Commercial feed is contaminated with glyphosate, and numerous other herbicides and pesticides. If at all possible,pasture-raised,grass-fed, and grass-finished is the way to go.I have heard that it is really good, but I would have to be certain of the source. Grass-fed would make a difference, it FULLY grass fed. Mad cow was at one time transmitted when sheep carcasses were included as a protein source in feed. That's been outlawed in the US I think, but commercial feed could still be contaminated.