======================================================================== Post-thawing motility Dilution Pre- --------------------------------------------------- of freezing After After storage[G] After refreezing[H] semen motility first ------------------- -------------------- (semen: (percent) freezing No Diluted No Diluted extender) further to 15 further to 15 dilution million/ml dilution million/ml ------------------------------------------------------------------------ First trial: 4 samples 1:1 60 49 46 34 31 6 1:10 53 45 36 30 25 5 Second trial: 7 samples 1:9 67 47 41 35 28 11 15 million/ml 67 30 32 .. 18 .. ------------------------------------------------------------------------ [G] Stored at 5 deg. C. for 3 to 7 hours after first thawing. [H] Refrozen following first thawing. Table 8.--Effect of Glycerol Level and Storage at 5 deg. C. on Motility of Sperm in Yolk-Citrate Extender ==================================================================== Sperm motility -------------------------------------------------------- Post- After storage at 5 deg. C. Glycerol thawing ---------------------------- Average level 1 day 3 days 7 days (percent) --------- --------- --------- --------- --------- per- rate per- rate per- rate per- rate per- rate cent cent cent cent cent -------------------------------------------------------------------- Control[I] 56 2.5 55 1.9 46 1.8 38 1.4 48 1.90 0 54 2.4 44 1.9 46 1.8 36 1.4 45 1.87 5 52 2.2 50 1.9 46 1.7 32 1.4 45 1.80 10 52 2.3 46 1.8 42 1.7 28 1.6 42 1.85 20 52 2.1 50 1.7 44 1.6 38 1.1 46 1.62 30 50 0.7 44 0.5 42 0.4 30 0.4 42 0.51 Average 53 2.03 47 1.62 44 1.50 34 1.22 .. .... -------------------------------------------------------------------- [I] The control differed from the 0-glycerol treatment in that no additional citrate or glycerol solution was added. A similar trial was carried out with seven samples; one portion was diluted 1:9; the other was extended at the outset to 15 million sperm per milliliter. Results for both tests are summarized in Table 7.