Veterinary Andrology and Reproductive Techniques

SHORT-TERM LIQUID STORAGE OF SEMEN

Fertile spermatozoa can be preserved for a short period of time without freezing.

• The gametes of many species can be stored in liquid media which is maintained either at ambient temperature or in a refrigerator at 4-5˚c.
• There are definite advantages to store gametes at ambient temperature, especially where refrigeration facilities may not be readily available.
• The daily fluctuations encountered in storage temperature can present serious problems in maintaining fertile spermatozoa.
• Ambient temperature storage requires prevention of microbial contamination and effective prevention of microbial proliferation without impairment of gametes viability.
• For successful short term liquid storage of semen it is necessary neither to extend the time that spermatozoa are able to maintain high metabolic rates or to slow the process down.
• The first effective ambient temperature storage medium was based on the fact that carbon dioxide markedly reduced the rate of sperm metabolism.
• This storage, medium which was termed Ilini Variable Temperature IVT) extender, was saturated with carbon dioxide by bubbling the pure gar through an egg yolk –citrate extender.
• Other ambient temperature extenders, such as CUE (Cornell University Extenders), utilize similar metabolic inhibition principles.
• Another ambient temperature storage medium called Caprogen extender was extensively field tested in New Zealand and adopted for routine use at a storage temperature of 18-24 C.
• The Caprogen extenders is a modified citrate buffered egg yolk medium containing Caproic acid, Glucose, Glycine, sulfacetamide, penicillin, and streptomycin and is saturated with nitrogen gas.
• The fertility of bovine spermatozoa can be maintained for about 3 days using the common ambient-temperature storage media.

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