Preservation of Male Germplasm

Semen preservation is an important tool for the dissemination of genetics. This chapter describes health requirements as well as methods of semen collection and preservation in sheep and goats. The required disease testing presented is based on the Terrestrial Animal Health Code of the World Organization of Animal Health. The advantages and disadvantages of semen collection methods are discussed. Cauda epididymis sperm harvest can be used to salvage genetics from deceased males. The principles of sperm cryobiology and mechanisms of cryoinjury are discussed in detail. The composition and properties of extenders for short-term (refrigeration) or long-term (freezing) preservation are described. There is a deleterious effect of egg yolk and milk on goat sperm due to the presence of lipase from the bulbourethral glands. The addition of antioxidants to extenders to improve the quality of preserved sperm is discussed. The chapter concludes with advanced techniques for semen quality assessment, such as computer-assisted semen analysis, acrosome integrity staining techniques, the hypoosmotic swelling test, and the use of fluorescent stains to evaluate membrane integrity, DNA integrity, and mitochondrial function. Spermatogonia stem cell preservation and transfer are briefly described.