Semen Collection & Freezing

Semen Collection and Analysis

Artificial Insemination (AI) is a popular and routine procedure for breeding sports horses.

Semen is collected from the stallion using an artificial vagina following the mounting of a dummy mare by the stallion. This can be performed either at a local AI centre, or at your own premises if suitable. Penile swabs for venereal disease and blood sampling for infectious disease must be taken prior to semen collection or entry onto the stud. Initial semen analysis involves assessment of ejaculate volume, sperm motility, velocity and concentration, total sperm count and sperm morphology.

Test Freeze

The semen of new stallions will undergo a test freeze so that we can identify a suitable freezing extender for each stallion.  The semen is then subject to centrifugation. This concentrates the semen into a sperm pellet, which is then re-extended into various semen extenders containing the cryopreservant.

The semen is then placed into 0.5ml straws and chilled prior to freezing. Following cryopreservation (freezing), the straws are then thawed and semen is assessed under the microscope for progressive motility and morphology.

Semen must be at least 35% progressively motile following thawing of frozen semen to be commercially viable. Each ejaculate will provide approximately 5-10 insemination doses and each dose usually contains 6 straws. The total number of doses frozen will depend on owner requirements.

Storage

Following successful cryopreservation, the frozen semen can be stored at Rossdales Laboratories. An information sheet will be provided to you and the stud regarding the semen, dosage and thawing instructions.

Problem Stallions

It is known that a percentage of stallion’s semen will fail to freeze well and some may not freeze at all. In such cases these stallions require advanced testing consisting of trials with other extenders, and with alteration of the freezing and thawing processes.

Some stallions that have problems mounting the dummy may have semen collected using a chemical ejaculation technique.

Epididymal sperm recovery

In the event of death of a stallion or sudden requirement for castration, epididymal sperm recovery can be performed and the recovered sperm can be frozen for use at a later date.

Testicles must arrive at Rossdales within 24 hours of death/castration and must be shipped cooled, but not on ice. In an ideal situation, the testicles will arrive as quickly as possible.

Although this is a fairly simple procedure, it must be noted that often semen recovered in this way is immature and devoid of seminal plasma. This, alongside the inability to test freeze the semen, may result in poorer post thaw fertility. Often 10-30 doses of semen can be frozen in this way.