OVSYNCH-BASED SYNCHRONIZATION PROTOCOLS ON FIRST-SERVICE PREGNANCY RATES IN PRIMIPAROUS SIMMENTAL COWS
DOI:
https://doi.org/10.26873/SVR-2344-2026Keywords:
dairy cows, estrus response, Ovsynch, PGF₂α, pregnancy rate, synchronization protocolsAbstract
This study compared the effects of three Ovsynch-based synchronization protocols on first-service pregnancy rates in primiparous Simmental cows under field conditions. Materials and Methods: A total of 69 primiparous Simmental cows meeting the predefined inclusion criteria were randomly assigned to three groups (n = 23/group): PGF₂α pre-treatment followed by Ovsynch (Group 1), classical Ovsynch (Group 2), and Ovsynch with an additional PGF₂α administration on day 8 (Group 3). All animals underwent timed artificial insemination, and pregnancy diagnosis was performed by transrectal ultrasonography 30 days post-insemination. Results: Pregnancy rates were 56.5%, 43.5%, and 34.8% for Groups 1, 2, and 3, respectively, with no statistically significant differences among groups (p > 0.05). Estrus response following the first hormonal administration was observed in 21.7%, 17.4%, and 4.3% of animals, respectively, also without significant differences (p > 0.05). Conclusion: No statistically significant differences were observed among the synchronization protocols with respect to pregnancy rates or estrus response (p > 0.05). The results should be interpreted in light of the pilot nature of the study.
References
Roelofs J, Lopez-Gatius F, Hunter RHF, Van Eerdenburg FJCM, Hanzen CH (2010). When is a cow in estrus? Clinical and practical aspects. Theriogeno-logy, 74: 327–344. https://doi.org/10.1016/j.theriogenology.2010.02.016
Akçay A, Abay M, Çelik Gürbulak E (2022). The meta-analysis of conception rates of dairy cattle treated with the Ovsynch proto-col in Türkiye. Kafkas Univ. Vet. Fak. Derg., 28(4). 10.9775/kvfd.2022.27628
Boudaoud A (2023). Timed artificial insemination protocols in dairy cattle: Functioning, shortcomings, and improvements. Czech J. Anim. Sci., 68: 231–244. DOI: 10.17221/208/2022-CJAS
Santos VG, Carvalho PD, Maia C, Carneiro B, Valenza A, Crump PM, Fricke PM (2016). Adding a second prostaglandin F2α treat-ment to but not redu-cing the duration of a PRID-Synch protocol increases fertility after resynchronization of ovulation in lactating Holstein cows. J. Dairy Sci., 99: 3869–3879. https://doi.org/10.3168/jds.2015-10557
Borchardt S, Pohl A, Carvalho PD, Fricke PM, Heuwieser W (2018). Effect of adding a second prostaglandin F2α injection during the Ovsynch protocol on luteal regression and fertility in lactating dairy cows: A meta-analysis. J. Dairy Sci., 101: 8566–8571. https://doi.org/10.3168/jds.2017-14191
Pursley JR, Mee MO, Wiltbank MC (1995). Synchronization of ovulation in dairy cows using PGF2α and GnRH. Theriogenology, 44: 915–923. https://doi.org/10.1016/0093-691X(95)00279-H
Moreira F, De la Sota RL, Diaz T, Thatcher WW (2000). Effect of day of the estrous cycle at the initiation of a timed artificial in-semination protocol on reproductive responses in dairy heifers. J. Dairy Sci., 78: 1568–1576. https://doi.org/10.2527/2000.7861568x
Brusveen DJ, Souza AH, Wiltbank MC (2009). Effects of additional pro-staglandin F2α and estradiol-17β during Ovsynch in lacta-ting dairy cows. J. Dairy Sci., 92: 1412–1422. https://doi.org/10.3168/jds.2008-1289
Wiltbank MC, Baez GM, Cochrane F, Barletta RV, Trayford CR, Joseph RT (2015). Effect of a second treatment with prostaglandin F2α during the Ovsynch protocol on luteolysis and pregnancy in dairy cows. J. Dairy Sci., 98: 8644–8654. https://doi.org/10.3168/jds.2015-9353
