Table 4.
Viability of frozen-thawed sperm from dairy bulls, as determined by flow cytometry.
| Bull # | Number of frozen-thawed semen samples | Frozen-thaw sperm viability (%) | Phenotype | |
|---|---|---|---|---|
| Average | Difference from population average (freezability score) | |||
| 1 | 79 | 48.9 | − 5.8 | LF |
| 2 | 107 | 49.2 | − 5.5 | LF |
| 3 | 194 | 52.7 | − 2.0 | LF |
| 4 | 264 | 54.8 | − 0.1 | LF |
| 5 | 71 | 54.9 | 0.2 | LF |
| 6 | 229 | 55.0 | 0.3 | LF |
| Avg ± SE | 157 ± 30.7 | 52.6 ± 1.1 | − 2.2 ± 1.1 | |
| 7 | 138 | 59.3 | 4.6 | HF |
| 8 | 81 | 59.9 | 5.2 | HF |
| 9 | 113 | 61.9 | 7.3 | HF |
| 10 | 153 | 62.3 | 7.7 | HF |
| 11 | 207 | 62.8 | 8.1 | HF |
| 12 | 266 | 63.0 | 8.3 | HF |
| 13 | 50 | 64.4 | 9.7 | HF |
| 14 | 116 | 66.2 | 11.5 | HF |
| Avg ± SE | 141 ± 22.9 | 64.5 ± 0.5 | 7.8 ± 0.7* | |
Bulls had low (LF) or high (HF) sperm freezability phenotypes based on the percentage deviation of the average post-thaw viability of sperm measured in the population of all bulls. Population average of frozen-thaw sperm viability was 54.7%.
*p < 0.001.