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Epitome on Frozen Semen Technique

Care and Handling of LN2 Containers

1. Containers should not be dragged on the ground, should be lifted by handles and be placed gently on the ground.
2. They should not be welded.
3. Don’t plug it tight while holding liquid gases.
4. Don’t keep the containers dry and warm, frequent cooling and drying reduces the durability.
5. Charge a warm container slowly and steadily.
6. After opening the containers, close it as quickly as possible to prevent evaporation and wastage.
7. Clean them once in a year.
8. To read the level of liquid gases never use a hollow tube. Use wooden stick with suitable markings and dip slowly to the bottom, lift it out and wave it in the air and measure the length of frost to read the level of the LN2 container.
9. Replenish as the level touches the lower one third.
10. Don’t expose your face directly on the vapours. Inhalation of Liquid Nitrogen vapour causes conjunctivities and sometimes fainting.

11. Avoid violent handling; uneven flow and splashing will, cause cold burn (Frost bite). Apply cold water in the event of splashing on the body.
12. Canisters should be inserted into the refrigeration slowly and carefully.
13. Should not handle the refrigerator roughly and avoid tilting and drifting.

Handling of Frozen Semen Straws

1. Remove the neck plug of the container gently.
2. Cool the tip of the forceps sufficiently.
3. Lift the canister properly without disturbing other canisters.
4. Don’t lift the canister containing straws more than the bottom level of the neck of the container.
5. Take one straw at a time with the cooled forceps within 5 sec.
6. Shake the straw, once or twice after holding with your fingers to remove the drops of LN2 entrapped in the sealing to avoid bursting.
7. Replace the canister and neck plug back in position.

How to do thawing

1. Thawing should be done quickly to avoid the death of the sperms.
2. Straw should be immersed completely in the water with the lab seal on the top.
3. Flask should be of sufficient height (15 cms). Every day fresh water should be used.
4. A uniform thawing time and temperature of 30 seconds at 37ºC should be followed.
5. After taking the straw it should be wiped free of water using clean towel or absorbent cotton.

Loading of A.I Gun

1. Hold the straw by lab plug end and give one or two shakes to bring the air space in the lab. plug end to prevent wastage and contamination of semen while cutting that end.
2. Put the factory plug end (double seal) down into the barrel of the gun and load it.
3. With a pair of scissors cut the straw at the lab. seal end over the air space at right angles.

4. If it is cut oblique, semen may leak into the sheath during insemination. Avoid contamination of sheath at every stage.
5. Slip the sheath over the gun and fix the sheath with ‘O’ ring.

Selection of Animal

Before taking the straw from the LN2 container, confirm the animal for proper heat (External os opening, tone of uterus) during rectal examination and don’t handle ovaries.

Method of Inseminations

1.Hold the AI gun with 3 fingers.
2. Evert the vulval lips.
3. Introduce the AI gun at 45ºC and touch the floor of the vagina.
4. Guide the tip of the AI gun to the external os and fix it.
5. Without applying force, slip the cervix on the gun.
6. Correct site of insemination using frozen semen is 50% at the internal os and 50% in the mid cervix in the fresh (first) insemination.
7. If repeated within 30days, the entire quantity is deposited in the mid cervix itself.
8. Safe level for the frozen semen straw in the LN2 container is 15cms.
9. If it reaches 15cms never open the neck plug.
10. Arrange for topping up of LN2.
11. If any sweating is noticed on the external wall it indicate that the container is defective.


Testing quality of the straw should be done only at the Lab.

1. Inseminate the cow as quick as possible after preparing the AI gun.
2. Handle the cow and AI gun gently.
3. Don’t expose the AI gun to sunlight.
4. Warm the AI gun by rubbing by hand during cold weather.
5. Clean the vulval lips and evert it before inserting AI gun.
6. Inseminate at body of uterus and don’t go into the uterine horn.
7. Forward massage cervix gently, tickle clitoris and massage well.
8. Train your attendant properly about correct handling of frozen semen.

1. Conception Rate

Total no. of animals inseminated (prior to 3 months).
First insemination - 100
Total no. of positive cases - 60
Total no. of negative cases - 30
Total no, of sold etc. - 10
100 x 60
Conception Rate = ----------------- = 66%

2. Calving Rate

Total no. of inseminations done (prior to 10 months)
First insemination - 100
Total no, of positive cases - 60
Total no. of bull calves born - 25
Total no. of heifer calves born - 20
Total no. of sold etc. - 15
45 x 100
Calving rate = ---------------- = 60%

Edited and Presented by
Dr.R.V. Vijayakumar, M.V.Sc.,
VAS,VD, Thirumalaipatty,Namakkal
Mobile: 9-443-217-843