Artificial Insemination

Artificial insemination (AI) is the technique used to manually deposit semen, collected from a stallion into the uterus of a mare at the optimal time in her oestrus cycle to achieve pregnancy. Management of the mare and timing of insemination will be determined by which semen is chosen: fresh, chilled or frozen.

What are the benefits to AI?

Reduced risk of disease transmission.
Decreased risk of injury to mare, stallion and personnel involved.
Expanded stallion options: stallions can be located in the UK, overseas or even deceased.
Ability to monitor semen quality.
Increased breeding efficiency per ejaculate, as one ejaculation originate multiple doses.
No need to travel the mare to the stallion.
Reduced physical demand on the stallion.
Allows stallions to continue competing without interruption during the breeding season.

The semen is collected from the stallion and must be immediately implanted into the mare. As a result, this procedure is typically performed with both the mare and stallion in the same location.

Semen that is to be used within 48 hours of collection, needs to be mixed with an extender to prolong its lifespan and then stored at a special container, that is chilled at 4ºC, airtight and light free.

Semen it is intended to be used after 48h of collection, needs to be subjected to a freezing process, and needs to be stored and transported in liquid nitrogen (at the temperature of -196ºC). To be used, needs to be thawed immediately prior to insemination and the mares must be inseminated within 6h of ovulation to maximizing pregnancy rates.

Chilled semen

Ideally, the mare will be inseminated with fresh or chilled semen within 24 hours prior to ovulation (although many stallions will have semen which will survive for longer than this).

Check list:

Does the stallion's semen chill and travels well?
Which days they can collect from the stallion and send the semen?
How much notice you will have to give for them to collect and send the semen?
How many doses of semen are you buying and are transport costs included?
Semen coming from abroad must be accompanied by the appropriate health certification!

Frozen semen

The frozen-thawed semen has a relatively short life span and therefore requires a more intensive management from the mares since mares need to be inseminated immediately before or after ovulation.

The bigger advantage of using frozen semen is that it can be kept for years, the ability of using stallions which are still competing, or which are based abroad or which are deceased, and avoids “non-arrival semen” for prepared mare to receive semen within 24h.

Check list:

Ensure that the semen is shipped prior to the mare being in oestrus.
Buy from a reputable stud / agent.
Ask for details on semen quality, post thaw motility and pregnancy rates.
How many doses of semen are included in the price? Will there be extra transport costs?
Ensure that the semen is correctly transported to be viable.
Frozen semen should be shipped to us to store in our liquid nitrogen container prior to preparing the mare for insemination.
Semen coming from abroad must be accompanied by the appropriate health certification!

Post-insemination follow-up

Following insemination, your mare will be checked for ovulation and for post-breeding problems Treatment may be necessary, especially for older or problematic mares, such as uterine lavage or oxytocin administration. It is crucial to conduct the first pregnancy diagnosis approximately 14 days post-ovulation to detect twins or determine the need for further follow-up. We strongly recommend a pregnancy scan at 28 days to confirm a viable embryo with a heartbeat, and another at 45 days. After this period, pregnancy loss is less common, and by five months if any loss, the aborted foetus is usually visible.

Sussex Equine Hospital is approved by BEVA to provide AI services with fresh, chilled or frozen semen.

Find out more about that here.

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