This is a question that's been nagging at me for some time now. My horse gets a free choice white
salt block 24/7. We also have about 20 head of cattle, who are given the red trace mineral
blocks as often as one can be kept in front of them without them licking it into oblivion, but the trace block is still something like 98% salt. I have been told be people with decades more experience than me that offering a red trace block to horses will create kidney stones or something similar. I've heard tales from one person who actually experienced this problem, vet diagnosed stones and blamed the trace block. So, I'm a bit gun-shy about offering a trace block. I have my suspicions that the horse with the stones was also on a feed that contained trace minerals or was otherwise being over-dosed on the traces when he still licked the block for the salt. So, my question is... is it really a concern to limit a horse's access to a trace mineral block and only offer pure salt? Has anyone else heard of complications with horses that can be attributed to offering trace mineral blocks?