Living weed-eaters |

Living weed-eaters

Kathy Voth uses tubs to train cattle to eat knapweed. Courtesy photo/Kathy Voth

According to Kathy Voth, who has her own company, Livestock For Landscapes, cows can gain 2.2 pounds per day on forages with 16 percent protein. Cattle can meet or beat that percentage once they are trained to eat weeds like Canada, Musk, Italian, Russian, and Milk thistles, Spotted, Diffuse, and Russian knapweeds, Leafy spurge, Hoary cress (Whitetop), Kochia, Field bindweed, Pigweed, Ragweed, Curly dock, Goldenrod, Lambquarters, and Wild Licorice.

In her work teaching cattle to eat weeds, Voth has found that the plants can have better nutritional value than grass. “If they are grazed at the right time, weeds can hold their nutritional value better than grass, so why do we think of these plants as weeds? What we should be doing is looking at weeds as forage that we haven’t yet taken advantage of,” she said. “From the standpoint of raising them, they are a cheap feed source because they will always come back.”

It can be expensive to rid pastures of them. Some researchers estimate as much as $65 an acre. Figuring it takes 10 acres to graze one cow, that is the equivalent of $650 per cow per year, she explained. “So, why should a cow eat weeds?” Voth asked the producers. “The answer is because they can.”

In cattle production, Voth explained that quantity and quality of forage, and cost of forage are the limiting factors of how many cows a producer can raise, and determines how much is made. “Research has shown, on average, everybody has about a third of their pasture made up of weeds,” Voth said.

According to economist John Morley, “The average pasture is 30 percent weeds. If your cows ate just 70 percent of those weeds, you’d have 43 percent more forage.” Voth added, “(Weeds) are nutritious, available when other forages might not be, and could be part of a diverse, sustainable landscape.” In addition, the high protein forages help the rumen process lower quality plants and put on weight faster.

How stock develop their diet

“The mother is the most important factor in what a young animal will eat,” Voth said. “Cows eat what their moms ate. The reason they won’t eat certain foods is all in their head.” Voth referred to a study she conducted where lambs and their mothers were split into two groups, and the pairs were fed either Russian olive or Canadian thistle. When the two test groups were put back together, the pairs went back to whichever plant they had been eating when they were split, even with both plants present. Voth then separated the ewes from the lambs, and the lambs still ate whichever weed they were eating when they were split into groups.

Voth admits not everything in a pasture is good for the cows to eat. “There are some things they should avoid,” she said. “Flavor is a result of palatability itself. Whether they eat it or not, is not about taste.”

Voth referred to a study a professor once discussed of a photo of a steer holding a dead rabbit in its mouth. In this study, scientists were researching phosphorus-deficient soil, and the steer had picked up the dead rabbit and ate it because it was deficient in phosphorus, and the steer knew the rabbit had phosphorus in its bones. “It is interesting that animals can figure out when they are lacking something, so they will try new things,” Voth said. Taste changes over time depending on the animal’s needs, such as pregnancy or age of animal. Animals can figure these things out and mix their own diet.

Training stock to eat weeds

Producers who want to train their cattle to eat weeds will need to have an open mind, Voth said. “Your body language is very important. If you think what you’re feeding them is not good for them, they will know, and will not eat it. You have to believe what you are feeding them is good for them,” she said.

To train the cattle to eat weeds, Voth said the weeds should be green and growing, so they are nutritious. She only introduces one weed to their diet at a time. “Every single plant has some kind of toxin in it, but very few will kill an animal outright,” she explained. Voth has a website producers can refer to to find a list of plants that cattle have eaten or should eat, as well as a list of plants to not teach cattle to eat.

Voth said she likes to teach about 50 animals at a time. “It is an easy number that will match well with my resources,” she said.

The first step is to make the new seem like normal. She feeds the group morning and afternoon for four days. “I will feed them an unfamiliar, but nutritious food.” She uses a different feed for each feeding to get them used to eating something different.

Using empty lick tubs, Voth dumps in one of the unfamiliar feeds like millet, bran, rye, or beet pulp. She uses one 50 pound bag per feeding for 25 animals. Voth uses empty lick tubs because more than one cow can get her head inside at once, and they can’t see what each other is eating, which makes them more willing to try new things.

On Day 5, Voth skips the morning feeding. In the afternoon, she will clip enough of the weed she wants to introduce to loosely pack a lick tub. She puts the weeds on the bottom, and dumps the feed on top. A favorite she likes to use is wheat bran because it’s floury and coats the weeds to help get them to start eating it. It also sinks to the bottom of the tub, and they really like it, she said. “At this point, they are used to me bringing them strange things to eat, so they look at it as one more strange thing to try,” she said.

Voth continues this process and on Day 6, and Day 7, she feed the weeds alone. By then, Voth said producers need to pay attention to the target weeds in their pasture, so they can monitor when the cattle start eating it. “When they do, you are done,” she said.

Since Voth started training cattle to eat weeds in the summer of 2004, she has trained over 1,000 cows, sheep, and some of Ted Turner’s bison. She works with ranchers who are open-minded, and willing to try the process to make their operation more profitable.

For more information about training cattle to eat weeds, refer to her website: