Once frozen, your stallion's semen keeps indefinitely in liquid nitrogen. It allows him to be used during his sporting career without interrupting it, and preserves his genetics should castration or an accident end his breeding career.
We carry it out in a centre approved for intra-community trade, from the first collection to the storage of the straws.
Castration planned, or stallion deceased? Epididymal sperm freezing ↓
Before you come
We arrange the health tests with you, then the collections as soon as their results are known.
First, choose where the semen will go
The health status of a batch is fixed at the time of collection, according to the tests carried out on the stallion, and does not change afterwards. Semen frozen for Belgium can never be sent to another EU country, because the required tests were not carried out at the right time.
For Belgium, the stallion is tested for contagious equine metritis (CEM) and equine infectious anaemia (EIA), after 30 days without natural cover.
For the European Union, programme C, reserved for frozen semen, requires no stay at the centre.
For a third country, requirements vary from one country to another and must be established before the first collection. Discovered afterwards, they are almost always impossible to meet.
How many doses can you expect?
We collect the stallion every other day. Less frequent collections do not increase the yield, as part of the stored sperm is lost; more frequent ones deplete each ejaculate.
A dose contains 80 to 160 million progressively motile spermatozoa, meaning sperm that move forward. The number of doses per collection therefore depends on the stallion's output, then on the proportion of progressive sperm at collection and after freezing.
Not all stallions freeze equally well, and fertility with fresh semen says nothing about resistance to cold. Each batch is therefore checked after thawing, and the first collections allow the target to be adjusted on an informed basis. A batch that does not reach our quality threshold is not marketable; we tell you so, and the freezing fee is reduced.
Estimating a stallion's output
Daily sperm output is related to testicular volume, measured by ultrasound (Love et al., 1991).
Volume of one testis (cm³) = 0.5233 × length × width × height
Daily output (billions) = 0.024 × volume of both testes − 0.76
Example, for two testes of 10 × 6 × 5.5 cm, collected every other day:
- Volume: 0.5233 × 10 × 6 × 5.5 = 173 cm³ per testis, 345 cm³ in total.
- Output: 0.024 × 345 − 0.76 = 7.5 billion spermatozoa per day.
- Collection every other day: about two days' output, i.e. 15 billion. This is the typical ejaculate of 50 ml at 300 million per millilitre.
- Centrifugation: a loss of around 20 %, leaving 12 billion spermatozoa.
- After thawing, 40 % progressively motile: 4.8 billion.
- Doses: at 80 to 160 million progressive spermatozoa per dose, 30 to 60 doses per collection.
This is only an order of magnitude; only collection shows what the stallion actually produces.
How the semen is frozen
Immediately after collection, the semen is filtered and centrifuged. This step concentrates the spermatozoa and removes most of the seminal plasma, which weakens them during storage. They are resuspended in a freezing extender whose cryoprotectants limit the formation of ice crystals inside the cells.
The semen is then packaged in straws, cooled along a controlled curve, and plunged into liquid nitrogen at −196 °C.
Health rules for the European Union
Programme C is reserved for frozen semen, and it is the simplest for the stallion, which does not have to stay at the centre. He is tested before the first collection, then a second time after the last. Each batch stays at the centre for at least 30 days, and only leaves once these results are known.
Programme C · frozen semen, no stay at the centre
No stay at the centre is required.
- Day 0, before the first collectionEIA, EVA and CEM 1
- Day 7 at the earliestCEM 2
- Collections C1 to CnThe stallion may go home between collections
- From Cn + 14 days to C1 + 90 daysSecond sampling for EIA, EVA and CEM 1, then CEM 2 at least seven days later
- Each collection + at least 30 daysThe batch may leave the centre, results known
For a single second sampling to cover every batch, the collections of one campaign must fit within about ten weeks. A longer campaign requires an additional sampling.
Programmes A and B, which require a stay at the centre, are described on the Semen collection page.
And after freezing?
The straws are stored in our tanks, free of charge during the year of production, then under the storage contract. They can be shipped to another approved centre, or handed over to the breeder who will use them. The Storage and distribution page gives the details.
A straw handed over to a breeder leaves the commercial circuit for good. According to the Belgian food safety agency (AFSCA), it may then only be used on that breeder's own mares. It may not be resold or transferred, even free of charge, and can never re-enter the circuit, whatever its date and place of production. To keep marketing your stallion's semen, leave it in an approved centre. A national storage centre would also cause it to lose its EU status permanently.
If you wish to store and market your stallion's semen yourself, you can apply to the AFSCA for a storage authorisation for national trade, or for approval as a storage centre for intra-community trade. We can help you with these procedures.
Epididymal sperm freezing
When a stallion has to be castrated, or has just died, the spermatozoa stored in the tail of the epididymis can still be recovered and frozen. Castration can take place at our centre, in a clinic or at your premises, by your own veterinarian.
You remain the link between your veterinarian and us. You organise the process, and we are happy to contact your veterinarian at your request.
From removal to our laboratory
- You notify us before castration, or as soon as the stallion has died, and return the epididymal freezing form to us.
- The veterinarian removes the testes with the epididymis intact, keeping the tail of the epididymis and as much of the vas deferens as possible, ligated.
- At the latest at the time of removal, a blood sample is taken for EIA and three swabs in charcoal medium for CEM.
- The testes are packed dry in a clean, labelled bag, then chilled at 4 to 5 °C, without direct contact with ice.
- They reach us as quickly as possible, ideally within 24 hours, 48 hours at the most.
After death, the semen can only be certified for Belgium, as the EU tests require samples from the stallion after collection. Epididymal straws are often few in number; in ICSI, a single spermatozoon is enough for each oocyte.
Prices
The freezing fee is reduced if the batch is not marketable. To this are added the collection, the health sampling, the stallion's boarding, and then storage beyond the year of production.
| Epididymal sperm recovery | 324,58 € | Dissection of the epididymides and recovery of the spermatozoa. Freezing charged extra. |
| Freezing | 445,20 € | |
| Freezing, non-marketable batch | 159,53 € | Reduced rate, applied when freezing does not yield a marketable batch. |
Stallion services are invoiced by Linalux Equins, veterinary care by Dr Paindaveine.
Frequently asked questions
What if the semen is of poor quality?
We tell you after the first analysis, with figures. Depending on the case, a different preparation of the semen or ICSI may still make good use of it. We discuss it with you before deciding.
How long does frozen semen keep?
With no known time limit, as long as it stays in liquid nitrogen. Straws frozen several decades ago still produce foals.
Can a batch frozen for Belgium later be sent to another EU country?
No. The health status of a batch is fixed at the time of collection, and the EU tests must be carried out on specific dates, which cannot be made up afterwards.
Can I take my straws home?
Yes, to inseminate your own mares. But once they have left an approved centre, the straws leave the commercial circuit for good. They can no longer be sold or transferred, and will never return to it. If you intend to market your stallion's semen, leave it in an approved centre, or have your own storage facility approved; we can help you with that.
Tell us about your stallion
A phone call is all it takes to prepare a freezing campaign, or simply to talk it over.
Have the stallion’s passport to hand. We then contact you to set the dates of the tests and collections together.