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dc.contributor.authorWiltbank, Milo Charles
dc.contributor.authorBaez, Giovanni
dc.contributor.authorGarcia Guerra, Alvaro
dc.contributor.authorToledo, Mateus Zucato
dc.contributor.authorMonteiro, Pedro Leopoldo J.
dc.contributor.authorMelo, Leonardo F
dc.contributor.authorOchoa, Julian C.
dc.contributor.authorSantos, José Eduardo
dc.contributor.authorSartori, Roberto
dc.date.accessioned2021-12-01T23:29:14Z
dc.date.available2021-12-01T23:29:14Z
dc.date.issued2016-04-22
dc.identifier.urihttp://repositorio.ufps.edu.co/handle/ufps/1637
dc.description.abstractLoss of pregnancy can occur at many different stages of gestation and for a variety of causes but clearly produces a negative impact for reproductive and economic performances of dairy herds. This review describes four pivotal periods for pregnancy loss during the first trimester of gestation and discusses possible causes for pregnancy failure during these periods. The first period occurs during the first week after breeding with lack of fertilization and death of the early embryo producing major losses in pregnancy, particularly under specific environmental and hormonal conditions. In general, 20%–50% of high-producing lactating dairy cows have already experienced pregnancy loss during the first week of gestation with methods to decrease pregnancy loss during this period targeting improved oocyte quality by alleviating heat stress, inflammatory diseases, and body condition loss, and by increasing progesterone concentrations during preovulatory follicle development. The second pivotal period, from Days 8 to 27, encompasses embryo elongation and the classical “maternal recognition of pregnancy” period with losses averaging ∼30% but with surprising variation between farms (25%–41%). Maintenance of the CL of pregnancy is produced by the embryonic signal interferon-tau and alteration in uterine secretory patterns of prostaglandins F2α, E1, and E2. Failures or delays in trophoblast elongation and/or embryonic development result in loss of pregnancy during the second pivotal period possibly due to suboptimal histotroph. The third pivotal period is during the second month of pregnancy, Days 28 to 60, with losses of ∼12% based on a summary of published results from more than 20,000 pregnancies in high-producing dairy cows. Delays or defects in development of the chorioallantoic placentomes or embryo result in CL regression or embryo death during this pivotal period. Finally, a fourth period during the third month of pregnancy has reduced pregnancy losses (∼2%), compared with the first three periods but can be elevated in some cows, particularly in those carrying twins in the same uterine horn. Thus, there are varied causes for pregnancy losses during each pivotal period that correspond to key physiological changes in the embryo, uterine environment, and ovary. Similarly, strategies to reduce these losses are likely to require a multifaceted approach using rational methods that target the critical physiology in each pivotal period.eng
dc.format.extent3 páginasspa
dc.format.mimetypeapplication/pdfspa
dc.language.isoengspa
dc.publisherTheriogenologyspa
dc.relation.ispartofTheriogenology ISSN: 0093-691X, 2016 vol:86 fasc: 1 págs: 239 - 253, DOI:10.1016/j.theriogenology.2016.04.037
dc.rights2016 Elsevier Inc. All rights reserved.eng
dc.sourcehttps://www.sciencedirect.com/science/article/abs/pii/S0093691X16300760?via%3Dihub#kwrds0010spa
dc.titlePivotal periods for pregnancy loss during the first trimester of gestation in lactating dairy cowseng
dc.typeArtículo de revistaspa
dc.identifier.doi10.1016/j.theriogenology.2016.04.037
dc.publisher.placeEstados Unidosspa
dc.relation.citationeditionVol. 86, No. 1 (2016)spa
dc.relation.citationendpage253spa
dc.relation.citationissue1 (2016)spa
dc.relation.citationstartpage239spa
dc.relation.citationvolume86spa
dc.relation.citesWiltbank, M. C., Baez, G. M., Garcia-Guerra, A., Toledo, M. Z., Monteiro, P. L. J., Melo, L. F., Ochoa, J. C., Santos, J. E. P. y Sartori, R. (2016). Pivotal periods for pregnancy loss during the first trimester of gestation in lactating dairy cows. Theriogenology, 86(1), 239–253. https://doi.org/10.1016/j.theriogenology.2016.04.037
dc.relation.ispartofjournalTheriogenologyspa
dc.rights.accessrightsinfo:eu-repo/semantics/restrictedAccessspa
dc.subject.proposalBlastocysteng
dc.subject.proposalDairy cattleeng
dc.subject.proposalPregnancy losseng
dc.type.coarhttp://purl.org/coar/resource_type/c_6501spa
dc.type.contentTextspa
dc.type.driverinfo:eu-repo/semantics/articlespa
dc.type.redcolhttp://purl.org/redcol/resource_type/ARTspa
oaire.accessrightshttp://purl.org/coar/access_right/c_14cbspa
oaire.versionhttp://purl.org/coar/version/c_970fb48d4fbd8a85spa
dc.type.versioninfo:eu-repo/semantics/publishedVersionspa


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