MU Vets Seeing More Horses
with Nutritional Issues This Year
-Expert warns selenium
poisoning, vitamin E deficiency a result of last year's drought,
Spotlight on Science (courtesy of KFRU)
much of the Midwest has recovered from the drought that parched
the area last year, horses are continuing to experience effects
from the hot dry summer of 2006. Due to a bad hay crop, University
of Missouri-Columbia veterinarians are reporting an increased
number of horses with chronic selenosis and vitamin E deficiency,
problems that can be fatal.
"Last year's drought meant
that Missouri's hay crop, which is usually balanced very well
for a horse's nutrition, was much poorer than usual,"
said Philip Johnson, professor of veterinary medicine and
surgery. "Because of the poor Missouri hay crop, horse
owners imported hay from other states nearby and possibly
fed their horses hay that was too high in selenium. This can
have very grave consequences for horses. Owners also may have
fed their horses poor quality hay from Missouri or other places,
which led to deficiencies in vitamin E, another very dangerous
problem for horses."
Selenium is a naturally occurring element
and is an essential part of horse diets. However, too much
or too little can create problems for a horse. When chronic
selenosis, or selenium poisoning, occurs from eating too much
of the element, horses can lose the hair in the mane and tail
and develop a form of laminitis, a painful condition that
affects the hoof. If left untreated for too long, a horse
with chronic selenosis may require euthanasia as a result
of severe laminitis.
Johnson said that the amount of selenium
in hay can vary by county throughout the nation, but that
Missouri hay typically has just the right amount of the essential
element. For a small fee, horse owners can have their hay
tested to determine if it has the right amount of selenium
In addition, hay that is not fresh can
lack vitamin E, an antioxidant which is important for nerve
health in a horse. Some horse owners unknowingly compensate
for this deficiency by feeding their animals with nutritional
supplements. Those horses that suffer from a vitamin E deficiency
typically show symptoms that include weakness, loss of weight,
trembling and changes in the retina at the back of the eyeball.
A quick blood test can determine if the animal is suffering
from a vitamin E deficiency. Johnson recommends that horse
owners who imported hay from unknown sources last year either
have the hay tested or keep a close watch on their horses.
Horses that do not have access to green grass and that are
being fed old yellow hay are at risk.
"Usually, by the time the horse
is showing symptoms of either problem, it may be too late
to reverse the disease completely," Johnson said. "However,
if a horse owner has other horses that are feeding from the
same food source, it's important to have those animals treated
before the damage is permanent."
Craig Roberts, a professor of agronomy
in the College of Agriculture, Food and Natural Resources
at MU, says the quantity of this year's hay crop will be down
50 percent to 75 percent from normal, but the nutritional
value will be good.
"Last year, we had the drought,
which affected both the quantity and the quality of the hay,"
Roberts said. "This year, we had a late freeze, which
mainly affects the yield. Overall, we will be down, but the
drought last year was far worse."
to News and Events home