WRANGLING ON THE RANGE #180
MARE ALWAYS IN HEAT - GELDING FRANTIC FEED TIME
FROM "HORSE AND RIDER" - DECEMBER 2011
My Thoroughbred mare, 22, seems to be in heat all the time. She
frequently squirts urine, though there are no stallions around.
The urine encrustation on her hind legs smells awful and is hard
to clean; when it does come off, it takes the hair with it. What
can I do?
HOLLY McCALL, Ontario, Canada
Applying zinc oxide to her hind end where the scalding is
occurring will help prevent this. Zinc oxide is avail able over
the counter, but you can get larger quantities, often at a better
price, through your local veterinarian.
The more difficult question is why your mare is in heat all the
time. During winter months, a high percentage of mares become
anestrus (not cycling).
Some mares will still cycle, especially if stalled under lights,
and it's certainly not abnormal for them to have regular cycles
all winter long. The normal cycle, however, is every 21 days.
Mares are usually in estrus (heat) for three to five days during
this cycle. Ovulation then occurs, after which the mare will stop
exhibiting the estrus behavior.
If your mare is truly in estrus all the time, there's something
wrong. I recommend having a veterinarian who specializes in
reproduction perform an ultrasound examination on her uterus and
ovaries. She may have a uterine infection or ovarian problem
that's causing this condition. A uterine culture will rule out
infection as the cause.
I also like to perform a thorough vaginal and vulvar examination
with a speculum to ensure there's no anatomical abnormality that
would make her more likely to develop urine scald. Many older
mares, especially Thoroughbreds, have poor vulvar conformation.
Instead of being vertical, the vulva tips, creating a shelf
effect. This allows fecal material and/or urine to pool
internally and cause infection in the uterus, which in turn can
cause abnormal cycles. There are procedures to correct a tipped
vulva, if present. Urinary infections, although not common in
mares, should also be ruled out.
Finally, there are metabolic conditions that can cause excessive
urination. Hyperadrenocorticism, also known as Cushing's disease,
is a condition of older horses that causes excessive hair growth,
laminitis, and increased drinking/urinating, as well as an
increased susceptibility to infections.
JOANNA BRONSON, DVM Bronson Veterinary Services Coldwater,
My Quarter Horse gelding has started getting extremely excited
when he's fed. He kicks his feed bucket and stamps his feet. I
haven't changed his routine. He's turned out fulltime and
receives grain once a day. What could be causing this agitated
PHIL McHANSON, Alabama
Behaviors associated with food ingestion are complex. First, with
any change in behavior during feeding time, contact your
veterinarian. He/she will be able to check your horse for any
gastrointestinal problems or nutritional deficiencies. Kicking
during feeding, especially with grain, could be a sign of
ulcer-caused pain or other gastrointestinal problems.
Horses naturally eat low-quality roughage over about 70 percent
of their day. In human-controlled settings, horses are fed two or
three times per day, in predictable patterns. Dedicated feeding
times can lead to anticipation behavior, such as moving around
faster in the stall, pawing, stall kicking, agitation, head
tossing, and other redirected behaviors. The pawing instinct is
believed to be derived from the pawing motion used by horses that
can't get to a food source that's under snow or ice. That
instinct might be a reason your horse is tipping over his bucket.
This behavior is inadvertently reinforced when a horse is fed
immediately after the behavior, especially with high-value foods
such as grains.
Once medical problems are ruled out, here are some ways of
helping decrease this behavior:
Change the feeding routine. For example, feed grain as part of
training; this allows you to use this high-value food as a reward
for things you would like to teach your horse (tricks, for
example). Consider using clicker training and feeding small
amounts of his grain that way. If all grain is fed by using a
"command-response-reward" process, your horse is less likely to
expect something for nothing and his conditioned response changes
for the better.
Eliminate grain. If you aren't working your horse hard and he has
a balanced diet, he might not need any grain at all. Or, at a
minimum, going without it for several weeks may enable him to get
away from the behavior.
Use a feed-dispensing toy. Stretching out the feeding of grain
this way may also help to eliminate the behavior.
JEANNINE BERGER, DVM, DACVB Sacramento Veterinary Behavior
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