The Effect of Second Prostaglandin F2α Application with the Presynchronization Protocol on Fertility in Simmental Cows
Year: 2026
Type: article
Abstract: The objective of the study was to evaluate the effect of an additional PGF2α injection 24 hours after the first PGF2α in the timed AI Ovsynch protocol on the pregnancy/artificial insemination (P/AI) rate of Simmental cows presynchronized with PG-3-G. The study was conducted on a commercial farm with 103, lactating Simmental cows. Animals were randomly divided into two groups (1) PG-3-G Group (n=56): PGF2α on day 0; GnRH on day 3; Ovsynch initiation after on day 10. (2) PG-3-PG Group (n=47): Second PGF2αaddition 24 hours apart before timed AI to PG-3-G protocol. Parity, milk yield, and days in milk (DIM) were compared between the synchronization protocols. The pregnancy rates in the postpartum first and ≥2 TAI were similar between groups (p=0.462 and p=0.566, respectively). There were no statistical differences in the P/AI rates between groups 51.78% (29/56) and 51.06% (27/47), respectively. Multiparous cows revealed numerically higher pregnancy rates than the primiparous cows. However, P/AI results did not differ between groups (p=0.942). The mean preovulatory follicle diameter was 1.71±0.15 cm in the PG-3-G group, and 1.79±0.15 cm in the PG-3-PG group and the difference between groups was significant (p=0.047). In conclusion, administration of a second PGF2α injection to the protocol improved the P/AI numerically in multiparous cows, and preovulatory follicle size. Nevertheless, those findings need to be evaluated by conductinga larger study with a larger sample size.
Source: Van veterinary journal
Institutions: Cukurova University, Afyon Kocatepe University
Language: English
Subfield: Agronomy and Crop Science
Domain: Life Sciences
SDG: Zero hunger
Open Access status: diamond
OpenAlex ID: W7171506622