Leafy Spurge (More will be added to this document) I have trained cows to eat this weed.

This is another Eurasia native that arrived in North America as a seed impurity around 1827. A perennial it reproduces by roots and seeds. Seeds may be viable for up to 8 years. It is commonly believed that cattle will not eat leafy spurge. However, there is anecdotal evidence to the contrary. For example, a rancher in North Dakota fenced his cattle into a small pasture with grass and leafy spurge. His plan was that once the cows had eaten all the grass. he would move them and then use an herbicide on the leafy spurge. When he returned to move the cows they had eaten all the leafy spurge. Other ranchers say that their cattle will eat it when it is not a monoculture. Terpenes appear to be the aversive toxin in the plant. Experiments with both sheep and goats have shown that protein increases their ability to consume terpene-containing foods.

Check out the Grant-Kohrs Ranch Project Report for more on this.