angus9259 wrote:I have not proven to myself minerals are of any value. Cattle seemed healthy with them - they seemed healthy without. They have issues with them, they have issues without.
I put them out because smart people tell me I should but I have no proof they are right.
I appreciate that observation. It is impractical to conduct our own research to determine what benefits our livestock. Therefore, we rely on the state of the art practices that "smart" people tell us to use.
I suspect there is profound value in using minerals. Obviously, you would not doubt the years of evidence associated with the occurrence of grass tetany. I also think copper, selenium and most of the other elements are beneficial for physiology and reproduction.
I think your point is a demonstration of the impracticality of proving to yourself that the minerals have a specific observable effect.