Transported Semen
Darrell W. Dalton DVM

The Process
Before the breeding season even begins there are a number of steps that must be completed. Obviously, the mare owner must select a stallion that they wish to breed their mare to, and contact must be made to work out the logistics. All stud fees, shipping fees, collection fees, and “whatever” fees must be agreed upon and contracts signed prior to the breeding season. You must establish when the stallion will be available to ship, what days he will ship, how he will ship, and whether there is a shipping company available to meet all of these conditions, both for the mare and for the stallion. Also it must be established how many shipments will be made to the mare, and over how many cycles. All breed requirements must also be met in order to get a foal that we can register. Some breeds are very open regarding transported semen, and some are very restrictive. Be sure that you are familiar with your breed association’s regulations. For example: some registries require that a veterinarian be involved in the insemination of the mare. Once you have completed all of your pre-breeding season homework, you are ready to begin.

Darrell Dalton

Dr. Darrell Dalton was born and raised in Calgary, attended the University of Alberta for Pre-vet and graduated from WCVM in 1980. He established a Standardbred race horse practice in Calgary and Edmonton for six years, then moved to Red Deer and started a pleasure horse practice. Dr. Dalton gained a special interest in equine reproduction, especially the transported semen system, and he has taught the Horse Breeders School at Olds College with Les Burwash since the early 90's. He is actively involved in the Alberta Veterinary Medical Association as Vice President for 2007. Dr. Dalton is currently on medical leave from practice, and looking to return in early 2007.

The initiation of a transported semen event begins with a phone call. The stallion manager is called on the first day of the mare’s heat to let him know that an order for semen will be coming shortly. The first day that a mare is detected in heat, the veterinarian is also called to arrange for palpations or ultrasounds to determine follicle size and development. Typically a mare is palpated daily until she reaches a follicle size of 30-35 mm, then semen is ordered. Depending on the shipping schedule of the stallion, arrangements are made for the semen to be collected and shipped to the mare. Once the semen is received, the first dose is deposited in the uterus of the mare, and if a second dose has been sent, it is then stored in the fridge for use the next day if required. Hopefully when the semen arrives, the mare has not ovulated, but does so by the next day. Often we will decide to give the mare Human Chorionic Gonadotropin or a synthetic analog to encourage her to ovulate sooner. Ideally we want ovulation and insemination to occur as close together as possible.

After the mare is bred, it is important to fill out all paperwork that is required by the registry, and send it to the appropriate place. If a disposable shipper has been used, it may or may not be necessary to return it, but if an Equitainer has been used, it is imperative that it and all of the pieces be returned as soon as possible. A large number of stud farms will charge a late fee for Equitainers that are not returned within 3 working days of being sent. Be sure to send back to the US by ‘air’ and not by ground, or you will pay a lot in late fees!!

From the Stallion Owner’s Perspective
Transported semen has been a great boost to the availability of mares for stallions anywhere in the world. Within North America in most locations it is possible to get semen to a mare within 24 hours of collection. The stallion is therefore able to breed a greater number of mares, without the necessity of having to have facilities to house them at the stud farm. Some stallion handlers think that not having mares at the farm reduces their income because they do not get paid for mare care. This is false, in that if the mare is not at the stud farm, the feed, labour, and capital costs and upkeep of facilities is greatly reduced. Most stud farms do not charge enough for mare care to even cover their actual costs. Unfortunately, because some stallion owners feel that they are loosing out on mare care fees, they must make it back in “whatever” fees, and they charge for every service that they can. It is important to state all fees prior to the breeding season on the contract so that there are no surprises for the mare owner that will lead to conflict.
It is the stallion owner’s responsibility to make sure that he is providing viable semen to the mare owner. Proper collection and evaluation equipment must be purchased or be available to ensure the quality of the semen being sent. Equipment such as a sperm counter, incubator, and a microscope are a must! It is also important that the stallion manager be educated in the proper evaluation, handling, and shipping of equine semen. Another owner’s responsibility is to ensure that the stallion is available to ship semen. Being at a horse show for a week, with mares to be bred at home, or semen to be shipped, is not being responsible!

Prior to the breeding season, each stallion offered for shipping should have his semen evaluated, and his “shipping window” determined. This is done by collecting the stallion and extending the semen in a number of different extenders, then determining which extender gives the greatest longevity to the semen. The amount of time it takes for the semen motility to reach 50% of what it was at collection is the shipping window for that stallion. Most stallions will have a shipping window over 48 hours, but some will not. Some stallions will also have poor semen progressive motility at collection (e.g.: 40%). These stallions are poor candidates for transported semen, but may be satisfactory breeders at the farm.

