(Average of 10 ejaculates)
| Glycerol level (percent) | Post-thawing motility (percent)[F] | |||
| Number of sperm (millions/ml.) | Average | |||
| 90 | 30 | 10 | ||
| 5 | 36.0 | 34.0 | 36.0 | 35.0 |
| 10 | 22.0 | 24.0 | 23.0 | 23.0 |
| 15 | 3.2 | 0.9 | 0.2 | 1.4 |
| Average | 20.3 | 19.8 | 19.9 | 20.0 |
[F] Mean initial motility of sperm before freezing was 55 percent.
Four semen samples were split and extended at rates of 1:1 (semen to extender) and 1:10. These were frozen, then thawed and halved. One half was further extended to a level of 15 million sperm per milliliter; the sperm numbers in the other remained unchanged. Each of these halves was split again, and one portion of each was stored at 5° C. for 3 to 7 hours. The other two portions were refrozen.
Table 7.—Effect of Further Dilution and Refreezing on Sperm Motility
After the Initial Freezing of Bull Semen
| Dilution of semen (semen: extender) | Pre- freezing motility (percent) | Post-thawing motility | |||||
| After first freezing | After storage[G] | After refreezing[H] | |||||
| No further dilution | Diluted to 15 million/ml | No further dilution | Diluted to 15 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° C. for 3 to 7 hours after first thawing.
[H] Refrozen following first thawing.