02047naa a2200325 a 450000100080000000500110000800800410001902400280006010000170008824500870010526000090019252011970020165000130139865000100141165000100142165000170143165000190144865000160146765000160148365000120149965000170151165000110152865300150153965300130155465300260156765300230159370000160161670000170163277300720164915233812023-05-24       1990    bl uuuu     u00u1 u    #d7 a10.1071/rd9900027.2DOI1 aRITAR, A. J.  aExamination of methods for the deep freezing of goat semen.h[electronic resource]  c1990  aAbstract: In four experiments, freezing of goat semen in straws was examined and compared with conventional pellet-freezing. The optimum freezing regime was attained by holding straws in vapour 4 cm above liquid nitrogen for 30 s or longer, followed by plunging into liquid nitrogen. Straws exposed to vapour for only 10 s did not cool sufficiently before plunging, and cell viability was seriously impaired. Initiation of ice crystallization and the pattern of cooling of semen depended on size of straws and the type of rack used to hold straws in vapour during freezing. Nevertheless, semen was equally well stored in straws of 0.25 mL and 0.50 mL capacity and straws were most efficiently filled at 30 degrees C. Modified Tris media were used to dilute semen at rates (semen: diluent) of 1:2, 1:5, 1:11 and 1:23. Spermatozoa survived best in hypertonic diluents and deteriorated during post-thawing incubation in media of low tonicity, whilst the optimum diluent depended on rate of extension before freezing. The cooling curves differed markedly for semen frozen in straws in liquid nitrogen vapour and pellets on dry ice. Viability of spermatozoa was better for the pellet-frozen semen.  aFreezing  aGoats  aMales  aReproduction  aSperm motility  aSpermatozoa  aTemperature  aCaprino  aReprodução  aSêmen  aCongelacao  aDiluicao  aOsmolar concentration  aSemen preservation1 aBALL, P. D.1 aO'MAY, P. J.  tReproduction Fertility and Developmentgv. 2, n. 1, p. 27-34, 1990.