An investigation of the time period within which frozen-thawed semen delivers a high conception rate in lactating dairy cows
We determined the length of time within which frozen-thawed semen delivered a high conception rate in present-day lactating dairy cows. The cows utilized were a total 100 milking Holstein-Friesian cows kept in tie-stall style farms. We carried out artificial insemination (AI) during the periovulator...
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| Main Authors: | , , |
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| Format: | Book |
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The Society for Reproduction and Development,
2020-03-01T00:00:00Z.
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| Summary: | We determined the length of time within which frozen-thawed semen delivered a high conception rate in present-day lactating dairy cows. The cows utilized were a total 100 milking Holstein-Friesian cows kept in tie-stall style farms. We carried out artificial insemination (AI) during the periovulatory period at a predicted time based on ovulation, and checked ovulation at 6-h intervals after AI. The period from AI to ovulation ranged from 48 h (i.e., 48 h before ovulation) to -12 h (i.e., 12 h after ovulation). High conception rates averaging 63.0% were obtained by carrying out AI > 6-30 h before ovulation, significantly higher than the conception rates of 30.0% (P < 0.05) and 26.9% (P < 0.01) from AI carried out earlier than 30 h before ovulation and later than 6 h before ovulation, respectively. It was concluded that frozen-thawed semen delivers a conception rate of ≥ 60% for > 24-30 h after AI, and that a conception rate of ≥ 60% can be achieved by carrying out AI 6-30 h before ovulation using frozen-thawed semen. |
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| Item Description: | 0916-8818 1348-4400 10.1262/jrd.2019-130 |