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Table 3 Clinical data on pregnancy rate of cows inseminated with semen straw containing sperm cells selected prior to cryopreservation

From: Bovine sperm selection procedure prior to cryopreservation for improvement of post-thawed semen quality and fertility

Cow

History of failed reproduction

Sire

Pregnancy

Heifer

Japanese Black #1

None

Bull #1

Yes

Japanese Black #2

None

Bull #2

Yes

Japanese Black #3

None

Bull #1

Yes

Japanese Black #4

None

Bull #2

Yes

Repeat breeder

Holstein #1

2 × ET, 2 × AI

Bull #1

Yes

Holstein #2

2 × ET, 3 × AI

Bull #2

Yes

Holstein #3

2 × ET, 2 × AI

Bull #1

Yes

Holstein #4

2 × AI

Bull #2

No

Holstein #4

3 × AI

Bull #1

Yes

Holstein #5

2 × ET, 3 × AI

Bull #1

Yes

Holstein #6

4 × AI

Bull #1

Yes

Holstein #7

2 × ET, 2 × AI

Bull #2

Yes

Holstein #8

4 × AI

Bull #2

Yes

  1. ET embryo transfer, AI artificial insemination using conventional frozen semen
  2. AI for Holstein #4 had been performed twice; first AI resulted in nonpregnancy, second AI achieved pregnancy
  3. Pregnancy rates of Japanese Black and Holstein cows (n = 12) inseminated with pre-freeze selected sperm cells: Bull #1 = 100%, n = 7; Bull #2 = 83.3%, n = 6, Total pregnancy rate = 92.3%
  4. Pregnancy rates of control Japanese Black cows inseminated with conventionally prepared semen from the 2 sires; Bull #1 = 59.2%, n = 76; Bull #2 = 44.4%, n = 36, Total pregnancy rate = 54.5%
  5. Values between SSTR and conventional straws differ significantly at P < 0.01 (Chi-squared test)