Stable talk - Veterinary Associates

Stable talk
March 2015
The importance of
selenium in a horse’s diet
Selenium is a critical dietary mineral
known as a trace element. It acts
as a powerful antioxidant and is
required for the activity of a group
of enzymes classified as glutathione
peroxidases. These enzymes are an
important component of the body’s
detoxification system and also help
protect cells against free radicals.
Though necessary for life, free
radicals, when uncontrolled, may
result in several degenerative disease
processes. Selenium functions
closely with vitamin E, another
antioxidant, to delay or prevent
certain forms of cell damage. Aside
from their role as antioxidants,
both selenium and vitamin E are
both essential for normal muscle
function. Selenium is also necessary
for the development of the acquired
immune system.
Selenium is present naturally in soil,
and as plants grow, they absorb and
incorporate the selenium. For this
reason, the selenium levels in forage
are a reflection of the selenium
levels in the soil in which they are
grown. Levels of selenium in the
soil can vary greatly, and certain
areas of New Zealand are known to
have quite low levels of selenium.
Many complete feeds contain
supplemental selenium, but for
many New Zealand horses on a diet
of predominantly hay and pasture,
deficiency is a strong possibility.
Deficiency is associated with muscle
disease, swallowing and/or suckling
difficulty, respiratory distress
and impaired heart function. Mild
deficiencies may be more difficult
to identify clinically and may be
associated with decreased immune
Equine Hospital
& Referral Centre
Providing outstanding
field and hospital care
for your horse
response or fertility issues. In horses,
selenium levels both below and
above the recommended range
can cause problems. Toxicity can
develop acutely or gradually over
time as the selenium accumulates
in the horse’s tissues. Signs of
acute toxicity may include patchy
sweating, colic, diarrhea, staggers,
and elevated heart and respiratory
rates. Chronic toxicity often affects
the hair coat and hooves. Horses
that have been exposed to too high
levels of selenium in their diet may
develop hair loss, particularly of the
mane and tail, and cracks in their
hooves or even sloughing of the
There is a relatively narrow window
between a horse’s requirement
for selenium and the toxic level.
The minimal requirement for
selenium according to the National
Research Council is 0.1 mg/kg of
dietary dry matter, which works
out to 1 milligram per day for
the average 500 kilogram horse.
Because of this narrow window
12 Sim Road, Karaka
PO Box 135 Drury, Auckland
T: 09 294 7307
E: [email protected]
Ivan Bridge
BVSc, Director
Neil Houston
BVSc, MACVSc (EqMed), Director
Lacy Kamm
Jenny Sonis
Susanne Dykgraff
Felicity Tonkin
Jeremy Bullock
BVSc (Dist) Bsc
Stable talk: March 2015
» The importance of selenium in a horse’s diet cont.
between nutritional requirement
and toxicity and the often subtle
clinical signs, it is recommended that
a sample of whole blood be taken
and submitted to the laboratory
in order to determine your horse’s
selenium levels. Results are usually
available within 24-48 hours.
These results allow you and your
veterinarian to determine if selenium
supplementation is indicated, and, if
so, the appropriate protocol to do so.
Auckland Area
As always, don’t hesitate to contact
us with any questions.
3-6 Ambassadors Tournament
at Auckland Polo Club, Clevedon
4 Barfoot and Thompson
Auckland Cup Day
at Ellerslie Racecourse
4-8 Bates National Dressage
at Manfeild Park, Feilding
5 Cross country practice day
at Papatoetoe Pony Club
7 Diamond Day in support of
Ronald McDonald House Charities
at Ellerslie Racecourse
7-8 Puhinui Horse Trial and CIC
at Puhinui Reserve, Auckland
7-8 Brinks Polo Tournament
at Auckland Polo Club, Clevedon
8 Waitemata Show Jumping
at Woodhill Sands
17-22 Farmlands New Zealand Horse
of the Year Show
at Hawke’s Bay A&P
Showgrounds, Hastings
28 Autumn Race Day
at Ellerslie Racecourse
28-29Mini One Day Event
at Waiuku Pony Club
6 Legends Raceday (Easter
at Ellerslie Racecourse
6 Open Ribbon Day
at Whitford Pony Club
10-12 Kihikihi International
Horse Trial
at Kihikihi Domain, Waipa
12 Auckland Manukau Dressage
at Clevedon A&P Showgrounds
17 Auckland Trotting Club
Premier Night
at Alexandra Park
18 Manco Easter Handicap
at Ellerslie Racecourse
19 Dressage Waitemata
at Woodhill Sands
19 Derby Day
at Pointways Pony Club
24 Auckland Trotting Club Premier
at Alexandra Park
26 Derby Day
at Meadowbank Pony Club
27 Abbots Cub/Presidents Cup
at Papatoetoe Pony Club
There have been many exciting developments recently
within the Veterinary Associates team.
Neil Houston, one of our clinic
directors, and his partner, Andrea
welcomed a lovely baby girl, Ella,
into their family at the end of
January. Darcy and Ben are already
showing off their skills as big
brothers to little Ella!!
In addition, Felicity Tonkin, one
of our associates, married her
partner, Tristan Wade, in a beautiful
ceremony in Karaka on March 1st. We
were all honored to attend, and we
wish them many years of happiness!!
Farmlands Horse of the Year 2015
Farmlands Horse of the Year Show, the largest equestrian event in the
Southern Hemisphere, is taking place this year on March 17th – 22nd at
the Hawke’s Bay A&P Showgrounds. We are so excited for all the riders
and horses that will be attending the event. We wish them all lots of
luck and would love to share stories and photos from the show on our
Facebook page.