A717
Reproduction - Artificial Insemination in Horses

Introduction: Successful artificial insemination can be summed up in the following sentence: artificial insemination is most successful when at least 500 million normal, progressively motile sperm are deposited into the mare’s uterus within 48 hours before or 6 hours after ovulation. In order to accomplish this task, great attention must be paid to the small details that make the procedure successful. It is important to remember that aside from the expense and training necessary to do a satisfactory job, the primary disadvantage of AI to other methods, such as live cover or even pasture breeding, is that a job poorly done will severely decrease the chances of getting a mare in foal.

The following is a brief explanation of the artificial insemination procedure for horses. It is important that every individual wanting to perform this procedure should first seek assistance and training from a veterinarian or a collegiate horse science program or course. If any of the following procedures are done improperly, the health and reproductive future of the mare may be greatly compromised.

Collect stallion and dilute the semen 1:1 with warm extender. If shipping, storing, or attempting to breed many mares with a single ejaculate, preparatory work should be done to determine the optimum type and dilution of extender that works best for a particular stallion. If semen is to be used fresh, the semen should be diluted with an extender that contains antibiotic and be allowed to stand for at least 15 minutes at room temperature. This gives the antibiotic an opportunity to neutralize bacteria in the semen before placement in the mare.
Wrap the mare’s tail with vet wrap or place the tail inside a palpation sleeve with tape around the base of the tail. Carefully tie the tail out of the way to help prevent contamination of the reproductive area. See Figure #1.
Wash the mare’s genital (anus and vulva) area with mild soap and water. Rinse and dry the area with paper towels. Washing the mare properly can help reduce the risk of infection in susceptible mares. In normal mares, it may help reduce the severity of postmating endometritis by reducing the amount of contaminants entering the reproductive tract. These precautions will allow the uterus to return to its prebreeding condition more quickly. See Figures #2 and 3.
Prepare the appropriate volume of extended semen for a single dose (at least 500 million motile sperm) in an all plastic syringe and place the syringe in an easily accessible pocket or on a clean tray. Make sure the syringe and pipette are accessible for single hand retrieval. The importance of this will be clear after the next step. Because veterinary disposable syringes with rubber stoppers contain a trace amount of a lubricant that is spermicidal, they should be avoided. See Figures #4 and 7.
Put a clean plastic palpation sleeve on one hand, taking care to avoid contact with any surface. This will help reduce the risk of contaminating the mare’s reproductive tract with any of the pathogens that exist on virtually any nonsterile surface. From this point on, the sleeved hand should only be allowed to contact the insemination pipette and the cleaned areas of the mare.
With the free unsleeved hand, pull the pipette from its package, touching only the receptacle end. Grasp the other end of the pipette with the sleeved hand. Again, be careful to avoid contact with any other surface.
Hold the tip of the pipette inside the palm of the sleeved hand with the thumb guarding the tip of the pipette. Attach the syringe to the pipette and draw ~ 3 mLs of air into the syringe. Later, when inseminating the mare, this 3 mLs of air will be used to help clear the pipette of semen.
Apply a bead of sterile, non-spermicidal lubricant across the knuckles of the sleeved hand. Once opened and used, the cap of the lubricant tube is contaminated. For this reason, it is common to discard a small amount of sterile lube before applying it to the knuckles. See Figure #7.
While protecting the tip of the pipette with the sleeved hand, wipe the sterile lube from the knuckles to the vulva of the mare. Make sure to close the hand, taking care to touch only the vulva with the knuckles.
While keeping the fingers together and extended, hold the tip of the pipette under a folded thumb. Then gently insert the sleeved hand through the vulva at a 45º upward angle. Care should be taken to prevent the tip of the pipette from contacting the sides of the vulva or walls of the vaginal vault. See Figure #5.
Push the sleeved hand over the pelvic rim and into the vaginal vault.

Important Note: At this point the vaginal walls should be slippery, not sticky. Experience will help to determine the difference. If the walls of the vagina feel sticky, it is likely that the cervix will be firmly closed and the mare’s uterus cannot be assumed to be physiologically prepared to receive semen. In fact, mares that tease as if they are in heat, but fail to show other physiological signs of estrus, are often found to be already pregnant.
Locate the cervix with the fingers. The cervix will feel like a fleshy lump of tissue near the front of the vaginal vault. Find the middle of the lump and gently put the index finger inside. If the cervix is open, there should be no resistance. Insert the finger completely through the lumen or opening of the cervix.
Guide the pipette along the index finger to a position where the tip of the pipette is an inch or two beyond the tip of the finger. The tip of the pipette should now be inside the uterine body.
Keeping the pipette in place, move the index finger back along the pipette until about half of index finger remains in the cervix. When the hand is moved back, the cervix should move back as well. This helps relieve the "crumpling" effect on the uterus that is sometimes caused by the pressure of the inseminator’s hand on the cervix.
Flex the pipette to a slight downward angle and slowly press the plunger to expel the semen dose into the uterus. There should not be any back pressure. The uterus makes a slight downward turn just forward of the cervix. By flexing the tip of the pipette slightly downward, the tip of the pipette is moved away from the uterine wall and allows the semen to be deposited into to the middle of the uterus.
Pull the tip of the pipette back into the palm of the hand.
Slowly withdraw the sleeved hand at a downward angle from the vaginal vault and vulva.
As the sleeved hand is withdrawn, use the other hand to close the vulva, preventing air from aspirating (sucking) into the vagina as the hand is removed. See Figure #6.