Abstract
Background: Reproductive efficiency affects dairy cow profitability. Ovarian function in postpartum (P.P.) has beenbetter understood using ultrasound and hormonal assays. Optimizing ovulation synchronization and carefully timingartificial insemination (TAI) can greatly enhance reproductive rates in dairy cows.Aim: This experiment was designed to investigate the reproductive performance and ovarian activity in earlypostpartum lactating dairy cows using the Presynch-PGF2α, Ovsynch protocol, and TAI.Methods: Randomly the cows were assigned to a control group and a treatment group, based on the chronologicalorder of their calving date. On day 14 P.P., both groups received two cloprostenol treatments, 14 days apart.Ultrasonographic inspections were conducted on day 14 to check ovarian activity and uterine contents. On day 11, afterpresynchronization, cows in the treatment group were given 100 μg IM. of cystorelin, followed by a luteolytic dose of500 μg IM., cloprostenol on day 7, and a second dose of cystorelin on day 8 (36 hours later). After the second cystorelininjection by 16–20 hours, cows were inseminated, while the control group had all cows displaying spontaneous estrusbetween day 0 and day 28 were artificially inseminated.Results: Ovarian activity began to improve at 82.61% on day 19 P.P., with complete recovery between days 24 and27 P.P. The second cloprostenol injection approached, causing follicular size to reach 8.41 ± 1.04 mm. After thesecond injection, ovarian activity switched from follicular to luteal, with corpus luteum rates of 23.91% and 26.1%.The presynchronized PGF2α regimen significantly enhanced ovarian activity from days 19–35 P.P. Ovulation andpregnancy rates in the Ovsynch group were 54.2% and 41.7% at the first timed artificial insemination (TAI), comparedto 54.5% and 31.8% in the control group. There was no significant impact between them; it was just high in thepresynchronized Ovsynch group. However, the P.P. period was minimized to 47–49 days till the first AI reached a41.7% pregnancy rate and 20.8% at the second AI, for an overall 62.5%.Conclusion: The current study concludes that presynchronization during preservice in clinically normal P.P. dairycows reduces P.P. duration, increases ovarian activity performance, and reduces ovarian dysfunctions from day 19 today 35 P.P., as well as improves the pregnancy rate. (PDF) Impact of presynchronization and Ovsynch on early postpartum ovarian activity and fertility of dairy cows in Libya. Available from: https://www.researchgate.net/publication/379811882_Impact_of_presynchronization_and_Ovsynch_on_early_postpartum_ovarian_activity_and_fertility_of_dairy_cows_in_Libya [accessed Oct 06 2026].