California Riding Magazine • December, 2013

Mare Management FAQs
with Dr. William Swyers

When is the breeding season?
Traditionally in the Northern Hemisphere, the equine breeding season runs from Feb. 1 to June 30. There are breed differences and each stallion owner may set their own dates. Stallions we manage will be available for breeding during the traditional breeding season. In individual cases, stallions may be available for breeding from July through December.

What options are available for mare management?
The mares we manage for breeding can be handled in various ways:
Mares are brought to our facility prior to a breeding cycle. They will be cared for while being managed through a breeding cycle. They can stay until checked in foal or, if from local farms or homes, they can leave and then return for pregnancy diagnosis.
Mares can also be hauled in for each examination during a breeding cycle. It is important that this type of program be set up and discussed in advance because logistics with this kind of management can sometimes be difficult.
There will be a few outside farms where I will travel to provide mare management services. These will be determined on an individual basis and must be pre-arranged. Mares managed at one of our facilities will take preference when management overlaps occur.

What are the breeding days?
From Feb. 1 through July 31 the breeding season is a seven-day a week program. We will be able to manage mares for breeding on any day needed. That said, there are many ways to manage mares so that cycles, breeding dates, and embryo flushes fall on days during the middle of the week. Early management of mares allows these opportunities to occur. Mare owners, breeding managers, veterinarians, including me, would prefer to work during the routine work week because management costs, semen shipping costs, and all costs related to achieving a pregnancy increase when done on the weekend. The expected increase in costs can be anywhere from $200 to $500 a cycle when mares are bred over Saturday and Sunday.
Weekend shipments are often fraught with difficulties: unavailable deliveries by UPS and Federal Express, limited flight schedules, limited staffs, and on and on. Carefully managing mares easily avoids these problems. Short-cycling mares or having mares come off hormonal therapy mid week will in most cases result in mid-week inseminations.

Should I breed my mare with fresh semen, cooled semen, frozen semen or should I have her bred by natural service?
Many factors go into how a mare should be bred. Registry requirements, availability of the stallion, semen quality, inherent fertility of the mare and the stallion are just a few things considered when deciding how to breed a mare. Mare owners should make contact early on with stallion owners or breeding managers when determining routes of insemination. I am also available for consultations when planning a breeding for a single mare or planning a breeding program for all your mares or stallions.

What are the factors affecting semen shipping?
Equine semen is routinely shipped around the country and, for that matter around the world. Fresh cooled semen or frozen semen are the two forms of semen packaging used today. Fresh cooled semen has a limited shelf life of 24 to 48 hours. Mare management is critical in timing when a mare should be bred with in the 24 to 48 hour time span when fresh cooled semen is available. Frozen semen has an unlimited shelf life as long as it is maintained in liquid nitrogen or a liquid nitrogen vapor. Special containers for maintenance and shipping are required. Frozen semen allows mare managers to more easily plan a breeding, but the cost of the frozen semen, its shipment and in many cases the semen fertility are deterrents in its use. We routinely breed many mares a year using all of these techniques. If you have any questions regarding shipped semen please call him anytime.

Should I vaccinate my mare for EVA (Equine Viral Arteritis)?
The recent increase of EVA cases across the country has raised this question. There is a safe protective modified live viral vaccine. Owners and breeding managers of mares bred by our program should consult with their primary care veterinarian and me before proceeding. Mares should be vaccinated a minimum of three weeks prior to being bred and then a booster should be given annually. Mares must be quarantined after vaccination as there is a slight risk of transmission of the vaccine virus.