It's extremely important that livestock get enough salt and minerals in their diet. In the Willamette Valley you have to be especially careful of Selenium and Magnesium defficiencies. A condition called Grass Tetany will kill cattle if they don't have enough magnesium in their diet.
Magnesium defficiency often hurts the best cows and happens in late winter to early spring when the grass is growing but still inmature and without nutrients and minerals.
Lorin and I have been around agriculture our whole lives. We're happy to be part of the family farm.