I have mineralyx out for all of my cattle year around. From calves to cows to bulls. The barrels are expensive but look at the ingredients list. These ingredients are not cheap. It has almost indefinite life, zero waste, and consumption is very low per head most of the time. I think in the end the cost is comparable to dry and the cattle are getting a good range of what they need.
I've heard of folks saying they couldn't afford it because consumption was too high. The way I look at it, if consumption is "high" its because they need it. Consumption varies during the year.
Mineralyx certainly is not going to harm calves, and it may do a lot of good. It is an essential part of trouble free calving, in my opinion. Much of the year in my rotational grazing system I have cows, calves, yearling heifers and bull all together. They all have access to the mineralyx barrel.
I've tried dry mineral in a feeder and ended up throwing half of it away when it turned to rock and cattle not touching it. For salt I use a $5 white block in a rubber tray set near the waterers. The cattle determine how much salt they need, not me by mixing it.
Jim