Artificial
Insemination (AI)
Fiction vs. Fact
By Karen Berk
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The term,
Artificial Insemination, or often referred to by it's initials "AI," has become
a catch all phrase for most phases of reproduction not done by live cover. In
definition, it is the process of introducing live, prepared semen, into the
uterus, by means of a pipette and syringe, by a veterinarian or technician, for
the purpose of fertilizing an ova. This process is done vaginally, with the
pipette passing through the cervix. The prepared dose of semen is deposited,
and then makes it's way to the ova fossa, the site of conception. When
utilizing a fertile stallion, and a reproductively sound mare, both under
proper and knowledgeable breeding management, conception rates are higher then
live cover.
Why then is a large portion of the breeding public
frustrated, misinformed, or shipped semen illiterate? Luckily we are beginning
to see a great deal more information, being published, discussed on dedicated
chat sites, and clinics and lectures, focusing on reproduction technology.
Aggressively educating oneself is one key to success if investing in a
breeding program. Wether you are, contemplating breeding your one and only pet
mare, a hobby enthusiast, or serious horse breeding business, it is an
investment in time and capitol, not to mention sweat equity. The next key is
utilizing proper procedures. This applies not only to yourself, but feeling
confident about your prospective stallion's breeding management. Never be
concerned about asking questions. These should include;
- Has the stallion
been evaluated and cultured at the beginning of each breeding
season?
- What is his past
conception rate per cycle?
- What methods and
equipment are used to determine his motility and concentration, thereby
shipping a correct dosage of 1 billion progressively motile cells
(PMC)?
- Will I receive 1 or
2 doses of 1 billion PMC in a shipment?
- Do you ship only on
specific days? Fed X or air?
- Will he be available
throughout the breeding season?
- What is the
longevity of his shipped semen?
- Will I receive a
complete report of my dose's collections stats, including, date collected,
motility, concentration, volume and extender used?
- What are all costs
involved, outside of the actual stud fee?
- Are your doses a
preferable less then 50ml?
the other side of the coin, the
stallion manager should ask of you;
- What is the mare's
breeding history?
- Have you done a
reproductive breeding soundness exam for this season, including a culture and
cytology?
- If she was "dirty"
was a resistance test done for correct and best antibiotic treatment, and was a
subsequent culture and cytology done?
- Who is going to
perform the insemination?
- What method will you
be utilizing to determine ordering semen; teasing, palpation, ultrasound, or a
combination?
Reasons for these questions brings
us to the fiction and fact aspect of our subject.
FICTION, it only
take one sperm cell to impregnate a mare.
FACT, live cover needs 100
million progressively motile cells, on farm AI takes between 300 and 500
million, and shipped requires 1 BILLION PROGRESSIVELY MOTILE CELLS, for
conception. These are internationally accepted figures.
FICTION,
high motility equals high fertility.
FACT, although no one would
knock high motility and or concentration, it is not a necessity for conception
in a shipped semen program. You need to be able to deduce both in order to get
a 1 billion PMC dose, and this should be done by a phase contrast microscope,
with a heated stage, and some form of sperm counter. So it is the final dose
that counts, not the motility. I have a number of stallions we collect that
have never been above 60%, with a 100 % conception rate for years. The formula
is: volume x concentration x motility = # of progressively motile cells
available. Let's look at this under a couple of different scenarios.
Our first stallion has given us a collection of 50 ml of gel free
semen. His concentration is 200 million per ml, and his motility is 80%. We
take 50 x 200 million x 8o% which equals 8 billion cells. Knowing we are
shipping 1 billion per dose, we know we have 8 doses available. We divide the
50mls by 8 rounding off to 6.5 ml of semen per dose, adding 33 ml extender (5
to 1), gives us a prepared dose of approximately 40 ml. Mares in research
programs, have shown lower conception rates when inseminated with more than 50
ml at a time.
