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Breeding your Mare

Updated 2023


Please find below some information which will hopefully make it easier to decide how to go about breeding your mare.

Vet costs indicated are to be used as a guide only. All mares are different and have different requirements.
Our stallion Service Fee is $1750 (incl GST) and this is for fresh, chilled, transported semen. This includes the first collection of semen for shipment (all of which is outlined in the Breeding Contract).

Extra collections are invoiced at $375 (incl GST) and this is to cover the collecting of the stallion and the materials used, packaging and processing of semen and delivery of the semen container to the Courier depot or airport.
The semen will be sent to you either by same day air freight or via an overnight courier service (you have a choice).

The semen is collected on Mondays, Wednesdays and Fridays.


We need to know the day before you require it, so that your mare can be placed on the list of those who require semen from any given collection.  The semen is collected and carefully prepared in a medium (extender with an antibiotic) which feeds and protects the semen giving it better longevity.

The costs to courier are minimal. Styrofoam shippers on average cost about $30 to ship within the South Island and around $50 to North Island. We generally ship from depot to depot and get our mare owners (or vet) to collect from their depot (usually available first thing in the morning) so that the precious goods are not tripping around in the back of a Courier van for extended periods of time.

The costs to air freight semen vary from airport to airport but generally the cost is around $130 - $150.

The best place and most favourable conditions for semen are inside the mare so we always suggest immediate insemmination as soon as your semen arrives.


There are probably two major keys to successful transported semen breeding -


Carefully preparing your mare, and the associated monitoring of her estrous cycle will hopefully result in a timely breeding.

It is essential that the mare's estrous cycle be followed carefully, and ongoing follicular activity monitored (this is known as "following the follicle").

In order to do this, a person experienced in palpation or ultrasound use is needed. Most vets have had some form of experience at doing this but you will need to check that your vet is comfortable with doing Equine reproduction. A specialist horse breeding establishment may seem pricey but in my experience these people are more likely to attain a pregnancy from the first cycle and therefore end up the cheaper option and many will offer a 'breeding package'.

A mare normally cycles every 21 days. Some factors can alter this at times (to early/late in the year, weather conditions, age of mare etc).

Between 4-7 days towards the end of the mares cycle, she will show signs of being in season (the estrous phase) on the outside, during this time the follicles mature inside the mare, and on or around Day 21 the mature follicle will ovulate. Using a scanner, the operator is able to measure the size and maturity of the follicle to therefore estimate a time of ovulation.

Follicles typically grow between 3-5mm per day, and are unlikely to ovulate prior to being 35mm in diameter.
The semen from the stallion needs to be inside the mare at the time of ovulation and in most cases the vet will ask you to request semen once the follicle has attained 35mm or greater. Your vet may talk to you about using a drug that will ensure that she ovulates in the time that she has the fresh semen inside her. These drugs are very safe to use and are routinely used in equine breeding with no lasting or negative side effects
On average, 2 scans will be required before inseminating. The approximate cost of scans is about $75 (this may vary, depending on distance traveled, individual vet practice pricing, drugs (possible sedation) and consumables used etc).

In our experience here at Trevalda, we DO NOT have to sedate any mares for scans. 

Your vet may suggest a scan a couple of days post insemination to determine that the mare has ovulated the dominant follicle. This can be quite an important scan if the vet identifies at the time of insemination that your mare has more than one dominant follicle that could cause multiple ovulations and therefore higher risk of a twin pregnancy.

Another scan is then needed at about 15-17 days post insemination to determine a pregnancy and rule out the chance of twins (which can be dealt with at this early stage). Please note that a twins in mares is not desirable as it is well proven that the mare will not maintain the pregnancy.

Some then choose to have a scan of their mare at 28 plus days as a heartbeat may then be seen in the scan in your developing baby. Another scan between 45 to 60 days can put your mind at ease and know that the fetus is developing as it should and should be the last scan that is required until the foal is born. 

Once your mare enters her estrous stage, it is helpful that you make contact with us so that we can be prepared to send the semen when required. Here at Trevalda, there is no Courier service available to us over the weekend, so that rules out receiving semen on a Sunday or Monday, but this can easily be worked around with good communication.

Here at Trevalda, I am more than happy to assist in the breeding process and I can collect fresh semen here at the Stud and inseminate your mare immediately. We have an excellent and safe breeding crush and have vets on hand to ultrasound at any time.

Please don't hesitate to contact us if you have any questions regarding breeding your mare

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