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Artificial
Insemination
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.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
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, ultrasound 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.