>When the soil is deficient in selenium, then the
horse doesn't get enough. I have my main distance horses checked every
year for selenium level as MI is very low in selenium. The
harder one works the horse, the higher the selenium level should be.
Average runs between 130 - 180. My vet tells me that Maggie's should be
around 180 or a tad higher. When her selenium level is low, then her hind
end muscles get tight and she tends to act like she is tied up although she
isn't. Very low selenium can also cause the back to be touchy,.
Selenium level is tested by taking blood. I supplement with selenium and
vitamin E since they go hand in hand.
Have your vet check some of the recent research on selenium
levels. What I've seen the last few years is that what we used to call
"average" is bordering on deficient, and that truly adequate levels are in the
range of 200 to 250 ppb.