daily selenium dose?

[LBHBHNCK <LBHBHNCK@FTC-I.NET>]

Does anyone out there know how much selenium a horse should get each
day? I have been giving my mare Red Cell as a daily supplement, 2 oz a
day. Red Cell contains 0.65 mg of selenium per oz. She "mildly" tied up 
six miles into a conditioning ride the other day. I immediately loaded
her in the trailer and took her to the vet. Her bloodwork shows it was
mild, no serious damage. We know our soil is selenium deficient. She
eats local hay and is on pasture 24/7. I give her just enough sweet feed
to mix the Red cell in.
My vet is wanting to be careful about not overdosing selenium, because
that could be worse than the mild tie up. We need to find out what the
recommended daily dose is for horses. Does anyone out there know?

PS. Thanks, all of you for the recent posts about tie ups. For me, it
turned out to be timely information.

Lucie Hancock and Tamar Starofdavid.