Many breed registries still require
breeding be done by live cover--the stallion physically covers
the mare. The actual mating process is an awesome spectacle, but
can be dangerous to the mare, stallion, and handlers when done
in hand-breeding situations. It involves the stallion mounting
the mare, inserting his penis into the mare's vagina, and
vigorously thrusting until he ejaculates, then dismounting. If
mishaps occur, the mare may not become pregnant, or injuries (to
mare, stallion, or farm personnel) might occur.
No one method for managing live cover
breeding is foolproof. Handling of the mare and stallion should
be individualized to minimize injury and optimize success.
Natural and In-Hand Breeding
There are two traditional types of natural
breeding: Pasture mating and hand-mating. In the wild, horses
breed in a relatively stable social group or harem.
Stallions in the wild will interact with a
mare (and vice versa) for hours or even days before mating.
Pasture mating most closely mimics breeding of wild,
free-roaming horses (with some exceptions). In pasture breeding,
the stallion is allowed to run with one or more mares in a
field. The stallion is responsible for determining the readiness
of each mare for mating (i.e., he is responsible for estrus
detection). In general, once a stallion gains experience in
pasture mating, he is unlikely to attempt to breed a mare that
is not in estrus. Exceptions do occur, thus some mating-related
injuries can follow.
Additionally, some stallions are quite
aggressive in pasture mating situations, and mares and foals are
at risk of injury. Due to the lack of control over this type of
situation, pasture mating is rarely practiced in today's
commercial horse breeding world. Nevertheless, there are quite a
few producers still employing this method of mating,
particularly since it reduces time and expense associated with
estrus detection and the actual mating process.
Much more common is the type of live cover
known as hand mating, which requires some form of restraint of
the mare and stallion. The amount of restraint will vary
according to individual circumstances, particularly the
temperament of the mare.
There should be a special area where the
mating takes place. This can be outdoors or indoors. When
indoors, a breeding shed designed specifically for the process
is usually used. This area should be large enough to allow ample
free movement of horses and people, have no physical
obstructions that interfere with safety, have no "blind" corners
that entrap personnel or animals, and have a flooring that
provides good footing. The ability to clean and disinfect
flooring and minimize dust is needed for a breeding shed floor.
The domesticated stallion is severely
restricted in his interaction with mares. The amount of
interaction largely depends on the management conditions at the
breeding farm. Usually, Thoroughbred breeding stallions are
confined to a paddock or stall and do not have interaction with
mares or other horses except during the teasing and mating
process. Under this type of management, some stallions might
become unruly.
In order to lesson these aggressive
tendencies, the stallion should be exercised every day. He could
be turned out in a paddock, ridden, or longed.
Warmblood or sport horse stallions
frequently compete while being used for breeding.
Stallions should be housed in large,
well-ventilated stalls with plenty of clean, fresh bedding.
There should be no sharp points in the box on which the stallion
could injure himself.
Man-Made Breeding Dates
Unfortunately, man has his own ideas of
when mares should foal. Since the early 19th Century, when Jan.
1 was declared the official birth date for Thoroughbred
foals--irrespective of their actual birth dates within that
year--horse breeders have been plagued with problems attempting
to breed mares in the winter and early spring.
For some breeds, notably the Thoroughbred,
an operational breeding season exists from Feb. 15 until the
first week of July. This man-made breeding season means that
many breeders try to get mares in foal from the middle of
February onward.
To some, it might not be clear why so much
trouble is taken in trying to breed mares before they are in
their most fertile period. The reasoning is that the two major
racing breeds (Thoroughbreds and Standardbreds) and the majority
of the breed societies use Jan. 1 as the official birth date of
every foal born that year. Therefore, a foal born on Feb. 12 and
a foal born May 12 both are considered a year old the following
Jan. 1. When these horses are sold as yearlings, having those
three extra months to mature can make a huge difference in the
price brought at auction. Having these two horses compete
against each other as 2-year-olds--or even 3-year-olds--would
probably give an advantage to the older animal that has had more
time to mature.
Artificial Lighting for Mares
Fortunately, something as simple as light
can cause the mare to cycle earlier in the season. Putting a
mare under lights is a very common means of getting her to cycle
earlier in the year.
Experience has shown that 16 hours of light
stimulus (artificial plus natural) is adequate. One means is to
provide light from 7 a.m. until 11 p.m. The extra artificial
light is best added at the end of the natural daylight period,
and works by suppressing the release of a hormone called
melatonin. An area of the brain known as the pineal gland
produces this hormone. Melatonin affects release of
gonadotrophin hormones involved in follicle production and
ovulation.
The light in the box must be bright enough
to stimulate hormone production. This means a 150-watt clear
bulb in the middle of a box/stall that measures 13 feet by 13
feet (four meters by four meters). If a strip light is used, it
should be about four feet long (1.3 meters) with a 40-watt bulb.
Care should be taken to eliminate shadows, as they can prevent a
good response. A practical method of checking that there is
sufficient light is to see if it is easy to read a newspaper
wherever you stand in the box.
