Calleigh did have too much grass one time and she did throw up. I only let her have grass in my yard where I know there are NO pesticides. That would be something for everyone to watch out for. People don't always put the little pesticide flags up. It could be very harmful to the "little cows."
I feel lettuce is perhaps better for them. She loves that, in fact she's having some right now while I'm having my lunch.