Artificial insemination (AI) is a technique used to transfer appropriately processed semen collected from a stallion into the uterus of the mare at the correct time in her oestrus cycle in order to obtain a single pregnancy.
The semen used for the AI can be fresh, chilled or frozen. This will depend on the time of storage. Fresh semen can be stored for up to 8h in an airtight, light free container at room temperature. If the semen will be used in more than 8h but within 48h of collection should be chilled to 4ºC and stored in a special container. Semen that needs to be kept for more than 48h is frozen at a temperature of -196ºC in liquid nitrogen.
Advantages of AI
- Stallions from all over the world can be used without needing to send the mare to the stallion.
- Prevents injuries to stallions and also allows safe mating of mares or stallions with existent injuries.
- Al involves close monitoring of the mare’s cycle improving the chances of obtaining a pregnancy.
- One single ejaculate of the stallion can be divided into multiple doses.
- AI reduces the risk of transfer of venereal infection.
- Significant savings are often made on transporting the mare long distances to the stallion and then having to leave it at the stud with the resultant livery fees
The mare is prepared with a deep cleaning of vulva and tail bandaged. By using an aseptic technique with a long pipette the semen is introduced intro the uterus. Depending if the semen is fresh, chilled or frozen will need different warming techniques to reach the correct temperature for the insemination.
We use a computerised controlled semen freezer, which allows us to precisely control the rate at which semen is frozen to maximise its post-thaw fertility. It also allows us to tailor each freezing cycle to the individual stallion maximising the chances of a resulting pregnancy. Freezing of a stallions semen confers many advantages to the stallion and mare owner. These include :
- Insurance – Frozen semen can be stored for a long time and in many cases years after the death of a stallion. If a stallion dies or gets injured and is therefore unable to mate naturally – using frozen semen allows the stallion to continue to produce foals.
- Convenience – transport and storage of a stallions semen is generally much easier to arrange than transporting a mare to the stallion for mating. As the semen is frozen it can be thawed and inseminated when required rather than mating or using chilled semen in advance of a predicted ovulation.
- Cost – Although more frequent veterinary examinations of the mare are required for insemination with frozen semen the overall cost can often be cheaper than other forms of artificial insemination when transport costs, vet visits etc are taken into account.
Semen from different Stallions varies in its ability to withstand the freezing procedure and its pregnancy rates following thawing and insemination but in general:
- sperm of 30% of stallions will freeze well
- further 40% of samples will be be classified as satisfactory
- sperm from the remaining 30% of stallions will not survive the freezing process with a level of motility sufficient to be used for AI.
If there is a risk or previous cases of endometritis then an intrauterine lavage and antibiotics may be required, adding oxytocin injections to make the uterus contract and empty the fluid. Confirmation of ovulation is important so further inseminations are not required.
Pregnancy diagnosis (need to ask gary the days)
Transrectal Ultrasound is recommended x days after ovulation to confirm pregnancy. Further scans on days X and X are. recommended to check for healthy pregnancy.