Studies on the presence and absence of glycerol in unfrozen and frozen ram semen Fertility trials and the effect of dilution methods on freezing ram semen in the absence of glycerol

Trials were conducted to study fertility of ram semen under various breeding conditions. In trial 1, 60 cycling ewes were randomly divided into five treatment groups of 12 ewes. Group 1 was bred naturally. Groups 2 through 5 were artificially inseminated with pooled, diluted semen group 2 with fresh, diluted semen; group 3 with semen stored at 5 °C for 6 h; group 4 with semen containing 3% glycerol ( v v) stored at 5 °C for 6 h; and group 5 with frozen-thawed glycerolated (3%) semen. Lambing rates were 83, 91, 83, 41, and 33%, respectively. Trial 2 studied the site of semen deposition and the effect of dialysis on frozen-thawed glycerolated ram semen fertility. Seventy-eight ewes were divided into three treatment groups. Two groups of 33 ewes each were inseminated in the cervix; group 1 with nondialyzed glycerolated thawed semen and group 2 with glycerolated thawed semen dialyzed (110) against TEST-yolk-glucose extender for 30 min at 5 °C. In group 3, 12 ewes received intrauterine inseminations of glycerolated frozen-thawed semen. Percentage lambing rates were 33, 48, and 67%, respectively. Dialysis of frozen-thawed semen did not improve lambing rate significantly (P > 0.05). However, intrauterine insemination of glycerolated frozen-thawed semen yielded a significantly higher lambing rate (P < 0.05). The effect of different dilution methods on survival of ram sperm frozen in the absence of glycerol is described. Ram semen diluted by the cold dilution method and frozen in the absence of glycerol was inseminated into 46 cycling ewes. A lambing rate of 52% was obtained. © 1991

Studies on the absence of glycerol in unfrozen and frozen ram semen. Development of an extender for freezing Effects of osmotic pressure, egg yolk levels, type of sugars, and the method of dilution

Four experiments were conducted to study the effects of (1) osmolality (275 to 500 mOsm at 25-mOsm increments); (2) egg yolk levels (0 to 40% at 5% increases); (3) 10 sugars, 10% ( v v); and (4) two different dilution methods (soon after collection at 37 °C or after cooling to 5 °C) on percentage of motility of spermatozoa before freezing and on frozen-thawed ram spermatozoa diluted in TEST [Tes (N-tris(hydroxymethyl)methyl-2-aminoethanesulfonic acid) titrated with tris(hydroxymethyl)aminoethane to a pH of 7.0]. Glycerol was not used in any of the experiments. Before freezing, ram semen cooled to 5 °C, held for 3 h after collection, and then diluted with TEST buffer at 300-375 mOsm and 25-40% egg yolk ( v v) had the best progressive motility. Overall, the presence of 10% of any sugar ( v v) did not significantly affect the motility of spermatozoa before freezing. Maximum post-thaw motility was obtained when ram semen was diluted cold at 5 °C 3 h after collection in TEST buffer, pH 7.0, 375-400 mOsm, with 25-30% egg yolk ( v v) and 10% maltose monohydrate ( v v). © 1991