Effect of osmolality of skim-milk diluents and thawing rate on cryosurvival of ram spermatozoa

Improved conception rates in sows inseminated with cryopreserved boar spermatozoa prepared with a more optimal combination of osmolality and glycerol in the freezing extender

“…(1998) showed that the exposure of bull spermatozoa to hyperosmotic solution as a preparation for cryopreservation caused sperm shrinkage and dehydration, and hence, prevented intracellular ice crystal nucleation during the freezing process. The positive effects of hyperosmotic freezing extender on motility and membrane integrity as well as survival have also been reported in ram (Fiser et al . 1981; Watson & Duncan 1988) and boar (Zeng et al .…”

“…Liu et al (1998) showed that the exposure of bull spermatozoa to hyperosmotic solution as a preparation for cryopreservation caused sperm shrinkage and dehydration, and hence, prevented intracellular ice crystal nucleation during the freezing process. The positive effects of hyperosmotic freezing extender on motility and membrane integrity as well as survival have also been reported in ram (Fiser et al 1981;Watson & Duncan 1988) and boar (Zeng et al 2001) spermatozoa undergoing freezing and thawing. Additionally, it has been reported that membrane water permeability is decreased in human sperm in the presence of glycerol (Gilmore et al 1995), and the permeability prior to freezing is correlated with the motility of frozen-thawed goat sperm (Aboagla & Terada 2003), suggesting that the dehydration of spermatozoa by hyperosmotic extender before addition of glycerol is an important step in maintaining the fertilization competence of frozen-thawed boar spermatozoa.…”

Effects of Thawing Procedure on Postthawed In Vitro Viability and In Vivo Fertility of Red Deer Epididymal Spermatozoa Cryopreserved at −196°C

“…Alternatively, the differences between previous results and ours could also be due to differences in the composition of the extenders used. Fiser et al (1981) found an interaction between the osmolality of the diluent and the thawing rate used so that the freezing of ram semen in hypertonic medium combined with rapid thawing rates provided the highest percentages of sperm survival. The extender we employed was a simple medium with no additional cryoprotectant sugars, but that employed by Söderquist et al (1997) contained lactose, a light hyperosmotic extender.…”

“…The resistance of spermatozoa to the thawing process is dependent on the basic extender used and the concentration of cryoprotectant as they interact with the freezing and thawing rates (Curry and Watson, 1994; Curry 2000). This sensitivity of the spermatozoa to thawing temperatures appears to differ between species (Fiser et al, 1981; Arav et al, 1994; Söderquist et al, 1997; Younis et al, 1998; Eriksson et al, 2000; Sukhato et al, 2001; Soler et al, 2003b) and between reproductive tract sources as has been shown in African buffalo sperm samples (Lambrechts et al, 1999). The effect of reproductive tract source (ejaculated vs epididymal) on sperm resistance to the thawing process might be related to different environment conditions between epididymal and ejaculated spermatozoa.…”

Research and technology for increasing the efficiency and output of lamb production systems

“…More recently it has been established that semen for freezing should be collected during a decreasing daylength when freezability is high and the occurrence of abnormal spermatozoa is low (119). Comprehensive and detailed studies on the factors influencing spermatozoa survival during freezing, the composition of semen diluents, freezing and thawing rates, and their interactions (75,94,133,134,169,170) have resulted in procedures which significantly improve the survival and fertilizing capacity of frozen/thawed ram semen (Appendix B).…”