A mouthful of leafy spurge

Enjoying Canada thistle

Spotted knapweed was the herd favorite

Step One: Know Your Weed
Nutrition = Palatability, Toxins = Reduced Intake

Scientists at Utah State University have discovered that animals choose what to eat based on feedback from nutrients and toxins in the foods. The more nutritious a weed is, the more likely the animal is to eat it. So it's a good thing that some our nastiest weeds are just as nutritious as alfalfa!

Keep in mind that all plants contain toxins. Toxins reduce the amount an animal eats of that plant, but rarely will they kill an animal outright. Before you start, be sure you know what your toxins your plant contains so that you can safely feed it to your animals.
Scientists are also discovering that the effects of some toxins can be offset by particular nutrients (provided by supplements or other forages) or by other toxins. If you don't know what offsets what, don't worry. Simply make sure your animals have plenty of variety to choose from. With choice, they can make the right decisions.

Step Two: Choose Your Animals
Young and female, healthy and a manageable number and temperament

Younger animals are more likely to try new things than older ones and females are a good choice because they can teach their young what to eat. I suggest starting with year to a year and a half old heifers.

Your animals' nutritional state. is key to this process. You may be able to starve an animal into eating something, but the result is reduced weight gain, reduced profits, and an animal who is less likely to try other new foods. So never starve your animals! Cows I have trained have always gained weight at expected rates and suffered no harmful effects from eating weeds.

The process goes faster if the cows you are teaching have known you for a while and are accustomed to being fed by you. I work with only as many animals as I have time to feed and harvest weeds for.

You don't have to train your whole herd at once. Research shows that the trained cows will teach the untrained ones! I had first hand experience with this in 2007 when 12 trained cows trained 120 cows and calves how to eat Italian thistle in pasture. Think of that! It's ten cows trained for every one cow I worked with! If this doesn't make your life easier, I don't know what will.

Before you turn your fields into a sticky mess spraying molasses on them to get the cows to eat weeds read this:     A research experiment called "Is Molasses the Silver Bullet?" found that cows who did not have the four days of training to get them over their fear of new things ate very few weeds. In fact, the control group ate only 2 oz of distaff while trained cows ate 81 oz.

Step Three: Build on How Animals Choose What to Eat
Create positive experiences with new foods
Make the unfamiliar seem familiar
Create a good learning environment

Just like people, animals may not try new foods even if they're good for them. They're afraid of what might happen. Fortunately, an animal who has had lots of good experiences with trying new foods is less afraid to try another new things. We gave our cows good experiences by giving them new, foods like ground alfalfa and rolled grains served in black tubs. After four days of new foods twice a day, they were ready to try weeds!

Cows will also try a new food if it has a familiar flavor or smell. so I cut weeds, spray on a hint of molasses and add other familiar flavors while serving them in black tubs. Don't worry if your cows don't clean their plates the first day. Since they have no food safety labels, they try things a little at a time.

Step Four: Practice in Pasture

No creature changes unless it has to, so a little pressure is part of a good learning environment. I begin in small pastures with a mixture of both weeds and grass. This causes enough pressure so our cows don't just eat the best and leave the rest. It also gives them the time and incentive they need to learn how to harvest some of the more difficult weeds. Remember that animals will have to learn the techniques for harvesting the new forage. For example, it took cows in Marin County, California several days to figure out the best way to wrap their tongues around the very spiny Italian thistle. But once they figured it out, they got better and better with practice. Finally, never expect cows to eat solid stands of weeds. They will ALWAYS need to mix in other foods to be successful, healthy weed managers. And don't forget They'll get better and better with time.

Some Other Things to Remember

First Impressions Count: If you're not prepared to make sure your animals get a good first impression, you're not ready to start. If your animal's first experience is negative it will always eat less of the target weed, no matter what it learns later.

Stress Kills: Animals experience stress when moved to an unfamiliar location, when they can't be with those they are used to or when strange people work with them in unexpected ways. Stress increases the effects of plant toxins on the body.