Sue M. McDonnell, PhD


Key features of a
breeding dummy mount

Center dummy mount (learn from our mistakes!)

Center dummy mount specifications

a stallion on a dummy mount




dummy design

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Key Features of a Breeding Dummy

1. Single pedestal

2. Smooth, snug, "cool" cover

3. Sturdy, quiet when mounted

4. Ample front and side clearance

5. Ample head room

6. Especially good footing

7. Grasping grooves or "mane"

8. Angled or level

9. Other accoutrements unnecessary

Note: Self-service or adjustable dummies typically do not meet
many of these key features. Penis injuries and behavior problems are common
with self-serve dummies.

Note: Extra long dummies that allow the stallion to advance up the side
while thrusting have been associated with back and ejaculation problems,
presumably as a result of the stallion thrusting with his back curved.
Stallions should be squared up at the back of the dummy so that they don't
advance up the side.

Hofmann Center Dummy Mount: Learn
from Our Mistakes!

Our current dummy mount has evolved over the years. The base and barrel were
originally custom-fabricated with basic dimensions as now, but with a
"cut-out" groove at the left rear for the artificial vagina. A
"space age indestructible" synthetic cover was held in place with
metal snaps. The groove had turned out to be problematic, so was eliminated. The
cover quickly became tattered. It turned out to be "hot," causing rub
sores. And the metal snaps were a source of leg lacerations. It was replaced
with a custom-made leather cover. In over ten years of heavy clinic and research
use, there are only minor shoe cuts. Some horses still get rub sores.

Initially the dummy height was manually adjustable by sliding the base sleeve
up or down on the base column and securing it with pins at one of three or four
discrete heights. This required a forklift, so we rarely moved it from a tail
height of 56 inches. We have recently installed a hydraulic cylinder inside the
base pedestal, facilitating infinite automatic height increments between tail
heights of about 48 and 64 inches. If we could further improve it, we would try
some "bite" straps firmly anchored along the mid-line at the front of
the barrel for stallions to grasp onto with their teeth. We would also like to
find a disposable wrap for the tail portion of the barrel that could be changed
between stallions. The materials we have tried so far were off-putting to some

Hofmann Center Dummy Mount


Custom made steel tank, ½ inch steel, filled with sand to deaden hollow sound

Girth -68 inches (20 inches diameter) with padding and cover

Length shoulder to tail - 72 inches with padding and cover


Rectangular (8 X 12 inches) base set three feet into concrete with sleeve welded
to barrel; hydraulic cylinder with electric pump with infinite stops between 48
and 64". Best single height for QH, TB, STB, Arabian, Warmblood: 56"


Custom-made by Smucker Harness
, Narvon, PA from ¼ inch cowhide fitted
tightly over 3 inches deep dense foam padding; seams run along the dorsal and
ventral midlines, to minimize leg abrasion. End seams smooth to minimize knee
and penile abrasions and to facilitate cleaning.

Starting a Stallion on a
Dummy Mount

    Some stallions mount a dummy when initially presented,
sometimes even without a mare in the vicinity. So it is worth trying your
stallion without a mare just in case he is one of the few who take to the dummy
immediately. Other stallions require more stimulation and some training. Except
for stallions with seriously inadequate libido or physical disability, almost
all stallions can learn to mount a dummy mount of appropriate design, no matter
what their previous breeding experience may have been. Some may take several
training sessions lasting ten to twenty minutes each.


    There is no one correct way to
introduce or train a stallion to a dummy mount. The mare and stallion handling
team are critical to the success of this training. The best results can be
expected with positive encouragement of the stallion, creative positioning and
movement of the stallion and mare, and patience.

    Our usual procedure is to progress through the following
attempts until success is achieved. Each will be tried several times before
going to the next. Training sessions continue for up to 30 minutes or so, as
long as the stallion's interest can be maintained. Progress is typically
smoother if each session is ended on a positive note, before people and the
stallion become frustrated.

    1. Present the stallion to the dummy mount without
a mare, on the chance that he is one who will mount immediately, and also to
allow him to investigate the dummy and surround.

    2. Stimulate the stallion to readiness to mount using
a stimulus mare at a short distance from the dummy; when he seems ready to mount
direct the stallion to the dummy.

    3. Place the mare alongside the dummy and tease the
stallion across the rear of the dummy, encouraging him to mount the dummy.

    4. Allow the stallion to mount the mare for semen
collection a few times near the dummy to get the stallion comfortable with
breeding in that location, then remove the mare and try as in steps 1 or 2
above. Some stallions are quick to learn that if they don't mount the dummy you
will eventually let them mount the mare.