The stallion owner will also have to have enough shipping containers available to meet the demand during the peak of the breeding season. More and more stallion owners are moving toward the “disposable” or “day” shippers. These are made of cardboard and styrofoam, are low cost, and can be included with the shipping costs quite easily. They are not required to be returned, thus reducing some of the shipping costs for the mare owner. They are also lighter and smaller, and thus cheaper to ship, than the Equitainer. These containers are adequate in most situations. The only time that they may not work is when there are extremes in temperature, such as early in the breeding season when temperatures are below freezing, or when shipping to or from the southern US during late spring or summer when temperatures are approaching or over 30º C.

It is important for the stallion owner to set up a shipping schedule for his horse. It would be nice to accommodate all requests for semen when they occur, and if there are only 1-2 mares being bred, then this will work. However if there are large numbers of mares to breed, it is important to set up a collection schedule and stick to it! The most common are a ‘Monday – Wednesday – Friday’ or an ‘every other day” schedule. The schedule should be available to the mare owner at the beginning of the season so that it will be possible to fit the mare’s breeding into that schedule. Any days that the stallion will be unavailable should also be made known. Statutory holidays, such as Canada Day, or Memorial Day in the US should also be noted. On these days, it may not be possible to ship semen, as the courier services are closed. One oddity is Good Friday, which is a holiday in Canada, but not the USA. It is possible to have semen shipped from the US on Good Friday, and be picked up in Canada on the Saturday.

From the Mare Owners Perspective

Not having to ship the mare great distances, and at great expense, to have her bred is the most obvious and largest benefit for the mare owner. We can breed a mare living in Alberta to a stallion standing in Florida without her having to leave the farm. But we do have other obstacles to overcome as a result of this. Most mare owners are happy not having a stallion around all of the time, but in order to get our mares bred, we do need some means of heat detection. Some mares will tease to a gelding that is at the farm, or have some obvious change in behavior when they are in heat. With others it is not nearly so evident, and availability to a stallion will be necessary. This may be accomplished by gaining access to a neighbor’s stallion daily, or by taking the mare to a stallion station or veterinary clinic to be bred. Daily teasing is essential to the success in getting the mare bred. Daily palpations or ultrasounds are also recommended once the mare is in heat to more accurately pinpoint when the best time to order the semen is. There are a number of stallion stations that have the veterinarian there daily, or a number of veterinary clinics that will provide the necessary services to breed the mare. Less frequently you may find a veterinary clinic that will provide the services to the mare on the farm. Whichever way will work out for the mare obviously will have some costs associated with it over and above the costs associated with collecting and shipping the semen. These must also be factored in when deciding if it is worthwhile transporting semen to the mare. When shipping semen from the USA, remember that GST is payable on the total value of the stud fee in US dollars. This is payable on each shipment, whether it is a re-breed or not.

Keys to Success
Communication is the number one key to success in a transported semen program. There must be good communication with the mare owner and the stallion owner prior to the breeding season to get all contracts and paperwork done, all fees paid, and all information exchanged. There must be good communication between the mare owner and the veterinarian or stallion station manager as to what must be done to get the process to be successful. Once the mare is in heat, there must be good communication between the stallion owner and the veterinarian that is palpating the mare and ordering the semen. Good harmony in this communication triangle is essential to withstand the rigors of adding a transportation system to the middle of the whole thing! Many of the best planned breedings simply did not occur as a result of the semen simply not arriving. This is probably the number one frustration to all involved, and must be an expected occurrence at some time during the breeding season.

When a mare owner is first contacting the stallion owner, it is valid to ask questions regarding the success rate that the stallion has had with shipped semen. The number of cycles per conception and the conception rate are two important statistics that are useful in evaluating the job that the stallion and stallion manager are doing. It is also valid to ask a US owner if they have ever shipped to Canada, and are aware of some of the problems that may be associated with that.

The second key to success, and equally as important as the first, is paying attention to detail. If all aspects of the transported semen process are adhered to properly, and even the smallest details paid attention to, then the success rate should be very acceptable. This is especially true when dealing with the courier or transportation company. Knowing how and where they pick up and deliver, hours of operation, days of operation, etc. will reduce the frustration when dealing with them and increase your success. For example, when shipping via FedEx from the USA on a Friday, it must be marked on the shipping form for a Saturday pickup in Canada at the depot. FedEx does not deliver on
Saturday, and if not marked for pickup, they will not sort the package until Sunday, and will then deliver it to you on Monday – too late to breed the mare!

Transported semen is a tremendous system for providing access to stallions for mares that may never have the chance to breed to those horses otherwise. The system does work well when everything lines up correctly. Unfortunately in life, things do not always go according to plan, but with a little patience, persistence, communication, and determination, the next world champion foal may be the result!