VGO 511: Veterinary Andrology and Reproductive Techniques (1+1)

DILUTION OF SEMEN

• The French mini/medium straw is packed with 20 million sperms.
• The final dilution is calculated based on the semen volume, concentration and packing volume.
• Till the final dilution rate is decided, 1:1 diluted semen has to be kept in water bath of 34 ⁰ C.
• This time period will also help to adjust and stabilize the semen with the diluents.
• Then it is placed outside the water bath at room temperature (20-22 ⁰ C).
• Here it is placed for 10 minutes to bring the 1:1 diluted semen temperature to 20-22 ⁰ C.
• The final dilution is done at room temperature of 20-22 ⁰ C.

The final dilution of semen in Tris-Egg yolk-Glycerol diluent/Universal diluent is done at 22⁰C. The diluent used for dilution should also be at 22⁰C.

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Example

Calculation of dilution rate

For French mini straw

• The French mini straw is having 20 million sperms in 0.25 ml.
• Let us consider the

• The total diluted volume is 62.5 ml which includes the semen volume also.
• Hence, to the 5 ml semen 57.5 ml diluents is added to make the final volume of 62.5 ml.
• The semen is already diluted with 1:1 dilution rate ie. to 5 ml of semen 5 ml diluent was already added.
• The present available volume is 10 ml. So 52.5 ml of diluent has to be added as per the dilution rate.
• In a sterile beaker (of 100 ml) add 40 ml of diluent. To this add the 1:1 diluted semen ie. 10 ml.
• The remaining 7.5 ml diluents is added to the collection vial and it is poured into the beaker.
• When the diluents or semen is poured into the beaker it has to be passed via the side walls of the beaker.
• It should not be poured directly into the beaker. The air bubble formation should be avoided while dilution is done.

The dilution rate is calculated based on the number of sperms to be packed in the straw. In both French mini and medium straws 20 million sperms are packed.

(Click here for video demonstration)

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