    5. Lead the mare with the stallion following/teasing
from behind the dummy, diverting the mare at the last moment to the side and
bumping the stallion's chest into the rear of the dummy.

Training Tips

· Estrous mare urine applied to the dummy mount can encourage a
stallion to mount.

· Bumping the stallion's chest against the dummy may stimulate a
"reflex mount."

· Impairing the stallion's vision with blinkers or blinders can sometimes
facilitate mounting.

· If the stallion seems ready to mount, but hesitates, stimulate the penis
by placing the artificial vagina or warm compresses on the glans while the
stallion is teasing.

· Getting the artificial vagina in place as calmly and quickly as possible
can keep the disorganized stallion mounted and thrusting.

· The first couple mounts may be awkward and poorly oriented, but one
ejaculation occurs, subsequent mounts are usually much improved.

· Once the stallion has successfully mounted and ejaculated on the dummy a
few times, the mare or other special procedures used during training may be
gradually eliminated.

· Take care not to remove the artificial vagina abruptly while the glans
penis is flared or to rush the stallion to dismount after ejaculation.

· Set aside time specifically for training, as opposed to waiting until the
moment you need semen. This will typically reduce the frustration for everyone,
and actually facilitate more efficient progress. Simply not having to worry
about obtaining usable semen during training greatly reduces the frustration and
gives you the option of putting the horse away without mounting.

· Should the people or the horse become frustrated, it may be more efficient
to have expert consultation; often success can be achieved in a few minutes of a
fresh look by an experienced reproductive behavior expert or someone who has
done this many times.

Some Common Pitfalls

· Sub-optimal dummy mounts can be particularly off-putting for
a beginner. It may be worth taking the stallion to a better dummy for initial
training. Once a stallion learns the concept of a dummy mount, it may be easier
to return to a sub-optimal dummy.

· Rub sores on the inside of the knees can cause the stallion to "stand
up" with his front feet on top of the dummy. He'll appear reluctant to
mount or to "lock in."

· Rushing the stallion to dismount can create subsequent reluctance to mount
or ejaculate.

· Enforcing perfection on the first try may be counter-productive. Many
stallions start out mounting sideways. If safe, it might be best to accommodate
imperfection until the stallion learns the basics concepts.

From "The Horse" April 2002:

Breeding Dummy Design

by: Sue
McDonnell, PhD, Certified AAB

We have a Quarter Horse stallion that we will be starting in a
shipped semen program this year. All of us--the stallion, our
veterinarian, and our farm personnel--are new at collecting semen. We are
in the planning stages for our breeding room and trying to make decisions
on a dummy mount. Our vet said that you recently gave a talk on dummy
mounts at the American Association of Equine Practitioners meeting and
would be able to advise us on dimensions for our dummy mount. We have only
this one stallion, at least for the first year. He is 15.2, with a very
long body for a Quarter Horse, and he is very athletic. We would
appreciate any recommendations on how big we should make the dummy for
this stallion. Cathy

 For fit of a breeding dummy, consider:

  • The dummy's barrel length from shoulder to tail;
  • The dummy's height at the tail; and
  • The girth of the barrel, or barrel diameter.

For almost all stallions, a barrel length (from front to tail) of 60
inches is ample. It doesn't hurt for it to be longer, but it is not
needed. You want to keep your stallion nicely squared up at the back of
the dummy as he would be with a mare, rather than advancing up the side of
the dummy.

Concerning girth, for Quarter Horse stallions, a barrel diameter of 20
inches almost always works. A good starting height for a stallion of 15.2
hands would be about 55-58 inches from the floor to the top of the barrel
at the tail for a level dummy, and an inch or so lower if the dummy body
is angled. Since your horse is long in the body, you might want to go a
bit higher than average. If he is athletic, it is probably better to go on
the higher rather than the lower range. This will stretch him out and
encourage him to stay coupled up squarely at the rear rather than
advancing up the side of the dummy as he thrusts.

Another big design question is whether to buy or build a dummy with one
fixed height or to go for an adjustable-height dummy. Like almost
everything, each has advantages and disadvantages.

One of the most important features of a dummy is sturdy, solid
construction. Whenever you make it adjustable, you run the risk of
introducing jiggle and rattle that can distract certain stallions that
would otherwise do well with a more solid, quiet design. For farms with
plans for one breed with fairly uniform height, it's often most practical
to choose one fixed-height dummy, and to design it on the high side. If
for some horses you need it lower, the height can be effectively reduced
by placing thick mats, such as cocoa mats, around the dummy for the
stallion to stand on.

Breeding Dummy Size
Breeding Phantom diagram