This is the first winter I've had a cow (simmental), and my folks have 2 (with calves and are pregnant). Looks like, from a prior question, I need to get something for winter shelter. My next question is, do they need supplements to their food? They don't forage much, the field isn't that great. They are given alfalfa hay every day. I just wonder if they need something else. I've read on these boards a bit about mineral blocks and liquids. Do cows need supplements like that? And if so, what should I look for in a supplement?