The use of transported cooled semen is now a big reality for breeders of most breeds of horses everywhere. The concept of transported semen is simple enough. A stallion's semen is collected and the semen is cooled and shipped to the awaiting mare. The semen is delivered the same day or the next day to the mare owner, where a veterinarian or technician inseminates the mare.

Unfortunately, reality is not as simple as the concept of shipped semen. First, equine sperm is more delicate than most other species of livestock and note that not all stallions will ship. This delicacy coupled with the complexity of the mare's reproductive cycle makes timing of artificial insemination the single most important factor in the art of transported semen.

Mare management and owner education are extremely important. The high cost of breeding, or worse yet the cost of an open mare, make the emphasis on education an even higher priority.

Mare Management
Using transported semen has tremendous benefits:

• Stallions located a substantial distance from the mare are now only a phone call away. The mare owner is finally in control of the breeding process. Of course, this has disadvantages as well.
• The lack of stress to the mare and/or foal during transport, as well as eliminating the cost of transport is a great benefit.
• Less contact with disease or reducing the possibility of injury is a huge advantage, especially when considering the well being of a show mare or foal.

Control over mare management is both an advantage and a disadvantage. This is the single key of success when using artificial insemination. The stallion manager loses all control of the entire breeding process once the semen leaves the breeding farm. The mare owner assumes all other responsibilities at this time.

Preparing the Mare
A mare owner and the veterinarian must work closely together to get the mare in foal via transported semen. It is strongly recommended that a veterinarian or semen receiving center is chosen with experience in successfully receiving semen and mare insemination.

Once this partnership has been formed between the mare owner and veterinarian or semen receiving center, a breeding soundness exam should be completed to be sure conditions of conception exist. A rectal exam of the mare's reproductive tract, as well as a uterine culture taken of barren or open mares, hormone profiles and more intensive uterine testing may be necessary. Assuming the mare passes her breeding soundness exam, it is time to begin teasing the mare.

Teasing the Mare
Most mares will come into estrus or heat every 21 days under natural conditions. Each heat lasts typically 5 to 7 days. Please note that mares are individuals and heat cycle can vary in length as well as signs.

Ideally, a mare is teased daily and her heat cycle recorded. These records can help determine a pattern of when the mare traditionally ovulates. Estrus records along with an ultrasound or rectal palpation of the mare's reproductive tract during the heat cycle can be used to estimate ovulation. If a teasing stallion is not available, ovulation must be detected solely through monitoring the developing follicle and estimating ovulation. However, some mares will produce follicles between heat cycles where pregnancy would not result. If a teasing program is not an option, then hormone therapy can encourage regular cycling. This is expensive and time-consuming, but often successful when other options are not available.

Breeding the foaling mare can be advantageous since the mare traditionally comes into heat 7 to 14 days after the birth of her foal. She then comes into heat approximately 30 days post-foaling.

Once again it is the mare owner's responsibility to determine when the mare needs to be bred and coordinate the shipment of semen from the stallion manager.

Determining When Semen is Needed
Once the mare comes into her day of heat, close attention must be paid to the mare's progression in her cycle. On average, a breeding follicle will mature at the rate of 3 to 5 mm per day. Rectal palpation or ultrasound of the mare's reproductive tract is critical. The frequency of this examination must be determined by the vet's experience and comfort level, along with the normal progression of the mare's follicles. This is where charting past heat cycles is helpful. During this examination, the size of the maturing follicle along with the tine of the follicle, uterine tone, and tone of the cervix will help to estimate ovulation. Ovulation is near when the cervix opens and softens, uterus has firm tone, and the follicle is large in diameter and soft to the touch. Stereotypically, ovulation occurs when the follicle is 45 to 55 mm in diameter and soft like a ripe grape.

As soon as estimation of ovulation is predicted, contact should be made with the stallion manager to coordinate desired semen delivery dates with the stallion's collection schedule.