There are two important points to note with
putting a mare under lights:
1) Extra lighting must be begun early.
Generally a minimum of eight to 10 weeks is needed before she is
cycling normally, thus mares should be exposed to the lighting
system by Dec. 1. This should start them cycling normally by
Feb. 15. It is not good enough to decide to put a mare under
lights and one week later expect the mare to begin cycling. This
situation often happens when a mare arrives at stud and is not
yet cycling. Unless she has already been under lights, you
cannot expect her to begin cycling in a few days just because
you put her under lights. Remember with lighting to plan ahead.
2) Mares should be in good body conditio
and well-fed when they begin extra lighting. It is preferable to
increase the mare's body condition, and this might mean extra
feeding. It is also important that the mares are healthy, on an
appropriate deworming program, and have had regular dental
checks.
In aged mares, delayed initiation of normal
cyclical ovarian activity might reduce the number of estrous
cycles during the breeding season; therefore, it is particularly
important to prevent poor body condition from occurring in such
animals. Good management can prevent prolonged anestrus.
Teasing
Teasing is a vital part of the operation of
a breeding farm. Teasing is the use of a stallion to encourage a
mare to show estrous behavior under controlled conditions. Most,
but not all, mares in heat show signs such as leaning toward the
stallion, raising their tails, squatting, "winking" (repeated
eversion) of the clitoris, and urinating. Some mares might take
several minutes before they show signs of being in heat.
At most breeding sheds, the mare will be
presented to a teaser stallion that is different from the
stallion used for mating. This is to ensure the mare is
exhibiting strong signs of estrus before the mating process is
attempted. If she is not exhibiting signs of estrus, or will not
allow the teaser stallion to mount her, breeding shed personnel
might refuse to mate her to protect the mating stallion and mare
from injury. The mare is then usually restrained by a twitch.
For quiet mares, this might be enough.
The mare's tail should be bandaged and the
vulva washed and thoroughly dried. A bandaged tail prevents tail
hairs from damaging the stallion's penis or rubbing the mare's
vulva. It is important to only use water to wash the mare and
stallion, as antiseptics can destroy the natural bacteria,
allowing more dangerous bacteria to grow.
Other preparations might include:
- Felt boots applied to the mare's hind
legs to take the force out of a kick, but boots can be
dangerous to put on and take off and some mares resent them.
- Holding up one front leg, either by
hand or using a special leg strap, which should be fitted
with a quick-release mechanism.
- Hind leg hobbles with side lines; they
prevent kicking, but can be dangerous if the mare or
stallion become entangled in them.
- Administration of a sedative to the
mare when a mare is difficult to handle because of
nervousness associated with being separated from her foal or
with being a maiden mare that is unfamiliar with the
stallion and mating process.
There is no one set method of restraining
the mare for breeding. As with many aspects of equine
reproduction, it is important to remember that each mare is an
individual and should be treated as such. Also, the body weight
and size of the stallion must be appropriate to the size and
physical development of the mare.
Your veterinarian should continue to
monitor the mare's cycle by daily rectal and ultrasound
examinations and/or teasing.
Natural Breeding: The Stallion
The stallion should be handled with a long
lead shank, but care must be taken to avoid entanglement.
Placement of a chain shank through the mouth, above the gums, or
over the bridge of the nose is commonly practiced by stallion
handlers.
A number of other methods of restraint are
also available (i.e., ear twitches, hobbles) and preferred by
some handlers. The goal is to employ the least restraint
necessary to facilitate normal stallion behavior, yet ensure the
stallion is maintained under control in the breeding shed.
Ideally, he should be allowed to approach
the mare from the left side, then brought up to the mare's
hindquarters once the mare is displaying signs of full
acceptance for mating. He is allowed to smell, taste, and
lightly nuzzle the mare. The stallion should not be allowed to
mount the mare until he has a full erection.
The mare's tail should be held out of the
way while the stallion mounts and inserts his penis into the
mare's vagina. The penis might have to be guided into the
vagina, but handling the penis should be avoided if possible.
Once the stallion has entered the mare, he
should begin to thrust vigorously. You should confirm that the
stallion ejaculates by observing tail movement (flagging) or
better still, by placing your hand lightly under the penis and
feeling the urethral pulses. (The urethra is the tube through
which the sperm passes during ejaculation.)
A safe dismount and quick separation of
stallion from mare is important for the safety of the animals
and handlers. Mares often will take a "parting shot" at the
stallion if not turned quickly with their hindquarters away from
the stallion and personnel.
Take-Home Message
Live cover breeding can be difficult and
dangerous for humans and animals. Trained personnel are
essential. The first time you watch live cover, you might be
surprised by how physical it appears. Making sure breeding
happens safely and effectively is a job requiring an enormous
amount of skill and experience. The team in the breeding shed is
often the difference between a live foal and a mating that
doesn't prove successful. Breeders should work with their
veterinarians to ensure the mare is ready and able to breed, and
that the stallion is manageable and fertile.
