Herlihy, Mary M.Giordano, Julio O.Souza, Alex H.Ayres, HendersonFerreira, Roberta M.Nascimento, Anibal B.Guenther, Jerry N.Gaska, Jerry M.Kacuba, S. J.Crowe, Mark A.Butler, Stephen T.Wiltbank, Milo C.2022-02-282022-02-282012-12Herlihy, M. M. vd. (2012). "Presynchronization with Double-Ovsynch improves fertility at first postpartum artificial insemination in lactating dairy cows". Journal of Dairy Science, 95(12), 7003-7014.0022-03021525-3198https://doi.org/10.3168/jds.2011-5260https://www.sciencedirect.com/science/article/pii/S0022030212007047http://hdl.handle.net/11452/24724The objective of this study was to compare circulating progesterone (P4) profiles and pregnancies per AT (P/AI) in lactating dairy cows bred by timed artificial insemination (TAT) following Ovsynch-56 after 2 different presynchronization protocols: Double-Ovsynch (DO) or Presynch-Ovsynch (PS). Our main hypothesis was that DO would increase fertility in primiparous cows, but not in multiparous cows. Within each herd (n = 3), lactating dairy cows (n = 1,687; 778 primiparous, 909 multiparous) were randomly assigned to DO [n = 837; GnRH-7d-PGF(2 alpha)-3d-GnRH-7d-Ovsynch-56 (GnRH-7d-PGF(2 alpha)-56h-GnRH-16hTAI)] or PS (n = 850; PGF(2 alpha)-14d-PGF(2 alpha)-12d-Ovsynch-56). In 1 herd, concentrations of P4 were determined at the first GnRH (GnRH1) of Ovsynch-56 and at d 11 after TAI (n = 739). In all herds, pregnancy was diagnosed by palpation per rectum at 39 d. In 1 herd, the incidence of late embryo loss was determined at 74 d, and data were available on P/AI at the subsequent second service. Presynchronization with DO reduced the percentage of animals with low P4 concentrations (<0.50 ng/mL) at GnRH1 of Ovsynch-56 (5.4 VS. 25.3%, DO vs. PS). A lesser percentage of both primiparous and multiparous cows treated with DO had low P4 concentrations at GnRH1 of Ovsynch-56 (3.3 vs. 19.7%, DO vs. PS primiparous; and 8.8 vs. 31.9%, DO vs. PS multiparous). Presynchronization with DO improved P/AI at the first postpartum service (46.3 vs. 38.2%, DO vs. PS). Statistically, a fertility improvement could be detected for primiparous cows treated with DO (52.5 vs. 42.3%, DO vs. PS, primiparous), but only a tendency could be detected in multiparous cows (40.3 vs. 34.3%, DO vs. PS, multiparous), consistent with our original hypothesis. Presynchronization treatment had no effect on the incidence of late embryo loss after first service (8.5 vs. 5.5%, DO vs. PS). A lower body condition score increased the percentage of cows with low P4 at GnRH1 of Ovsynch-56 and reduced fertility to the TAI. In addition, P4 concentration at d 11 after TAI was reduced by DO. The method of presynchronization at first service had no effect on P/AI at the subsequent second service (34.7 vs. 36.5%, DO vs. PS). Thus; presynchronization with DO induced cyclicity in most anovular cows and improved fertility compared with PS, suggesting that DO could be a useful reproductive management protocol for synchronizing first service in commercial dairy herds.eninfo:eu-repo/semantics/openAccessAgricultureFood science & technologyPresynchronizationOvsynchDairy cowPregnancy rateBody conditionReproductive-performanceOvulatory follicleHormone injectionPregnancy ratesMilk-productionRisk-factorsSynchronizationAnimaliaBosAnimalsCattleEstrus synchronizationFemaleFertilityInsemination, artificialLactationOvaryParityPregnancyProgesteroneArticle0003111929000192-s2.0-8486949631770037014951223021750Agriculture, dairy & animal scienceFood science & technologyArtificial Insemination; Estrus; Estrus SynchronizationProgesteroneAnimalAnimal diseaseArticleArtificial inseminationBloodCattleDrug effectEchographyEstrus cycleFemaleFertilityLactationMethodologyOvaryParityPhysiologyPregnancy