Advancements
in Equine Artificial Insemination
BREEDING WITH TRANSPORTED SEMEN
Today's breeding technology
provides horse owners more options than were available in the past. Artificial
insemination and semen preservation techniques make it possible to ship stallion
semen to mares nearly anywhere in the country. But success with transported semen
will depend on the careful reproductive management of both stallion and mare.
WHY
SHIP SEMEN? 
Even under the best conditions, transporting horses long distances can be stressful
and costly. Mares with foals are of special concern, since foals are particularly
vulnerable to disease and injury when exposed to new horses and environments.
Older or injured mares, or those requiring special care, may also benefit from
staying closer to home during breeding season. The ability to ship cooled semen
makes it possible for breeders to arrange matings that might otherwise be impractical
due to distance, economics or health.
GOOD CANDIDATES
Many--but not all--horses are good candidates for the use of cooled transported
semen. Both mares and stallions should be in excellent reproductive health, since
fertility problems tend to be compounded when transported semen is added to the
breeding equation.
With shipped semen, there is generally only one opportunity per cycle to breed
a mare. Problem breeders may fare better at the stud farm, where they can be
monitored and serviced at regular intervals throughout their heat cycles. Also
be aware that not every stallion's semen cools or ships well. Therefore, it is
critical for a stallion's sperm viability to be checked after a dose has been
extended and cooled for 24 to 36 hours.
This is generally the interval between collection and the time the transported
semen is placed in the mare. If you are planning to raise a registered foal,
be sure to check the association's rules regarding semen transport in advance
and follow them. While registry acceptances are growing, not every breed registry
permits the use of transported semen.
INTENSIVE MANAGEMENT
Breeding
with cooled transported semen is more management-intensive than with on-site
matings. Timing is critical. For the greatest chance of pregnancy, a mare must
be bred from 12-24 hours before ovulation to up to six hours after ovulation.
From a practical standpoint, however, once the mare has ovulated, it may be difficult
to determine whether you are still within an acceptable time frame for fertility.
Also, remember cooled stallion semen only has a shelf life of 24-48 hours.
THE MARE
Prior to breeding season,
a mare should have a full reproductive examination. A uterine biopsy and culture
may be indicated to get a clearer picture of the mare's overall reproductive
health. During breeding season, the mare should be kept where she can be teased
by a stallion on a regular basis in order to detect the onset of estrus reliably.
Once the mare comes
into heat, your equine practitioner will need to predict the onset of ovulation
accurately -- allowing time for the semen shipment to arrive. The veterinarian
will monitor the mare daily or every other day via rectal palpation and ultrasound
throughout her heat cycle to determine the appropriate time to breed her.
THE STALLION
The stallion should also be evaluated for fertility prior to the breeding season.
Semen should be tested by extending, cooling and storing it in the same way it
will be handled for shipping. Commercial extenders have different formulations.
The stallion manager or veterinarian may want to experiment to see which extenders
promote the greatest viability. Proper handling is also important. Here are some
considerations:
- An insemination
dose of cooled semen requires 1 billion progressively motile sperm cells, twice
the number used in fresh insemination doses.
- Following storage
and transport, 500 million progressively motile sperm cells would be considered
a minimum insemination dose.
- Veterinarians
and stallion managers should have the equipment to determine sperm concentrations
and motility accurately.
- Doses should
not be estimated.
- Semen extenders
should contain antibiotics to help reduce bacterial contamination and the spread
of disease.
- A high quality
shipping container is essential to semen viability; directions should be followed
exactly.
- Due to variability
between individual characteristics of each stallion's semen, the procedures for
extending, shipping, handling and insemination may vary.
- Directions from
the attending veterinarian or stallion manager should be followed precisely.
- Any semen which
remains after the mare has been bred should be checked for quality.
- Semen not used
within 48 hours should be discarded even though it may still appear to be viable.
COMMUNICATION & COOPERATION
Good communication
between stallion and mare managers is essential. Coordinating semen shipments
will take planning and cooperation.
Most stallion managers plan collection schedules so as not to overtax a stallion's
fertility or reproductive performance. Collections made 3-4 times per week will
accommodate most cooled transported semen requirements without negatively affecting
fertility, while allowing breeders to meet on-site demands as well.
The mare should be on a regular teasing and examination schedule to reliably
ascertain the proper time to breed.
This will allow planning and timely shipment of cooled semen. Many overnight
shipping services provide prompt, reliable deliveries and can reduce the need
for last-minute trips to the airport.
COSTS
Transporting semen may have some cost saving benefits. However, they can be offset
by increased management costs.
Additional costs may include:
- Special handling
and shipping charges. Board, mare care, teasing and management at a breeding
facility or clinic.
- Veterinary examinations,
palpations, ultra sound and artificial insemination charges.
CAVEATS
Pregnancy rates with transported semen are somewhat lower than with on-the-farm
breedings. This means it may take more than one cycle to get a mare successfully
in foal. The mare owner absorbs the cost of additional semen shipments, veterinary
procedures and mare care.
A TEAM EFFORT
Breeding
with cooled transported semen is a team effort requiring the expertise of qualified
professionals. The goal is to Produce a healthy foal in the most efficient, effective
way. To prevent disappointment, undue expense and loss of valuable time, you
must do your Part to ensure success.
- Understand your
responsibilities.
- Check the credentials
and references of the breeders and professionals with whom you plan to do business.
- Choose stallion
and mare management facilities and an equine reproductive specialist whom you
trust.
- Establish a good
line of communication between all parties.
- Visit the facilities
if possible Read your breeding contract carefully.
- Contact the associations
with which you are affiliated for their guidelines.
For more information,
contact the American Association of Equine Practitioners, 4070 Iron Works Pike,
Lexington, KY 40511, (606) 233-0147.
This brochure was developed by the American
Association of Equine Practitioners through a grant from Bayer Corporation.
Bayer Corporation, Agricultural Division,
Animal Health, Shawnee Mission, Kansas
66201
©1997, Bayer Corporation
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