Equine
Reproduction
Dr.
Jack Sales, DVM
A. Special facility is generally made available.
1. Collection area should be:
a. Clean and safe with good footing.
b. Need a phantom or dummy “mare”.
c. Working area needs to be in close proximity to laboratory.
d. Restraint equipment (hobbles, twitch, etc.) should be well
organized
and handy.
e. Cleaning and
collection supplies for stallion and mare:
1.
Each stallion should have separate buckets.
2.
Artificial vagina and parts: water holding cylinder with handle,
inner removable liner, collection bottle
with filter to trap gel
fraction, thermal covering for collection
bottle.
2. Laboratory shall contain:
a. Microscope and slide warmer.
b. Incubator (100 degrees).
c. Refrigerator and freezer.
d. Autoclave.
e. Artificial vagina (see above).
f. Spectrophotometer or hemacytometer (used to check for
concentration of semen –sperm per ml.)
g. Various pipettes, measuring cylinders and test tubes, as
well as, other miscellaneous laboratory equipment.
3. Mare handling area:
a. One or two chutes.
b. Preferably in close proximity to the laboratory and
collection area.
c. Cleaning and breeding supplies for insemination process.
1. Nolvasan solution and
scrub.
2. Insemination set (sterile pipette, syringe, and ob sleeve).
3. Tail wrap.
4. Sterile KY lube.
B. Collection Procedure:
1. Have AV ready and at correct temperature (42- 45 degrees
centigrade).
2. Bring stallion into collection area, when penis is erect,
one person should be responsible for washing the penis before mounting.
Normally a mild soap and water is used such as ivory bar soap. Rinsing
thoroughly is very important to remove all
residue. (Some farms choose to use clear
water only). Make sure wash water is
warm.
3. Allow stallion to mount the phantom or live mare and the
collector should carefully, but quickly deflect the penis into the AV.
4. The stallion will thrust usually no more than 30 seconds
and then ejaculate. (Pulsating of the urethra or flagging of the tail).
5. As the stallion dismounts, slowly tilt the AV downwards
toward the collection bottle and take to laboratory for evaluation.
C. Semen evaluation procedure:
1. Separate gel fraction from sample and discard gel fraction.
2. Pour gel free fraction into warmed graduated cylinder to
check VOLUME.
3. Take sample of gel free semen to check for MOTILITY,
MORPHOLOGY AND LIVE/DEAD RATIO under microscope.
4. Take sample of gel free semen to check for CONCENTRATION
(sperm per milliliter).
5. Mare
must receive minimum of 500 million progressively motile sperm per
insemination.
6. Semen extender (milk based mixture often with antibiotics that
will make for easier handling of sperm and extend the life of the sperm cells.
7. Load warmed sterile syringe with at least 500 million
progressively motile sperm. (Example: 50% progressive motility of sample, 250
million sperm per ml. (or cc). Add extender
in equal parts, (25 ml. extender added to 25 ml. of semen). Use 8 cc or 8 ml.
per mare. Total extended volume of 50 ml. can inseminate 6 mares. (6X8=48)
D. Insemination procedure:
1. Bring mare into stocks (if foal is by side, have foal stock
also).
2. Use Nolvasan scrub to wash
perineal area. Rinse with clear water.
3. Wrap tail or have one person responsible for holding tail
out of the way.
4. Introduce warmed sterile pipette through cervix and into
vagina using sterile sleeve on arm.
5. Slowly introduce (inject) extended semen into pipette and
follow with air.
6. Go on to next mare.
A. Sending from stallion:
1. Normal collection procedure.
2. Determine insemination dose for single mare (500 million
progressively motile sperm).
3. Prepare 2 doses.
4. Place into equitainer or similar
device which will cool semen to 4-8 degrees centigrade. (This is the same as a
normal refrigerator.)
5. Ship to destination via air transport. (Usually arrives
within 24 hours.) Semen will be viable
for up to 72 hours.
B. Arriving for mare:
1. Have courier pick up from airport.
2. Preplanning should leave you with a mare that is in estrus
and ready to ovulate within 24 to 48 hours.
3. Inseminate mare with one dose immediately and one dose
within the next 24 to 48 hours depending on ovulation determination.
4. HCG (human chorionic gonadatropin)
often used to stimulate the mare to ovulate within 24 to 48 hours.
C.
Use of Frozen semen:
1. This technique is successful, but is not as successful as
using cooled, shipped semen. The technique is being perfected and may
eventually take over the shipment of cooled semen, which would allow for much
less preplanning and deadlines.
A.
Definition – the process of removing a fertilized ovum from a donor mare and
introducing it into a recipient mare’s
uterus for the recipient mare to carry to term.
B.
Procedure:
1.
Requires the synchronization of the estrous cycles of the donor mare and the
recipient mare.
a. Often accomplished by use of prostaglandin injection to
each mare at the same time during their diestrus period.
b. Each mare should come into estrus by the third day after
injection.
2. The donor mare is bred to the stallion and
7 or 8 days after she ovulates, her
uterus is flushed using
approximately 3 liters of specialized solution.
3.
The embryo is recovered using gravity (embryo settles to bottom of fluid) and
is
identified under microscope.
4. Embryo is transferred to
recipient mare, which should be approximately 7 to 8
days from ovulation.
a.
Non-surgical transfer would go through the cervix into the recipient
mare similar to
the semen insemination technique. This technique
has not proven as successful as the
surgical technique so is not
used very extensively.
b.
The surgical transfer of the embryo involves an incision in the
flank of the mare and the location of the
uterus. The embryo is
introduced into the uterus through a large
bore needle puncture
into the uterus.
c. Success rate is 65 – 75 per cent for the surgical
technique.
ASSIGNMENT (no quiz)
Please send your
answers to the following essay questions to Dr. Sales at jacksales1234@gmail.com
** Write “Repro
Lesson 9 Assignment” in the subject line of the email. Be sure to include your full name and email
address on all documents.
Please answer each question in as much detail
as possible. I am looking for an answer that shows me you are knowledgeable about
the subject matter.
1. Discuss the
advantages and disadvantages of artificial insemination programs compared to
natural breeding programs for horses.
2. Describe
important components of a breeding shed to be used in an equine artificial
insemination program.
3. Describe the
technique for preparing the artificial vagina and processing the semen to be
used in an artificial insemination program for horses.
4. Discuss the
proper insemination dose (number of spermatozoa and insemination volume),
insemination timing, and insemination technique for artificial insemination in
the mare.
5. What are the
most common reasons for performing embryo transfer in the mare?
6. Discuss the
techniques used to recover embryos from a donor mare and techniques used for
transfer to the recipient mare.
7. Discuss the
techniques most successful in the use of shipped cooled semen for artificial
insemination in the mare.