Results from this method are also the least reliable, as semen is deposited at the opening of the cervix in the vagina, where the sperm cells have the smallest chance of fertilizing eggs. When cows are artificially bred, an insemination pipette is inserted through the vagina and threaded through the rings of the cervix. The operator inserts his hand into the cow's rectum and uses his thumb and fingers to help guide the pipette through the cervical canal. Semen is deposited into the body of the uterus. In small ruminants, especially sheep, this procedure is much more difficult, due to the smaller body size and more complicated anatomy.
Sheep have a longer and more complex cervix than other ruminant livestock.
It is approximately 12 centimeters in length and has 6 or 7 offset rings which make passage of AI equipment very difficult, if not dangerous to the ewe. There is also a flap of tissue at the opening of the cervix which makes entry through the first cervical ring especially difficult. It is a minimally-invasive, minor surgical procedure. Ewes are held off food and water and given a mild sedative before the procedure. They are placed in a breeding cradle, which is elevated to an angle of approximately 30 degrees.