ridecamp@endurance.net: Re: Re:selenium

Re: Re:selenium

Duncan Fletcher (dfletche@gte.net)
Thu, 24 Apr 1997 09:41:49 -0700

Many nutritional components can be harmful when taken in excess, including
vitamins A, C, D, iodine, sulfur, magnesium, iron, and others. Selenium is
troublesome because the amount of selenium taken up by forages can vary
widely depending on the soil. A large part of the country is deficient in
selenium, but there are areas where the levels in forages reach the toxic
level. Some of these are sizable regions, and others are hot spots in areas
that are otherwise deficient.

Insufficient selenium causes white muscle disease (nutritional myopathy).
Symptoms are weakness, impaired locomotion, difficulty in swallowing,
respiratory problems and impaired cardiac function. The body produces
abnormal muscle tissue. Selenium works in conjunction with vitamin E, and
low vitamin E levels can produce the same problem. The overall diet should
contain selenium at the level 0.1 mg/kg of diet.

Acute selenium poisoning causes blind staggers which causes apparent
bindness, perspiration, abdominal pain, colic, diarrhea, increased heart
and respiration rates and lethargy. Chronic selenium toxicity (alkalai
disease) is characterized by hair loss (particulary mane and tail) and
cracking of hooves around the coronary band. The maximum tolerable level of
selenium intake is estiamated at approximately 2.0 mg/kg of diet. Other
minerals (particularly copper) can influence the body's utilization of
selenium. Copper is fed in high selenium areas to reduce the risk of
selenium toxicity.

If you suspect a problem, a simple blood test can determine if the levels
of selenium in the horse are within a normal range. Forage can also be
tested.

I did not follow the thread that this is in reply to. I would (and do) feed
added selenium because my hay comes from Eastern Washington which is
selenium deficient. I would not, however, arbitrarily feed it as "cure"
for any other problem unless I had good reason to believe the horse was
deficient either by blood tests are a knowledge of the forage.

Duncan Fletcher
dfletche@gte.net

----------
> From: Swettboy <swettboy@ncats.net>
> To: ridecamp@endurance.net
> Subject: Re:selenium
> Date: Thursday, April 24, 1997 4:50 AM
>
> I'm confused (happens to me on occasion<g>). I have a huge book, "Feeds
> and Nutrition" by a group of experts from a university in Washington
State.
> They say selenium is toxic. They say it is especially a danger for
horses
> in states where the soil is high is selenium, mostly the rocky mt.
states.
>
>
> Peggy
>
> ----------
> > From: Karen Parker <karen.parker@stonebow.otago.ac.nz>
> > To: horseman@orednet.org
> > Subject:
> > Date: Wednesday, April 23, 1997 4:16 PM
> >
> > Hi Alex
> >
> > Another thing I thought of (Stewart did actually) is are you feeding
your
> > horse Selenium. As will get quite skitterish if they are getting
> > deficiant. You are meant to give them approx. 20ml per month. You get
it
> > as Selmit 1 or 5 from your vet and it costs around $20.00. We were
> advised
> > to give them 5ml per week so that they are always getting some, not
just
> > one big dose once a month. It was also sugested to us to give them
> Vitamin
> > E in powder form along with the selenium. This also helps to quieten
> them
> > down.
> >
> > Sorth a try. Good luck.
> >
> > Karen
> >
> > Karen Parker
> > Dunedin, Otago, New Zealand
> >

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