Published Dec 21, 2017

Grazing Weeds: A Strategy for Resilience — Q&A with Kathy Voth

By Tamsyn Jones
Kathy Voth

Kathy Voth is one of the featured speakers at Practical Farmers of Iowa’s 2018 annual conference (Jan. 18-20, in Ames), and we’re excited she’s able to join us. Kathy publishes the popular weekly online grazing magazine, “On Pasture,” in partnership with Rachel Gilker.

For 12 years, Kathy also worked with the Bureau of Land Management, working with ranchers, university researchers and agency staff to develop solutions that help communities live sustainably in their environment. In 2004, she developed a method, based on principles of animal behavior, for teaching cows to eat weeds.

I chatted with Kathy to learn a little more about why she advocates that farmers reconsider the place of weeds in their pastures. It turns out that weeds are highly nutritious for cattle, in addition to their abundance and resiliency to weather — and that cattle, just like people, learn to eat the food they grew up seeing their mothers and elders consume.

Kathy will lead a workshop on this topic, “Teaching Cattle to Eat Weeds,” at our annual conference next month. Visit to learn more or register.

Here’s what Kathy had to say to some of my questions.

When you first developed the concept of teaching cows to eat weeds, around 2004, it was a pretty radical idea for graziers. Have you seen more buy-in to this idea over the past 13 years?

That’s not changed – it’s still a pretty radical idea. Most people think that cows eat grass, sheep eat forbs and goats browse brush. What it comes down to is animals eat what they’ve learned to eat. Our thoughts about what animals eat really restricts us and them.

It kind of goes in waves. For a while I worked really hard at getting the information out. One time, I went to Missouri and when I came back, told my dad how people had pretty much laughed at me. Then five years later, they invited me back to the same conference to talk about the same thing.

My dad said I probably shouldn’t go. Well, I went and they thought I was the greatest thing. It depends on what people are ready to think about and accept, and you just have to be there at the right time.

What do you consider a pasture weed?

Lots of people are really hung up on the idea that a weed is bad and should be killed, but a weed is just a plant out of place. I think weeds are an all-around good thing.

Even among domesticated cows, different groups eat different things. I was in Boulder County, Colorado working with a group of cows, and they were pretty much eating anything. I thought, ‘I’m going to take in every single plant they’re eating and test it.’ It was like 20 plants. One was field bindweed. They’d been eating that long before I showed up.

A lady at the testing facility said she’d really like her cows to eat field bindweed – her cows didn’t have this particular culture. There are examples of cows eating all kinds of things.

From my perspective, we have wasted way too much time and money managing weeds and should let our cows eat them. The beauty of the process is that you train one group of animals to eat one weed and watch them in pasture. They will generally try other new plants on their own, because the training process opens their eyes to the possibility that other things can be food.

Mostly, we try to manage for grass.

Why do you think that is? If cows have these potentially diverse food cultures, why do you think there’s this misconception about and focus on grass?

My theory is the reason we think cows’ [only natural diet is] grass is that, when we could start to harvest forages and store them for long-term, about the time we got mechanized enough to do that, grass was an easy thing to store. So that’s what we fed them – the more grass you have, the more you have to store.

Back in the 1750s to about 1850, people thought cows ate carrots, beans, potatoes and turnips – things we’d never think of feeding them. That just pointed out to me that cows are flexible. It’s people who are inflexible.

Have you ever heard back from anyone who was initially skeptical of teaching cows to eat weeds, but had a change of heart?

I’ve had lots of people that were really skeptical and went ahead and did it – like one guy in Montana. I think he got roped into the project by a gal he worked with at [a natural resources conservation office]. I sent him instructions, he started training and I came out to help. Sure enough, [the cows] started eating some weeds, then other weeds.

The heifers we had trained he had in a pasture divided in half with a single wire. The steers on the other side of the wire learned how to eat the weeds from the heifers – so he was very sold on it.

