Frequently Asked Questions

At Hilltop Farm, we strive to make the breeding experience as easy as possible for you and your vet. Please contact us at any time with questions you may have.

May I come visit the stallions?

Definitely!  We encourage breeders to come visit the stallions and offspring that may be at Hilltop Farm.  Please note however that not all stallions are located at Hilltop or may reside here only during breeding season.  We do ask that you call to schedule your visit to ensure we have staff available to show you around.

Can you help me with a stallion recommendation?

Hilltop Farm is committed to assisting our breeders in reaching their breeding goals. Our website, DVD, and Stallion Brochure are excellent starting points in your research, but we also enjoy connecting with you individually and learning more about your mare and breeding goals.  Our Help Me Match My Mare form is a great starting place for us to provide you individualized feedback, but you are welcome to call or email at any time.

How do I secure a space in a stallion’s book?

In order to secure a space in a stallion’s book, a breeder must return a contract and payment.  We cannot hold spaces in a stallion’s book without submission of a signed contract. It’s always a good practice to give us a call or send an email if you do not hear from us within a few days of submitting a contract to verify its receipt.

Where do I find a stallion’s breeding contract?

Each stallion’s contract(s) can be found on their respective stallion page.   Under the green “Breeding Information” bar, you’ll find links for information on the Fees, Breeding Forms, Shipping Guidelines, Mare Management, and Registration Information. Stallion contracts for download can be found in this section as well.

Breeders which prefer online submission of their contracts can easily submit a contract on the Book a Contract page.  This option allows you to quickly submit a contract and submit payment through PayPal.

What is a Mare Breeding Passport?

The Mare Breeding Passport is a form, provided by Hilltop and signed by your veterinarian, which supplies Hilltop with written confirmation of your mare’s insemination dates, pregnancy check dates, and pregnancy status. A Breeding Passport must be returned in order for a Breeding Certificate to be issued for the respective foal or for a breeder to receive a rebreed year on their contract. Return of a completed Mare Breeding Passport is a required by your breeding agreement.  Click here to download a copy of the Mare Breeding Passport.

How do I get a Breeding Certificate to register my foal?

Breeding Certificates are emailed each winter to mare owners with mares confirmed in-foal to a Hilltop stallion.  Breeders must return a Mare Breeding Passport to receive their mare’s Breeding Certificate, as the passport supplies all the necessary information for completion of the Breeding Certificate.  Certificates may be held until accounts are settled with either Hilltop Farm or Select Breeders Services.

How do I request a semen shipment?

Instructions on how request a semen shipment can be found here. We’re happy to go over any questions you or your vet has about the collection notification schedule prior to the requesting semen. It is particularly important to be aware of our semen request deadlines and dates of availability for the stallion you’ve selected.

Why are some stallions available with a LFG & others by the dose?

Availability of each stallion is determined by the current inventory of frozen semen of the stallion or by cooled semen access.  Our preference is to sell each stallion with a multi-dose contract, but we work closely with each individual stallion owner to plan the contract approach that best fits their stallion’s availability and meets the needs of our breeders.  When our frozen inventory on a particular stallion is very limited, offering a per dose option allows more breeders access to the stallion.

What does a dose of semen consist of?

Each breeding dose of cooled semen distributed by Hilltop Farm consists of at least 1 billion total sperm and at least 500 million progressively motile sperm per dose.  While processing is individualized for each stallion, in general our doses have a minimum of a 3:1 dilution.  We most commonly use an SMG extender with Timentin and volume per dose is typically 40-60ml.

Each dose of frozen semen distributed by Hilltop Farm meets the industry recommended minimum for frozen semen of at least 200 million progressively motile sperm/dose; though, most of our stallions well exceed this.  On average, SBS freezes 800-100 million total sperm cells per dose, which results for most of the stallions in 300-400 progressively motile sperm.  All semen shipped meets or exceeds 30% progressively motile sperm/dose. All of the stallions frozen by SBS, and almost all the stallions we import semen from, are frozen in .5ml straws.  The number of ‘straws’ per dose will vary based on stallion and specific lot (typically the range is 3-8 straws/dose).

Your frozen semen has undergone SBS Quality Control. What does that mean?

To ensure the highest level of service for our breeders, Hilltop Farm has Select Breeders Services (SBS) perform quality control testing on all of the semen we represent.  SBS is the largest provider of frozen semen services in the world.  With unrivalled expertise accumulated over 25-years in the business they are recognized by breeders and veterinarians as the most trusted source of frozen semen in the industry.

SBS independently verifies post-thaw motility, velocity, and concentration of the frozen semen to ensure the semen meets their recommended minimum for commercial distribution of 30% post-thaw progressive motility.  Based upon the results of post-thaw analysis by SBS, we can also ensure each dose includes the industry recommended minimum number of progressively motile sperm per dose, optimizing your chances of conception.

In addition to determination of sperm concentration and motility, bacterial cultures are performed to test for potential mare pathogens, either originating in the semen or from contamination that may have occurred during the semen collection or freezing process.  Unfortunately it is not uncommon for us to find bacterial contamination in semen.  SBS estimates that approximately 80% of the semen they test from Europe shows bacterial growth (as opposed to approximately 6% of the semen they freeze) and about half of the imported semen produces a heavy growth of bacteria.  If the cultures show bacterial growth, we then submit samples to the University of Pennsylvania’s New Bolton Center for secondary culture and identification, to determine if it is a potential pathogen for the mare’s reproductive tract.  Hilltop Farm and SBS will not distribute semen containing known mare pathogens.  Semen containing bacteria not regarded as mare pathogens can be considered contaminants and will be shipped with a Contamination Notice providing your vet with information on the bacteria founds. If your veterinarian views your mare(s) as susceptible to uterine infection then post-insemination intra-uterine antibiotic therapy may be indicated.

