Details for Cattle Production, Equestrian

I live in East Texas and this is our first year with farm animals. We have 13 acres, one yearling horse, a cow, and a 10 month old bull. I am trying to see how much hay we will need for the winter. They are free grazing on about 10 acres total. When we bought our property last year the winter didn’t kill the grass and our neighbor who is mainly a cattle farmer had his animals on his pasture and only supplied 1 round bale to all his cattle per day. He has easily 20 plus head eating the one bale. He has them on about 15 acres or so. I’m trying to kind of judge based off of what he was doing but don’t want to do anything wrong. We absolutely love our animals and don’t want to over feed or under feed them. I am also wondering what kind of hay I should purchase for them. Should I purchase coastal hay for the horse and cow hay for the cows or should I just feed them all the coastal hay even though it’s more expensive? We are so lost here, so any advice is greatly appreciated.