The guys I worked with in Bolder County, Colorado were like, fine, we’ll give you some cows to work with but we don’t want to be involved. I would do different projects with these cows, trying them on different weeds. Eventually their owners became my friends. The last year I worked with them, they had a herd of 800 cows.

I didn’t always get the same cows, and the ones I trained that went out with the herd taught others. It took about six years of sorting cows – but now they run for the weeds first.

What that guy was really impressed by was that some of the native plants were making a comeback.

If graziers already feel they’re doing a good job managing their pastures, is there still a reason they should consider training their cows to eat weeds?

If you know what you’ve got in your pasture and know what you’re managing for, you can do a good job and maybe you won’t have any issues.

The problem comes when something bad happens – it gets dry, you’re managing as best you can but you overgraze. These accidents happen often, because weather changes often. Suddenly you have more cows than you thought.

My thought with [developing this approach] was that if my cows know how to eat weeds, I don’t have to worry because weeds are very resilient. They come up during drought, so my cows will always have something to eat.

Grazing weeds is a strategy for resilience. Plus – nobody knows this – weeds are more nutritious than grass. They are basically the equivalent of alfalfa or better.

Protein is one of the limiting factors for most cattle; it’s a hard thing for most cattle to get. Weeds are very high in protein, and very digestible. That means cows can gain weight even if their pastures are lower quality.

Any time an animal has protein and dry grass, they can eat all that dry grass as well and still get an adequate diet. The protein helps them process dry food better.

You might even be able to raise more cows – you basically have 43 percent more forage if you teach your cows to eat weeds.

Does your method for teaching cows to eat weeds work just as well with older animals? For graziers who want to start doing this, would they need to plan for a longer training period?

I started with heifers because we all believe younger animals learn more quickly than older ones. But then I started training anything that anyone brought me and it always worked.

Some individuals are better weed-eaters than others, but it wasn’t breed-specific, it wasn’t age-specific. If a mother cow was a really experimental eater and would eat a lot of new things, her calves were also like that – because I got to follow some of the calves over a number of years and watch their offspring.

The bulls were really interesting, because I would teach the heifers and they would put the bull in for just a day, and he would learn really fast – I think because he was trying to impress [the cows] and fit in.

The cows have taught me a lot over the years.

How do cows compare with goats when it comes to tackling pasture weeds? For graziers who do mixed-species grazing and already integrate sheep or goats, is there still a reason for them to consider training their cows too?

Goats don’t do a better job. I did goats for a long time and did prescribed grazing with them. What I found is cows are every bit as good as goats.

The reason I would always choose cows over goats is cows are so much easier to manage and sell on a market than a goat is. It depends on where you are – I think the goat market is getting better. But building fence for goats is so hard; they’re just so smart. But a cow, I can build a one- or two-strand fence and they’ll stay in.

I tell people if you already have cows and just want to get goats to manage weeds, don’t do it. Cows can do every bit as good as goats – even on brush.

But if you think you have a market for the goat or just happen to like goats and sheep, then that’s fine. I would probably still teach the cows to eat weeds.

First I would watch what everybody is eating, because before I knew cows could eat weeds, I knew there was research showing that you could put five goats per pasture and everyone would eat well. But I’ve since found it’s maybe 2.5 goats or 3 sheep per pasture.

Once cows have been trained to eat weeds, how much active pasture management is needed? Do you still have to get rid of noxious weeds?

For example, in Montana, they have a lot of spotted knapweed and really need to reduce that. To do that, there are times you really should put your animals in a pasture. I would do that in mid-July for Montana, because at that time your other plants have senesced. You’ll have grazed your spotted knapweed before it goes to seed, even if it flowers after that, research has shown that most of the seed isn’t viable.

You could manage timing that way.

One of the reasons I really thought training cows to eat weeds would be a good thing is because, while you can put up multiple fences and force cows to eat everything, in some places that’s not viable – the landscape is too big, or water sources aren’t close enough together. My thought is a if cow is out there 24/7 and knows to eat weeds, you don’t have to do anything about it.