| Glacier Creek Stable is a
riding stable operating as a
concession in Rocky Mountain
National Park, outside of
Estes Park, Colorado. The
stable is allowed up to 80
horses by the National Park
Service. The company, Hi
Country Stables, has always
mixed mares and geldings in
the horse herd there. Many
horse operations do not like
to mix the sexes because of
fighting and injuries that
may result. Some owners
prefer geldings because they
believe them to be more even
tempered. The management at
Glacier Creek Stable has
found, over the last 10
summer seasons, that,
although there may be some
behavior problems associated
with mares, that mares are
the majority of their most
athletic long distance
horses. Because of the
athletic ability and
durability of the mares, the
management would like to
eliminate problems
associated with mixing the
sexes. To this end, they
tried an interesting
experiment during the summer
of 1997.
This is strictly an anecdotal
experiment on a small band of mares. For advice on your own
horses, please contact your local veterinarian. Newer
commercial equine preparations may achieve similar results.
This article is intended only as a suggestion that extraneous
behavior in mares may be suppressed by pharmaceutical means.
On June 5, 1997, at the
beginning of their busy
summer season, the Hi
Country company veterinarian
implanted 24 stable mares
with a progesterone implant.
He did three more on June
7th and a final two on July
14th for a total of 29
mares. Another company
stable had another
veterinarian implant about
10 mares the previous
summer, and although not as
carefully documented, the
people in charge of the
horses said they would
implant all the mares again
if the opportunity arose.
Another local stable had
about 4 of their mares
implanted in 1997 and
reportedly were happy with
the results.
 Dr. Patrick McCue from
Colorado State University
conferred with the local
veterinarian on optimum
dosages. Dr. McCue works
with a product called
Synovex S which has been
used as a growth hormone for
beef steers. He tested doses
of 8, 32, and 80 implant
pellets. All mares still had
standing heats. Sixteen
pellets, however, is the
usual dose and may control
some unwanted behavior, but
is not heat suppressive.
Sixteen pellets of Synovex S
releases only 3 mgm. per day
of progesterone. 50 to 100
mgm. are needed to suppress
heat. Other products
available did not seem to do
the wanted job well or at a
reasonable cost. Regumate
was the only sure way to
suppress heat. Regumate
comes in a syrup form and is
given orally on a daily
basis. It is also quite
expensive for a 21 day
cycle. The mare will come
into heat immediately when
the Regumate treatment is
discontinued. It is used by
breeding farms to help
settle mares for breeding.
Progesterone injections are
also expensive and are not
tolerated well by the mares.
The drugs DepoProvera,
Norgestamate, and
Synchromate B, that are used
to synchronize breeding
cycles in beef cattle, did
not work as desired.
The Hi Country
veterinarian followed a 3
step procedure for
implanting the mares,
treating up to five head in
a group.
1. The mare was injected
intravenously with 1.5cc. of
Rompun as a sedative.
2. When the mare
exhibited the maximum sleepy
state from the sedative, the
area of the implant was
deadened with injections of
Procaine.
3. A special injection
gun with an 8 gauge needle
was used to insert two doses
of eight progesterone
pellets subcutaneously in
the front of the right
pectoral muscle on each
animal. The second dose was
placed about a half inch
away from the first, using
the same entrance puncture.
The Hi Country
veterinarian stated that,
although the dosage will not
stop the heat cycle in the
mares, the aberrant behavior
exhibited during heat in
many mares should be reduced
or eliminated in up to 80%
of the animals. He stated
the effects should be
visible within a few days
and should continue for
approximately 150 days.
The vet made follow-up
visits the next day, and the
third day to assess any
swelling of the brisket.
Some swelling was visible in
most of the mares, but none
were unusual and all were
back to normal size within a
week. One mare had been
seemingly unaffected by the
Rompun sedative. She was
given a second Rompun
injection and still had to
be restrained with a leg
hobble and twitch. She was
sore for about three days
from fighting the
restraints. Only one other
mare required any restraint
and she was leg hobbled. She
did not fight the hobble.
Definite improvement was
noticed in at least 10 of
the mares. Mares that were
"kickers" and not
able to be used on trail
rides except as guide horses
or at the end of a line, were
much better behaved and
could be used as needed in
the line. Five of the
treated mares were shipped
from the stable before the
end of the summer. One was
shipped due to chronic
colic, but she had been
noticeably improved in her
behavior. One was shipped
for chronically lying down
on rides. And three were
shipped out for kicking and
behavior problems that had
not been significantly
improved by the implants.
The three with behavior
problems were new to this
horse herd and had not
established themselves well
in the herd pecking order. The
balance of the mares were
all well behaved, but may
have been that way anyway.
Ten of those had been with
this horse herd for years
and were usually problem
free. Five were new to the
herd but had no major
problems with the other
horses. Fewer bites and
kicks were observed than in
previous seasons. The horse
herd seemed much quieter at
night and during the day.
Attention to mares in heat
by the proud-cut geldings
was almost non-existent. In
the opinion of the Hi
Country Stable management at that time,
the procedure had been a
success and they would not
hesitate to repeat it again
another time.
|
