Re: Mystery illness is tying up....

[Susan Evans Garlinghouse <suendavid@worldnet.att.net>]

Mike & Karen wrote:
> 
> Hi Susan,
> 
> Thanks for responding.  I called Nutrena and they said that selenium is
> .177 mg per pound and Vitamin E is 6 I.U.'s per pound.
> 

OK.  That's would be a sufficient level of selenium if you were feeding
a bunch of it, which you are probably not---you'd have to be feeding
probably 8-10 pounds a day to supply enough selenium.    If your hay is
grown in the Florida area, then your forage is deficient in Se
(Florida-grown hay is deficient in a lot of the minerals), and that
probably explains the majority of the deficiency in your horse.  A
working horse requires around 0.17 mg/kg of dry matter of diet, or about
1.5 mg per day.  Some horses seem to need alot more than that---Heidi
Smith has alot of experience in selenium supplementation in deficient
areas.  I think I've heard of horses requiring 4-6 mgs per day to
maintain good plasma levels.

To calculate the amount of selenium you're currently feeding, multiply
the number of pounds of Nutrena feed that you're currently feeding per
day by .90 and then multiply that by 0.177.  That's about the number of
mgs you're currently providing, and will give you an idea of how much
you need to supplement.  Toxic levels of selenium for horses starts
around 1300 mgs per day for a 900-pound horse, so don't go nuts with a
supplement, but you should definitely add some to his diet---I'd say
start with around 1.5-2 mg per day and have a blood panel to check in a
month or so.

I would definitely suggest supplementing with some vitamin E as well. 
If the Nutrena feed is only supplying 6 IU per pound, then your horse is
short by quite a bit.  The research on vitamin E in horses indicates
that while there's no particular harm in low vitamin E levels, and
therefore no "minimum" requirement per se, but there are some pretty
nifty benefits by feeding at least 1000 IU per day.  The study I like is
one in which wild horses and zebras supplemented with vitamin E prior to
capture had significantly less muscle soreness and lameness than the
animals that were not supplemented with Vit. E.  Endurance performance
in rats (which admittedly are not horses) was also 40% lower than in
rats supplemented with E.  Lots of other studies as well, all of which
argue for feeding Vit. E levels around or above 1500-2000 IU per day. 
Personally, my horses get 3000-4000 IU per day.  A safe upper limit is
around 10,000 IU per day, so don't go nuts with this either, but 10,000
IU per day is alot and you'd probably have to try hard to get into
unsafe levels.  Vit. E doesn't really cause toxicity problems like the
other fat-soluble vitamins can, but really high levels will start to
interfere with absorption of other vitamins.  

My suggestion would be to supplement your horse with a Vit E/Se
supplement, and also with a supplement that provides just vitamin E. 
Most of the combination supplements won't provide enough E without
overdoing it on the Se, so supplement the extra E by itself to get
enough.

If you have trouble figuring out the right amounts to feed in Real Life
measurements, let me know the concentration of whatever supplements you
get and I can help you with that.

Good luck!

Susan G