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Title: | An investigation of the time period within which frozen-thawed semen delivers a high conception rate in lactating dairy cows |
Authors: | Sumiyoshi, Toshiaki Tanaka, Tomomi Kamomae, Hideo |
Keywords: | Artificial insemination (AI) Conception rate Dairy cows Frozen semen Ovulation |
Issue Date: | 2020 |
Series/Report no.: | Journal of reproduction and development;Vol. 66, No. 03 .- P.277-280 |
Abstract: | 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 (Al) during the periovulatory period at a predicted time based on ovulation, and checked ovulation at 6-h intervals after Al. 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 Al 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. |
URI: | https://dspace.ctu.edu.vn/jspui/handle/123456789/71161 |
ISSN: | 0916-8818 |
Appears in Collections: | The journal of reproduction and development |
Files in This Item:
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Your IP: 18.222.161.245 |
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