Artificial Insemination (AI) – Fiction vs. Fact

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:

  1. Has the stallion been evaluated and cultured at the beginning of each breeding season?
  2. What is his past conception rate per cycle?
  3. What methods and equipment are used to determine his motility and concentration, thereby shipping a correct dosage of 1 billion progressively motile cells (PMC)?
  4. Will I receive 1 or 2 doses of 1 billion PMC in a shipment?
  5. Do you ship only on specific days? Fed X or air?
  6. Will he be available throughout the breeding season?
  7. What is the longevity of his shipped semen?
  8. Will I receive a complete report of my dose’s collections stats, including, date collected, motility, concentration, volume and extender used?
  9. What are all costs involved, outside of the actual stud fee?
  10. Are your doses a preferable less then 50ml?

the other side of the coin, the stallion manager should ask of you;

  1. What is the mare’s breeding history?
  2. Have you done a reproductive breeding soundness exam for this season, including a culture and cytology?
  3. If she was “dirty” was a resistance test done for correct and best antibiotic treatment, and was a subsequent culture and cytology done?
  4. Who is going to perform the insemination?
  5. 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 1×1, 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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