VCP 411: Gynaecology and Obstetrics Section

PROCEDURE FOR LOADING AI GUN

• Identify the canister from which the desired semen is to be taken. Ascertain the colour of straw by reading identification tag.
• Remove the lid from the container and lift the proper canister up to the level of the frost line. Never lift the canister above the neck level.
• With a pair of tweezers, grasp an individual straw and remove it, at the same time lower the canister immediately back into the container. If you are unable to take the straw within 10 seconds, lower the canister back to nitrogen wait for sometime and make next attempt.
• With the wrist movement give one or two jerks to the straw to expel liquid nitrogen trapped at end of factory seal.
• Dip the straw into a clean water bath at 37-40 ° C for 30 seconds. During this period the entire straw must be completely submerged in water bath.
• Remove the straw from bath and dry the straw with a clean tissue paper or cotton. Inspect the straw carefully and discard straw with cracks or defective seals. Semen must never come in contact with water.
• Place the straw in the chamber of insemination gun. To obtain a perfect fit with medium straw, it is essential that the laboratory seal be removed by cutting at right angle through middle of the air space. The air space could be brought to the top by gentle tapping of straw. Make sure that the clipped end of straw has a straight clean cut with no jagged edges. Straws cut at other angles or cut too short will result in back flow and wastage of semen at the time of insemination.
• Fit a sheath over the straw and the chamber of the insemination gun. Obtain a perfect fit between the extremity of the straw and the cone of the sheath. Move the sheath about one inch up and check whether the straw follows the sheath. If it is not correctly fixed, it will not move upwards with the sheath. Fix the sheath by locking the plastic ‘O’ ring at the flange of the gun with a rotating motion. Do not touch the sheath in the tip or middle portion. Handle only the base portion of the sheath.  
•  For maximum reproductive efficiency, thawed semen should be used immediately. 
• Sheath are sterilized and packed in 50 or 40 numbers in a plastic packet (smaller packing will be ideal). The base of the sheath packet should be cut open by means of a small cut made at an angle. The sheath packet should be kept inside a sheath container made of aluminum and closed with rubber stopper on either side. After removing each sheath, the container should be tightly closed to keep it free from dust and contamination.

Insemination

• Inseminating between mid-estrus and end of estrus gives maximum results.

Site of deposition of semen

• When liquid semen is used if the site of deposition is whether cervix or uterus, the conception rate is same. For frozen semen, deposition of semen is done at body of uterus.
• Frozen semen must be deposited in the beginning of the body of the uterus.
• Remember that the body of the uterus is only approximately 1 cm in length.