Last week I discussed natural cover, this week, its all about artificial insemination (AI)!
AI has advantages and disadvantages, as does everything else in life. It allows you to use the semen of a stallion hundreds of miles away, but by the same leaf, it can also increase fraud. There is no risk of injury to mare or stallion, and less risk of disease, however it is expensive, and a qualified practitioner is required to administer it.
Advantages of AI
- You can use the semen of a stallion from the other side of this hemisphere
- No injury risk to either mare or stallion
- Less risk of disease spread
- One ejaculation can cover several mares
Disadvantages of AI
- Qualified practitioner required to perform procedure
- It’s a lot easier to mistake a tube of semen from one stalliuon for another’s than it is to mistake the actual beasts!
- Fraud may be a problem, as semen from a lesser stallion can be shipped over just as easily
- Cooled sperm has a lowered success rate than fresh, and cooling is the only way to prevent immediate death.
Harvesting the semen
A phantom mare with an artificial vagina, and a compartment for collecting semen is used to harvest semen. The stallion is teased with a mare, who may be put into a pen behind the phantom mare. The stallion is allowed to see the mare, and sniff her through the pen, then he is encouraged to mount the phantom mare. After about 30 seconds he ejaculates into the artificial vagina, and thus the collection vial.
Preparation of the Semen
A sample of the semen is placed into a sperm counter. This counts how many sperm are present per millilitre, and allows the operator to calculate how much the semen can be diluted. The semen is diluted with semen extender, which acts as a nutrient source for the sperm and a small amount of antibiotic which prevents disease, and removes the sperm’s waste products.
Once fully assessed, the semen is loaded into syringes and put in a polystyrene container with chiller blocks, which cool the semen to about 5 degrees celcius. They are now in a cooled state. They can remain like this for 24-36h.
They can also be frozen in liquid nitrogen to -196 degrees celcius, and they can remain like this for years. It is frozen in very small straws, such as a 1/2ml straw. Each straw is labelled, and stored in a large container, where they are immersed in liquid nitrogen to -192 degrees celcius . As little as one straw can be used per insemination, however some stallions need about ten or twelve.
The huge advantage of this is that semen can be stored for years after the stallion is deceased, and still be perfectly viable, however, some sperm do not respond well to this treatment.
Inseminating the semen
The mare is tied in AI Stocks, and her tail is wrapped and tied to keep it out of the way. The mare’s vulva is washed and dried, and a shoulder-length glove is worn by the practitioner. Non-spermicidal lubricant is applied to the glove, and a syringe is attached to the capheter (straw) containing the sperm. The capheter and the hand are eased into the vagina, and the index finger is used to identify the cervix. The capheter is guided into the uterus, and the semen is released into the uterine body. The capheter and hand are withdrawn, and the AI procedure is complete.
More can be found on pregnancy in my article on the subject. Next week, its all about embryo transfer!