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

FILLING AND SEALING OF SEMEN STRAWS

(Filling of straws (Manual method), Sealing of straws (Manual method) and Filling and sealing by machine)

Filling of straws (Manual method)

Manual method of filling requires vacuum pump, filling comb, rubber tube, straw clips and polyvinyl alcohol powder (PVA).

• The manual method of filling requires vacuum pump, filling comb, rubber tube, straw clips and polyvinyl alcohol powder (PVA).
• The straws (15 medium or 20 mini) are clipped together by using straw clips. The clipped straws are cooled to +5°C in the cold handling cabinet.
• The straws in the clamps are fitted on the filling comb (factory seal near the nozzle), which in turn is fixed to vacuum pump through the rubber tube.
• Semen is taken in the bath of the bubbler and filling is done by operating the vacuum pump and slowly dipping the open end of the straw.
• Due to negative pressure semen is drawn into the straws. Appearance of two distinct bands in the factory seal indicate complete filling of straws.
• A uniform air space is created in all the filled straws by pushing the open ends of the straw on to the teeth of the bubbler.
• The bubbler and the bath are discarded after use. This small amount of air space is required in order to allow for expansion of the semen during freezing.
• In it’s absence the sealing will be pushed out by the frozen semen.
• Further this air space also prevents contact of scissors with semen at the time of cutting of straw before insemination, thus preventing possible contamination.

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Sealing of straws (manual method)

Manual sealing is done with poly vinyl alcohol powder (PVA). It is available in 10 different colours.

• The sealing powder PVA is available in 10 different colours.
• The French straws are available in 16 different colours.
• The combination of both assures 160 positive identifications.
• The sealing powder is spread on a clean glass dish to provide a thickness of 4-5 mm.
• The open ends of filled straws are dipped into the powder and when the powder penetrates 4-5 mm into the straw a satisfactory seal is made.
• This is known as ‘laboratory seal’ which will appear as a single band.
• Immediately after sealing the sealed end of the straws are placed in water bath at 20°C for 10 minutes for firm sealing.
• Then the straws are taken out and wiped of water and sent for printing of the straws.
• At the same time this allows the sealing to become firmer and the excess powder on the ends falls to the bottom of water bath.
• The entire operation of filling and sealing has to be done at + 5°C within the clod handling cabinet.

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Filling and sealing by machine

• Automatic filling and sealing machine is also available for filling and sealing of semen.

Automatic filling and sealing is done with filling and sealing machine. It is faster than manual method.

• Both operations are done within a shorter time and with least handling of semen.
• This will be the ideal way of filling and sealing where large scale freezing is undertaken daily.
• The machine MRS–1, MRS-3, of IMV, France have capacity to fill and seal 3600 and 12960 as the sealing is done by compressing the end of the straw.
• Recently MRS 5 has been launched which is faster than above.

(Click here for video demonstration)

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