Do you keep fertility data on the stallions?

We do compile fertility data on each of the stallions we manage and that is one reason breeders are required to return the Mare Breeding Passport.  Call us to discuss fertility details on the stallion that interests you.

What if I have an emergency question and your office is closed?

Hilltop Farm’s office hours are Monday-Friday 8:00am-4:00pm.  After hours emergency voicemails should be left on extension 702.  Your voicemail will be forwarded to the appropriate person and responded to as soon as possible.

Warmblood Fragile Foal (WFFS) Syndrome FAQs


Warmblood Fragile Foal Syndrome (WFFS) is an inherited systemic connective tissue disorder that is found in Warmblood horses. Skin lacks tensile strength (extreme skin fragility characterized by tearing, ulceration, etc. from contact with normal surroundings). Lesions can occur anywhere on the body but are most noted on pressure points and in addition to skin wounds, lesions are found on the gums and other oral cavity mucous membranes and the perineum. Limb joints are lax and hyperextensible. Fetlocks are the most dramatically affected and affected foals cannot stand normally. Other symptoms may include hydrops, subcutaneous emphysema, hematomas, or premature birth.  Affected foals must be euthanized soon after birth.

WFFS is caused by a single mutation in lysyl hydroxylase 1 (LH1) gene. Mutations in LH1 are known to cause a similar disorder in humans known as Ehlers-Danlos Syndrome (EDS).  The skin defects resemble, but are much more severe than those seen in the Hereditary Equine Regional Dermal Asthenia (HERDA), which has a later onset of symptoms.


Genes come in pairs with each parent contributing one copy to their offspring. With autosomal dominant genetic diseases only one defective gene is necessary to express the genetic disease in question. Such a gene can be inherited from either of the parents or from both parents. With recessive genetic diseases two copies of an abnormal gene (two copies = a pair) must be present for the horse to show signs of the genetic defect. WFFS is an autosomal recessive trait, meaning a foal can only be affected if the foal inherits the disease from both parents. Horses with only one copy of the defective gene are considered “carriers”.


Initial estimates were that between 6%-11% of the Warmblood population are carriers of WFFS but the test has not been widely utilized and as more people test we will better understand the true carrier rate.  From our own experiences over the last few months, we are seeing a carrier rate around 10%.


If both the sire and dam are clear of the gene mutation (N/N), then there is no chance of an offspring inheriting the mutation.  If a carrier of the recessive allele (N/FFS) is bred to a normal horse (N/N), each foal has a 50% chance of having two copies of the normal allele (N/N) and a 50% chance of being a carrier (N/FFS).  If two carriers are bred, each foal has a 25% chance of having two copies of the normal allele (N/N), a 50% chance of being a carrier (N/FFS), and a 25% chance of being affected (FFS/FFS).

So within the warmblood population, assuming a conservative 8% carrier status, the following statistics could be assumed.  Out of 100 broodmares, approximately 8 would be carriers of the WFFS allele.  If those 100 mares were bred to a carrier stallion, approximately 50 foals would inherit carrier status (N/FFS), 48 foals would NOT inherit the recessive allele and would be clear of the gene mutation (N/N), and 2 foals would be positive for the disease (FFS/FFS).


The focus for breeders needs to be on reducing risk and avoiding carrier-to-carrier breedings (which are the only combination that can potentially result in the fatal disease being inherited).  With the vast majority of stallions and mares being untested, a breeder that tests their own mares will know either that their mare is clear of the mutation and regardless of the stallion’s status a foal would not inherit the actual disease OR that the mare is a carrier and while she herself won’t have any health risks, it will be important to know the status of potential stallion combinations for her and choose only to breed to a stallion who is himself clear of the recessive allele.


Testing is easy. It’s a simple hair pull (they can also test blood or semen) just like you are used to doing for DNA Proof of Parentage.  Initially Animal Genetics was the only lab in the US offering this test.  Many labs now offer this testing including UC Davis, with which many of the sport horse registries have negotiated discounted rates for their members.  You may not even need to pull new hair samples if your horse’s DNA is already on file at UC Davis.  Etalon Diagnositics also offers WFFS testing.


Yes, carrier horses can still be used in our breeding programs.  While there is a 50% chance they will pass along carrier status to their offspring, as long as we avoid carrier-to-carrier breedings we can prevent any potential foal losses due to WFFS.  At Hilltop, we will be requiring any mare breeding to a carrier stallion to have been tested negative/clear of WFFS. 


Unfortunately no.  We cannot assume status backwards as even two carrier individuals can produce a clear offspring.  However, we do know that two clear parents will always mean a clear offspring.


On the pages of the stallions Hilltop Farm represents, you will find their testing status published (along with EVA status, color testing, etc).


WFFS carriers have not been systematically studied. Extrapolating from what is known from human studies, this recessive allele would not be expected to have a marked affect on the health of your horse or its performance potential. If it is a mare or stallion, it would be recommended you test prior to breeding but there is no need to test geldings.