We have our cows on winter range and are supplementing them with alfalfa. One of the 4 yr. old cows came to feed two nights ago with a very stiff gait and appeared to be trying to abort. Last night we found her down with her head back and frothing profusely out the mouth and nose. She appeared to be in pain or having spasms at times. Legs were under her except one was out in front of her. Does anyone have an opinion as to what this might be?