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Reproduction in dairy cows following progesterone insert presynchronization and resynchronization protocols.
R C Chebel1, J E P Santos, R L A Cerri
1Veterinary Medicine Teaching and Research Center, University of California-Davis, Tulare 93274, USA.
Journal of Dairy Science
|October 13, 2006
Summary
Progesterone inserts (CIDR) improved estrus cyclicity in anestrous dairy cows. Resynchronization with CIDR reduced pregnancy loss, increasing pregnancy rates at 60 days post-AI.
Area of Science:
- Reproductive endocrinology in dairy cattle
- Animal reproduction and artificial insemination
Background:
- Anestrus and suboptimal estrus detection reduce fertility in postpartum dairy cows.
- Progesterone plays a crucial role in estrous cycle regulation and pregnancy maintenance.
Purpose of the Study:
- To evaluate the impact of progesterone intravaginal inserts (CIDR) in presynchronization and resynchronization protocols on dairy cow fertility.
- To assess effects on cyclicity, estrus detection, pregnancy rates, and pregnancy loss.
Main Methods:
- 1,052 Holstein cows were assigned to control, CIDR estrus-detection (CED), or CIDR timed AI (CTAI) presynchronization treatments.
- Resynchronization treatments included no resynchronization (RCON) or CIDR insert (RCIDR) post-AI.
- Progesterone levels were monitored to assess cyclicity; pregnancy was diagnosed via ultrasound.
Main Results:
- CIDR-based presynchronization (CED and CTAI) increased the proportion of anestrous cows that resumed cyclicity by 62 days postpartum compared to controls.
- Resynchronization with CIDR (RCIDR) improved pregnancy rates at 31 days (in CED and CTAI groups) and 60 days post-first AI (in all groups) due to reduced pregnancy loss.
Conclusions:
- Presynchronization with CIDR effectively induces cyclicity in anestrous postpartum dairy cows.
- Resynchronization with CIDR reduces pregnancy loss, enhancing overall pregnancy rates to first service.
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