I wouldnt think that saltmixes would be to blame for livestock deaths. On occasion a bad batch comes through ( all brands are susceptable to this ). Various brands of salt mixes contain varying levels of elements, which may make different mixes better suited for different environments. Aside from that I would just pick a brand and stick with it.

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(' )< David >( ')

"The world is headed for mutiny when all we want is unity" Scott Stapp, Creed