds as the excellent forage they are, here’s a link to the books and resources I have that can help you get started. You’ll find:

• The ebook set – Cows Eat Weeds, with the process, what I learned along the way and how I solved problems I encountered; and Edible Weeds & Training Links, a list of over 120 weeds and whether they’re safe to graze and a quick start recipe to get you going at home.

• Links to On Pasture articles about training, and different weeds animals have learned to eat, and

• Links to my Youtube channel with videos showing the training in action.

My real hope is that some day everyone will just think it’s normal to teach their livestock to eat weeds and most won’t even know who I am. That’s probably not something I’ll see in my lifetime, but I’d love your help in getting there. 🙂

Thanks for reading!


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Kathy Voth
Kathy Vothhttps://onpasture.com
I am the founder, editor and publisher of On Pasture, now retired. My career spanned 40 years of finding creative solutions to problems, and sharing ideas with people that encouraged them to work together and try new things. From figuring out how to teach livestock to eat weeds, to teaching range management to high schoolers, outdoor ed graduation camping trips with fifty 6th graders at a time, building firebreaks with a 130-goat herd, developing the signs and interpretation for the Storm King Fourteen Memorial trail, receiving the Conservation Service Award for my work building the 150-mile mountain bike trail from Grand Junction, Colorado to Moab, Utah...well, the list is long so I'll stop with, I've had a great time and I'm very grateful.


  1. What’s four things do you like to use for feed for the first four days that you think work the best? Something that you know they are going to eat and clean up?

    • Hi Kevin,

      What cows like depends on the herd and how adventurous their palates are. And they don’t have to eat all of their snacks in order to become successful weed eaters.

      I’ve tried all kinds of feeds. The only thing I’ve found that most cows didn’t care for was cottonseed meal. For more, check out this link: The Cows Eat Weeds and Edible Weeds and Training Recipe ebook set is helpful. In the book I cover the problems I ran up against and the solutions that I discovered. The Edible Weeds & Training Recipe booklet has a list of all the weeds I know about, and the training recipe lays out the feeds you could use, what you might see along the way, and what to do at every step along the way if you have a problem. You can also scroll down past the ebook set and you’ll find a whole list of articles on teaching livestock to eat weeds. https://onpasture.com/turn-your-livestock-into-weed-eaters/ Just scroll down a bit. The first one in the list includes a list of what I’ve used for the first four days.

      Hope that helps!


    • Hi David,
      I’m assuming there’s a typo there and you’re asking about milkweed. Do not train your livestock to eat this weed. All are either neurotoxic or cardiotoxic and very low percentages of an animal’s body weight are enough to be fatal (.5 – 2%). Some milkweeds in the West are particularly dangerous and were responsible for the deaths of hundreds of sheep in the western U.S. in the 1900s. All animals, including chickens are susceptible. In addition, the toxins in the plant are not reduced by drying, so they continue to be dangerous if hayed.

      That said, I once went to Vermont where a farmer wanted to train his cows to eat a broadleafed variety growing in his pasture. The plant was sparsely scattered and while there I saw a cow eat a milkweed and saw that there were many plants that had been bitten off. This speaks to the fact that the dose is the problem, and if animals only consume small quantities mixed with many other feeds, they are still safe. But that does not mean I would promote animals grazing them. I would be especially careful if you have dense stands as it would be easy for an animal to take one bite too many.

      I hope that’s helpful. And if you didn’t mean milkweed, do let me know! 🙂

      • I did mean milkweed- thank you! I’ve been trying to control milkweed by going into a paddock after I’ve moved the cows and using a hand weed whacker ( you know, you swing it like a golf club) to cut down the milkweed. Is this just a waste of time and effort??

        • I don’t think it’s a waste of time and effort, especially if it seems like the plant is increasing in your pasture. You have to do something to set it back a bit. One of my poisonous plants books suggests digging out the plants because they spread through underground roots (rhizomes) as well as by seed.

          • Yes, they do spread through the roots – digging out would be a major undertaking. May try using a propane weed burner – but only when it’s wet!! Thanks for your quick responses. Hope all is well with you and yours!!

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