A Mare Owner’s Guide to the Use of Transported Semen

Imagine the possibilities.

Your dream stallion is thousands of miles away, your mare is safe and sound in your barn at home and by using transported semen she can be bred without ever leaving the farm. The possibilities are endless, the technology is here, but to be successful you must prepare yourself and your mare.

Start by calling your veterinarian and explain that you would like to breed your mare by transported semen. You will need the skills of a veterinarian who handles reproductive work on horses. Your veterinarian will need to be able to determine the best time to order semen, to inseminate your mare and to determine her pregnancy status after breeding. Your veterinarian will need to be able to come to your farm several times during the breeding process. Be sure to ask if weekends are a problem. If your veterinarian is not comfortable handling your mares’ breeding you may wish to take her to a veterinary clinic or a breeding farm where there is skilled help available.

Here’s the fun part, selecting a stallion for your dream foal. But, before you make a commitment ask a few questions. Ask the stallion manager if they offer transported semen. Ask what days of the week semen shipments are available and how much advance notice they will need for a shipment. Ask how the shipments are sent (UPS, Fed Ex, etc.) and also ask if Same Day Service is available via air courier and which airlines do they use. Be sure to ask the costs for collection, shipping and airport transportation. Find out if the breeder provides a container for shipping and if a deposit is required. Lastly, ask how many doses of semen you can expect per shipment and will the stallion be available during the entire breeding season or will he be unavailable due to horse shows or exhibitions.

Once you have made your selection, you will need to fill out your breeding contract, and make any required deposits, stud fee payments and shipping prepayments. Some breeds require special permits to be purchased in advance. Be sure to read your contract carefully and note any special requirements for the use of transported semen. Some farms have contractual clauses and will void a live foal guarantee if these are not followed.

Now, take a good look at your mare. She should be in good weight, not too fat and not too thin. I like mine “pleasantly plump”. Before you breed her have your veterinarian do a thorough reproductive check-up including a rectal palpation with ultrasound, speculum examination and a uterine culture. Your veterinarian may recommend a uterine biopsy if your mare has a history of infertility. Don’t forget to have her teeth checked, her vaccinations and deworming updated and her feet trimmed. Think in terms of making her the best possible mother, healthy, sound and fertile.

OK, you’ve done your homework and now it’s time to make it work. You will need to get your mare in heat. One way is to tease your mare daily with a teaser stallion or gelding and wait for her to come in heat. A second way is to give an injection of prostaglandin. Most mares will come into heat within 2-4 days after the injection but your must be cycling or she won’t respond to the injection. A third way is to “program” your mare by giving the drug Regumate (a liquid hormone) once daily for 15 days. On the 15th day you administer an injection of prostaglandin. Most mares are in heat on the 19th day and ready to breed between day 21 and 23. By using this program you can literally pick a date on the calendar that you would like to breed. It is especially helpful in cases where the stallion will be unavailable due to shows or exhibitions. I prefer to start the Regumate on a Thursday. She will be ready to start follicle checks on the 19th day which will be a Monday. She should be ready to breed on the 21st to 23rd day which will be Wednesday to Friday. This avoids the problems that come with weekend semen shipments. For mares that are coming to the clinic for breeding she should arrive on a Monday and be ready to go home by Saturday. Using this program minimizes the owners’ expenses for repeated examinations, inseminations and boarding.

If your mare is foaling, you can expect her to be in foal heat approximately 9 days after foaling and again approximately 30 days after foaling. Foal heat breeding is controversial at best. I use foal heats provided that the delivery was normal with no complications, the placenta was passed intact within 60 minutes and there has been no abnormal vaginal discharge. I normally examine mares on day 7 after foaling to see if she has any signs of bruising or infection. If she has any signs of bruising or infection, I recommend waiting for her 30 day heat.

Once your mare is in heat, your veterinarian will need to determine the best time to order semen. Most mares with a 40 mm follicle and a grade 4 cervix will be ready to breed. I normally will give the mare an injection of HCG (Human Chorionic Gonadotropin) or Deslorelin on the day I order semen. The semen will arrive the next morning in most cases. The mare is inseminated on the day the semen arrives and then examined 24 hours later to be sure that she has ovulated and is not retaining fluid. Some mars require treatment for fluid retention. If she is still holding her follicle a second dose of semen is inseminated. It is important that the veterinarian check the mare 24 hours after her last breeding, if she has not ovulated you will need to order more semen. Once she has ovulated mark your calendar for a pregnancy check 16 days later. Be sure to return the container to the breeder as soon as you have removed your last dose of semen.

Do’s and Don’ts

• Do use the semen the same day it arrives. This ensures the maximum numbers of live sperm in the mare. Some breeding contracts require the mare to be inseminated the same day or all guarantees are void.
• Do not attempt to store the semen. Use the semen immediately with a second dose (if provided) 24 hours later. The semen gradually dies with prolonged storage and bacterial numbers increase. Never put old semen in your mare. If the mare doesn’t ovulate, call for another, fresh semen shipment.
• Do use the entire dose provided by the breeder. Most breeders will ship 1 billion progressively motile spermatozoa to compensate for the losses due to cooling. A minimum dose should not go below 500 million for transport.
• Do not split the dose to breed more than one mare. You may decrease the sperm numbers so low that neither mare will conceive.
• Do send the container back to the breeder as soon as the last dose is removed. Remember that there are other customers waiting for semen shipments and you might be one of them. Be sure to send all of the container components back to the breeder.
• Do not preheat or warm the semen. The semen has been slowly cooled to 4 degrees C. Rapid warming may shock the semen and damage it. The mare is the best warmer.
• Do not open the container before your veterinarian arrives to inseminate the mare. The container is self-cooling and every time you open it the container looses cooling power.

Mare Owner’s Checklist

1. Contact veterinarian to handle the breeding.
2. Schedule reproductive examination of the mare. (to be done day 7 after foaling if pregnant)
   Rectal palpation and ultrasound
   Speculum examination
   Uterine Culture and cytology
   Uterine biopsy (infertile mares)
3. Preventive health care
   Vaccinations
   Deworming
   Dental Care
   Hoof Care
   Coggins Test
4. Begin teasing program or “program” mare with Regumate
5. When the mare is in heat the veterinarian starts follicle checks
   Order semen when follicle is ready and administer HCG or Desorelin
   Inseminate mare on the day semen arrives
   Veterinarian rechecks mare 24 hours later. If she has ovulated schedule a pregnancy check. If she has not ovulated administer the second dose of semen and recheck again in 24 hours. If ovulation has still not occurred order a second shipment of semen. Treat fluid retention if needed.
   Be sure the shipping container has been returned.
6. Ultrasound for pregnancy by day 16
7. Notify breeder of results

If pregnant… Celebrate
If not pregnant …go back to #5 and try again
If not pregnant after 2 cycles… repeat #2