Evaluation of the hypothalamus-pituitary axis response to exogenous GnRH, estradiol benzoate, And LH during the postpartum period in Nellore cows

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dc.contributor.authorPinheiro, Vinícius G.
dc.contributor.authorCury, José Renato L. M.
dc.contributor.authorSatrapa, Rafael A.
dc.contributor.authorTrinca, Luzia A.
dc.contributor.authorLoureiro, Bárbara
dc.contributor.authorBarros, Ciro M.
dc.contributor.institutionUniversidade Estadual Paulista (Unesp)
dc.date.accessioned2014-05-27T11:28:40Z
dc.date.available2014-05-27T11:28:40Z
dc.date.issued2013-03-15
dc.description.abstractThe objective was to evaluate when the LH reserve was re-established in postpartum Nellore (Bos indicus) cows by evaluating the response of the hypothalamic-pituitary axis responsiveness to exogenous GnRH or estradiol benzoate (EB). Additionally, we tested the influence of dietary supplementation (SUPL) and calf removal (CR) on the duration of postpartum anestrus. Ninety multiparous lactating Nellore cows were randomly assigned to eight groups. The EB and GnRH groups received 1.0 mg EB (N = 7), and 50 μg lecireline (N = 16), respectively. Additional cows were given the same hormones, and subjected to either nutritional supplementation (EB-SUPL, N = 9; GnRH-SUPL, N = 16), or calf removal at 72 hours after calving (EB-CR, N = 4; GnRH-CR, N = 13). The remaining two groups were the LH (12.5 mg, N = 14) and control groups (saline, N = 11). Hormones were administered weekly from 7 (±5) days postpartum to first ovulation (detection of a CL during a weekly ultrasonographic examination). Blood samples were collected just before and 2 hours (GnRH, LH, and control groups) or 18 hours (EB groups) after hormone or saline (control) administration. Ovulation occurred as early as 15 days postpartum in the GnRH group. The mean ± SEM intervals (days) from calving to first ovulation were EB, 87.7 ± 4.2; EB-CR, 20.3 ± 1.2; EB-SUPL, 60.3 ± 3.2; GnRH, 40.4 ± 2.1; GnRH-CR, 21.0 ± 1.1; GnRH-SUPL, 26.4 ± 1.1; LH, 35.6 ± 1.1; and control, 60.9 ± 2.1. We concluded that there was sufficient LH in the pituitary gland (of Nellore cows) from the second week postpartum to induce ovulation in response to exogenous GnRH. Additionally, calf removal and nutritional supplementation reduced, by 2 to 4 weeks, the interval from calving to an LH increase and ovulation induced by GnRH or EB. © 2013.en
dc.description.affiliationDepartment of Pharmacology Institute of Bioscience University of São Paulo State, Botucatu, São Paulo
dc.format.extent797-802
dc.identifierhttp://dx.doi.org/10.1016/j.theriogenology.2012.12.006
dc.identifier.citationTheriogenology, v. 79, n. 5, p. 797-802, 2013.
dc.identifier.doi10.1016/j.theriogenology.2012.12.006
dc.identifier.issn0093-691X
dc.identifier.scopus2-s2.0-84874298653
dc.identifier.urihttp://hdl.handle.net/11449/74836
dc.language.isoeng
dc.relation.ispartofTheriogenology
dc.relation.ispartofjcr2.136
dc.rights.accessRightsAcesso restrito
dc.sourceScopus
dc.subjectAnestrus
dc.subjectBos indicus
dc.subjectGnRH
dc.subjectLH
dc.subjectNellore
dc.subjectPostpartum
dc.subjectdrug derivative
dc.subjectestradiol
dc.subjectestradiol 3-benzoate
dc.subjectestradiol benzoate
dc.subjectgonadorelin
dc.subjectluteinizing hormone
dc.subjectanimal
dc.subjectanimal food
dc.subjectbody weight
dc.subjectcattle
dc.subjectcontrolled clinical trial
dc.subjectcontrolled study
dc.subjectdrug effect
dc.subjectfemale
dc.subjecthistology
dc.subjecthypothalamus hypophysis system
dc.subjectmetabolism
dc.subjectovulation
dc.subjectphysiology
dc.subjectpuerperium
dc.subjectrandomized controlled trial
dc.subjectAnimal Feed
dc.subjectAnimals
dc.subjectBody Weight
dc.subjectCattle
dc.subjectEstradiol
dc.subjectFemale
dc.subjectGonadotropin-Releasing Hormone
dc.subjectHypothalamo-Hypophyseal System
dc.subjectLuteinizing Hormone
dc.subjectOvulation
dc.subjectPostpartum Period
dc.titleEvaluation of the hypothalamus-pituitary axis response to exogenous GnRH, estradiol benzoate, And LH during the postpartum period in Nellore cowsen
dc.typeArtigo
dcterms.licensehttp://www.elsevier.com/about/open-access/open-access-policies/article-posting-policy
unesp.author.orcid0000-0003-1106-8505[4]
unesp.campusUniversidade Estadual Paulista (Unesp), Instituto de Biociências, Botucatupt

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