When I first got my mineral mix the cows wouldn't touch it, and once they figured out what it was, they ate it like candy. I put about 25-40% mineral in loose salt, depending on the time of year, and usually have a blue block out as well... I don't really care how much they WANT, I just give them a reasonable amount... My mineral costs about $35 per 50 lbs, and a large portion of the cost is for the phosphorus and copper in it (we're really low on that around here)... That way I get by with about $200 in mineral per year for my herd, and they get what they need through calving/breeding time.