Dirandeh E, Roodbari AR, Gholizadeh M, Deldar H, Masoumi R, Kazemi-fard M, Colazo MG (2015). Administration of pro-staglandin F2α 14 d before initiating a G6G or a G7G timed artificial insemination protocol increased circulating progesterone prior to artificial insemination and reduced pre-gnancy loss in multiparous Holstein cows. J. Dairy Sci., 98: 5414–5421. https://doi.org/10.3168/jds.2015-9417
Carvalho PD, Fuenzalida MJ, Ricci A, Souza AH, Barletta RV, Wiltbank MC, Fricke PM (2015). Modifications to Ovsynch improve fertility during resynchronization: Evaluation of presynchronization with gonadotropin-releasing hormone 6 d before initiation of Ovsynch and addition of a second prostaglandin F2α treatment. J. Dairy Sci., 98: 8741–8752. https://doi.org/10.3168/jds.2015-9719
Heidari F, Dirandeh E, Pirsaraei ZA, Colazo MG (2017). Modifications of the G6G timed-AI protocol improved pregnancy per AI and reduced pre-gnancy loss in lactating dairy cows. Animal, 11: 2002-2009. https://doi.org/10.1017/S1751731117000520
Edmonson AJ, IJ Lean, LD Weaver, T Farver, G Webster (1989). A Body Condition Scoring Chart for Holstein Dairy Cows. J Dairy Sci 72:68-78.
The jamovi project (2025). jamovi (Version 2.7) [Computer software]. Retrieved from https://www.jamovi.org
R Core Team (2025). R: A language and environment for statistical computing (Version 4.5) [Computer software]. Retrieved from https://cran.r-project.org
Barletta RV, Carvalho PD, Santos VG, Melo LF, Consentini CE, Netto AS, Fricke PM (2018). Effect of dose and timing of pro-staglandin F2α treatments during a Resynch protocol on luteal regression and fertility to timed artificial insemination in lactating Holstein cows. J. Dairy Sci., 101: 1730–1736. https://doi.org/10.3168/jds.2017-13628
Stevenson JS, Sauls JA, Mendonça LGD, Voelz BE (2018). Dose frequency of prostaglandin F2α administration to dairy cows exposed to presynchroni-zation and either 5- or 7-day Ovsynch program durations: Ovulatory and luteolytic risks. J. Dairy Sci., 101: 9575–9590. https://doi.org/10.3168/jds.2018-14653
Yousuf MR, Martins JPN, Ahmad N, Nobis K, Pursley JR (2016). Presynchronization of lactating dairy cows with PGF2α and GnRH simulta-neously, 7 days before Ovsynch have similar outcomes compared to G6G. Theriogenology, 86: 1607–1614. https://doi.org/10.1016/j.theriogenology.2016.05.021
Martins JPN, Acevedo MJT, Cunha TO, Piterini C, Pursley JR (2017). The effect of presynchronization with prostaglandin F2α and gonadotropin-releasing hormone simultaneously, 7 d before Ovsynch, compared with Presynch-10/Ovsynch on luteal function and first-service pregnancies per artificial insemination. J. Dairy Sci., 100: 5107–5116. https://doi.org/10.3168/jds.2016-11628
Consentini CE, Abadia T, Galindez JP, Lopes AL, Ferro PP, Pazini YE, Sartori R (2025). Fertility programs for lactating dairy cows: A novel Presynch + timed artificial insemination program (Double E-Synch) produces similar ovarian dynamics, synchronization, and fertility as Double-Ovsynch. J. Dairy Sci., 108: 4435–4447. https://doi.org/10.3168/jds.2024-25221
Ambarcıoğlu P, Mavridis D, Yazlık M, Vural R, Ok M, Gürcan S (2023). Comparison of synchronisation protocols on pregnancy rate in dairy cows and heifers: A systematic review and network meta-analysis. J. Hellenic. Vet. Med. Soc., 74(2). 10.12681/jhvms.29829
Downloads
Published
How to Cite
Issue
Section
License
Copyright (c) 2026 Yavuz Musabeşeoğlu
This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.