Our second stallion's collection netted us a nearly
identical 50 ml of gel free ejaculate, with a concentration of 200 million per
ml, but his motility is 35 %. Big difference. But is this stallion any less
fertile using correct methods of preparing his semen? We again multiply 50 x
200, but then x 35%. It equals 3.5 billion total cells. This is enough for 3
doses. Our problem now lies in the fact that to properly extend this, I would
need to add 14.8 ml of raw semen to 75 ml extender, making the dose a whopping
90 ml. Quite a bit over our 50 ml. limit. We have 2 choices. First, divide into
two 45 ml packets, with instructions to inseminate 4 hours apart, letting the
mare owner know that two packs equal 1 dose. Second choice, and more
preferable, is utilizing a centrifuge, spin the semen down, extended 1x1, as
one would to freeze semen, and re-hydrate your sperm pellet with 40 ml
extender, giving you a strong adequate dose. One must also figure in cell loss
when centrifuging. I would finish with 2 doses, of this ejaculate of 3.5 doses,
utilizing this procedure.
Although our first stallion makes life easier
for his manager, there is no difference in the quality and potential fertility
of a shipment from either stallion. Additionally, either could lose an
additional 50 percent of the motility, during shipping, that they began with,
and still be totally viable. My personal best was a pregnancy, and resulting
foal, out of 10% motility which arrived at 4%, shipped 2200 miles.
I can
not stress enough the importance of making certain the stallion you choose for
a shipped semen program, has an adequate lab, and technicians who do not cut
corners. I would prefer to be told that I could not receive semen because the
stallion produced 2 doses that day and I was third on the list, than to be
shipped an insufficient amount, less then 1 billion cells, that compromised any
efficiency of the insemination. This is a most common problem in communication
and understanding between management and mare owner, and an area where time and
money are forfeit.
FICTION, keep breeding till she is pregnant,
or, the more you breed, the better your chance.
FACT, mares set up a
normal inflammatory response to seminal fluids. A healthy normal uterus flushes
itself, to be rid of excess fluid. In older mares, the uterus loses it's
natural gravity causing tilt, making it a site of infection and "pooling". For
this reason, your vet might wish to flush your mare, 4 to 6 hours post
insemination. All viable semen will have arrived at the ova fossa, site of
conception, within 4 hours. Any cells remaining in the uterine body, are not
viable, and should be flushed. An injection of Oxytocin is also indicated, to
begin the contractions that flush the uterus. Research has recently proven that
the uterus also builds antibodies against future semen, wether deposited
naturally or through artificial insemination. It actually build an immune
system to the semen after 3 cycles. Therefore, if you have bred through 3
cycles, are certain through diagnostic tests, that your mare is reproductively
clean and sound, and the stallion's collection and shipment methods are
correct, stop breeding. You will be wasting money at this point. Give the mare
2 to 3 cycles off. This then also applies to breeding live cover or
inseminating a mare more than twice during her cycle. Excess coverage of the
mare sharply decreases chance of conception. You should by means of palpation
or ultrasound, be able to determine ovulation, and should not order semen
before the mare has a 35 follicle. Try to inseminate as close to ovulation as
possible.
FICTION, discard semen if it arrives the morning the
mare ovulates.
FACT, inseminating within hours of ovulation is an
excellent time. Arabian mares tend to conceive better with post ovulation
insemination. There is a window though, and conception rates decline after 8
hours. Most mares ovulate between 4AM and 10AM.
There are no set cost
to shipped semen and AI. Make certain you have asked your questions, are
satisfied with the answers, and have it as part of your contract or agreement.
Many stallion owners include shipped semen and it's cost in the stud fee. If an
outside veterinarian or lab is used, and there is an additional cost to you, do
not be shy about contacting them for answers. Always discuss your plan with
your own veterinarian, and set up a program for pre breeding reproductive
health exam, and check out his/her background and availability as to artificial
insemination, procedure, and disposables. It is preferable to use non
spermicidal syringes and lubricant. This would give him/her time to prepare.
Know the charges you may incur for the exam, flush, insemination, ultrasounds,
etc. Being surprised is never pleasant.
Fiction belongs on your
bookshelf. As an informed breeder utilizing the outstanding technologies
available to us, the fact is, success is an odds on favorite.
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