Arrival of Semen
Once the semen shipment arrives, the semen must be evaluated prior to insemination of the mare. First, examine any and all paperwork that accompanies the semen. Make sure the semen that arrived is from the correct stallion, and for the correct mare! Then evaluate the semen shipment for the quality and violability. The semen should be gently warmed to 100°F and viewed under a microscope. The progressive motility of the semen is then estimated. Progressive motility is the movement of sperm in a fairly straight line. This is a sample of a good quality semen shipment. Sperm that are not moving or swimming in circles most likely won't result in pregnancy. Also any discoloring or debris in the semen should be noted and most likely be refused for insemination. If the received semen is not acceptable, the stallion manager should be contacted as soon as possible and options discussed.

Also note, that most stallion's semen will maintain viability for 48 hours after collection. Assuming the semen is viable, the mare should be inseminated as soon as possible. The mare is a far superior incubator than any man-made transport device!

Preparing Mare for Insemination
Once the semen has been evaluated and is judged to be acceptable, then the mare must be prepared for breeding with a form of mare restraint, i.e., stocks. If stocks are not available, then restraint methods such as twitching, or tranquilization may be used.

The preparation of the mare's perineal region consists of wrapping the tail, washing, rinsing and carefully drying the perineal region. The tail should be wrapped with a disposable bag or clean bandage to prevent introduction of tail hairs into the vagina.

There is no need to sterilize the perineal region of the mare prior to insemination, but the reduction of contaminating materials is desired. Strong disinfectants are not recommended since many may irritate the mare's vulva and are usually toxic to sperm. The entire region including the mare's buttocks, should be carefully washed with a mild soap or betadine solution. Be sure to rinse thoroughly with fresh water to remove any residue of soap or betadine. The entire washing procedure should be performed at least 3 times. The procedure is completed by toweling the area dry. If the towel is still dirty, repeat the process. Remember that water is detrimental to sperm.

Inseminating the Mare
After inspecting the semen and preparing the mare's perineal region, the semen is to be placed into the mare. The veterinarian or technician draws the semen into an all-plastic syringe. Some stallion's semen is very sensitive to the rubber stoppers in syringes, therefore, all-plastic syringes should always be used.

With a lubricated sleeve, the technician or vet gently enters the mare's vulva with a 21' insemination pipette cupped in their hand. Be sure that only non-spermicidal , sterile lubricant is used. The pipette is guided through the mare's vagina and into the open cervix. The cervix serves as the neck of the uterus. When ovulation time is at hand, the cervix should be open and resemble an open flower.

Once the pipette is in and through the cervix, the semen is deposited. The sleeved arm is removed with the insemination pipette and the procedure is complete.

Most semen shipments come in two insemination doses. Both doses may be used at this time or the second dose can be inseminated 12-24 hours later. Remember, most stallions' semen maintains viability for 48 hours after collection. Assuming the semen is viable, the mare should be inseminated as soon as possible.

Often upon a successful insemination, the mare may be given hormones, i.e., HCG, to hasten ovulation. Also evaluation of the mare's perineal confirmation should be assessed and caslik's suture placed as necessary. This procedure partially closes the vulva to prevent sir and/or fecal contamination to the internal genitalia.

It is recommended that the mare be palpated 24 hours after insemination to confirm ovulation. If the mare has not ovulated, re-ordering semen may be an option.

Post Ovulation
Immediately after ovulation, the mare should be put on a teasing program again. Most mares that have conceived will show little or no signs of estrus. The presence or non-existence of estrus signs is not a fool-proof indicator of pregnancy. Up to 40% of pregnant mares will show some signs of heat. Therefore it is very important to have the mare ultrasounded 15-18 days post ovulation. If the mare is not in foal, she should be returning to heat shortly and the preparation for a semen shipment can begin again.

It is recommended that the mare be kept in a teasing program until 45 days following the breeding. Fall pregnancy checks are also recommended to prepare for late gestation mare requirements, or rebreeding in the spring.

Amy Gumz, of North Judson, Indiana, owns and manages Gumz Farms, a world class breeding facility, stallion station and semen receiving/transport station. For more information about her facilities, stallions and programs, consult her website at http://www.gumzfarms.com.

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