Join Date: Mar 2012
Location: Gainesville, Fl
I am from Florida and we are apparently selenium deficient also. I will help you out a little on your quest for answers. And it is a quest.
There are two types of Selenium.
Selenium Carbonate, which is a man made, harder to digest, and is the type that is in most horse feeds and supplements.
Selenium yeast, which is highly digestible and expensive, only in certain feeds. You can ask the company which one they use. I would use this one as a supplement if anything.
Definitely get a blood test before you start giving them selenium, then the vet should be able to prescribe how much to give. There is no way to know how much he is getting naturally without getting him tested first, and the overdose is fatal. Think, hoof sloughing off.
You can always try a good hoof supplement. I use HB15 and I can tell a noticeable difference in hooves and coat after a month or so of use.