Diferenças sazonais no padrão endócrino e ovariano do ciclo estral de novilhas bos taurus indicus (Nelore)
Autor(a) principal: | |
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Data de Publicação: | 2012 |
Outros Autores: | , |
Tipo de documento: | Artigo |
Idioma: | eng por |
Título da fonte: | Repositório Institucional da UNESP |
Texto Completo: | http://www.revistas.usp.br/bjvras/article/view/40172 http://hdl.handle.net/11449/74010 |
Resumo: | Estrous cycle of eight Nelore heifers were evaluated during different seasons of the year (autumn n=11; winter n=8; spring n=9 and summer n=9) with daily count and measurement of follicles ≥3mm, blood was collected every 12h for LH and progesterone (P4), and after estrous every 3h for LH peak. Five ovariectomized heifers were injected with 17β-estradiol (2μg/kg) every season and blood samples collected every 3h (for 30h) thereafter for LH quantification. The monthly percent body weight difference (Δ%) did not vary among seasons. P4 concentration was higher (p<0.01) and follicle number lower during autumn and summer compared to winter and spring. During winter there were more estrous cycles with three and during summer only cycles with two follicular waves (p<0.01). As LH secretion did not vary despite P4 concentration and as there was negative correlation between higher P4 values and daily percentile variation of photoperiod (Δ%, p<0.01; r= -0.45) it is possible to suppose that there is seasonal variation on luteal cell sensitivity to LH. In the ovariectomized Nelore heifers, the LH basal concentration (without estradiol stimulus, p=0.02) and the LH response to estradiol (p<0.01) were lower during summer, leading to the hypothesis that there is seasonal variation of hypothalamic sensitivity to estradiol. According to the present experiment there are suggestions of seasonal reproduction in Nelore heifers. |
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Diferenças sazonais no padrão endócrino e ovariano do ciclo estral de novilhas bos taurus indicus (Nelore)Seasonal differences in endocrine and ovarian patterns of bos taurus indicus (Nelore) heifers estrous cyclesSeasonal. estradiol. luteinizing hormone. ovarian follicle. progesteroneBos indicusBos taurusEstrous cycle of eight Nelore heifers were evaluated during different seasons of the year (autumn n=11; winter n=8; spring n=9 and summer n=9) with daily count and measurement of follicles ≥3mm, blood was collected every 12h for LH and progesterone (P4), and after estrous every 3h for LH peak. Five ovariectomized heifers were injected with 17β-estradiol (2μg/kg) every season and blood samples collected every 3h (for 30h) thereafter for LH quantification. The monthly percent body weight difference (Δ%) did not vary among seasons. P4 concentration was higher (p<0.01) and follicle number lower during autumn and summer compared to winter and spring. During winter there were more estrous cycles with three and during summer only cycles with two follicular waves (p<0.01). As LH secretion did not vary despite P4 concentration and as there was negative correlation between higher P4 values and daily percentile variation of photoperiod (Δ%, p<0.01; r= -0.45) it is possible to suppose that there is seasonal variation on luteal cell sensitivity to LH. In the ovariectomized Nelore heifers, the LH basal concentration (without estradiol stimulus, p=0.02) and the LH response to estradiol (p<0.01) were lower during summer, leading to the hypothesis that there is seasonal variation of hypothalamic sensitivity to estradiol. According to the present experiment there are suggestions of seasonal reproduction in Nelore heifers.Curso de Medicina Veterinária Universidade Estadual Paulista Júlio de Mesquita Filho, Araçatuba-SPCurso de Medicina Veterinária Universidade Estadual Paulista Júlio de Mesquita Filho, Araçatuba-SPUniversidade Estadual Paulista (Unesp)Corte Junior, Anivaldo Olivio [UNESP]Navarrete, Bruno José Ferreira [UNESP]Nogueira, Guilherme de Paula [UNESP]2014-05-27T11:27:24Z2014-05-27T11:27:24Z2012-12-01info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/article46-56application/pdfhttp://www.revistas.usp.br/bjvras/article/view/40172Brazilian Journal of Veterinary Research and Animal Science, v. 49, n. 1, p. 46-56, 2012.1413-95961678-4456http://hdl.handle.net/11449/740102-s2.0-848725868882-s2.0-84872586888.pdf6926188473133379Scopusreponame:Repositório Institucional da UNESPinstname:Universidade Estadual Paulista (UNESP)instacron:UNESPengporBrazilian Journal of Veterinary Research and Animal Science0,2250,225info:eu-repo/semantics/openAccess2024-09-04T19:15:38Zoai:repositorio.unesp.br:11449/74010Repositório InstitucionalPUBhttp://repositorio.unesp.br/oai/requestrepositoriounesp@unesp.bropendoar:29462024-09-04T19:15:38Repositório Institucional da UNESP - Universidade Estadual Paulista (UNESP)false |
dc.title.none.fl_str_mv |
Diferenças sazonais no padrão endócrino e ovariano do ciclo estral de novilhas bos taurus indicus (Nelore) Seasonal differences in endocrine and ovarian patterns of bos taurus indicus (Nelore) heifers estrous cycles |
title |
Diferenças sazonais no padrão endócrino e ovariano do ciclo estral de novilhas bos taurus indicus (Nelore) |
spellingShingle |
Diferenças sazonais no padrão endócrino e ovariano do ciclo estral de novilhas bos taurus indicus (Nelore) Corte Junior, Anivaldo Olivio [UNESP] Seasonal. estradiol. luteinizing hormone. ovarian follicle. progesterone Bos indicus Bos taurus |
title_short |
Diferenças sazonais no padrão endócrino e ovariano do ciclo estral de novilhas bos taurus indicus (Nelore) |
title_full |
Diferenças sazonais no padrão endócrino e ovariano do ciclo estral de novilhas bos taurus indicus (Nelore) |
title_fullStr |
Diferenças sazonais no padrão endócrino e ovariano do ciclo estral de novilhas bos taurus indicus (Nelore) |
title_full_unstemmed |
Diferenças sazonais no padrão endócrino e ovariano do ciclo estral de novilhas bos taurus indicus (Nelore) |
title_sort |
Diferenças sazonais no padrão endócrino e ovariano do ciclo estral de novilhas bos taurus indicus (Nelore) |
author |
Corte Junior, Anivaldo Olivio [UNESP] |
author_facet |
Corte Junior, Anivaldo Olivio [UNESP] Navarrete, Bruno José Ferreira [UNESP] Nogueira, Guilherme de Paula [UNESP] |
author_role |
author |
author2 |
Navarrete, Bruno José Ferreira [UNESP] Nogueira, Guilherme de Paula [UNESP] |
author2_role |
author author |
dc.contributor.none.fl_str_mv |
Universidade Estadual Paulista (Unesp) |
dc.contributor.author.fl_str_mv |
Corte Junior, Anivaldo Olivio [UNESP] Navarrete, Bruno José Ferreira [UNESP] Nogueira, Guilherme de Paula [UNESP] |
dc.subject.por.fl_str_mv |
Seasonal. estradiol. luteinizing hormone. ovarian follicle. progesterone Bos indicus Bos taurus |
topic |
Seasonal. estradiol. luteinizing hormone. ovarian follicle. progesterone Bos indicus Bos taurus |
description |
Estrous cycle of eight Nelore heifers were evaluated during different seasons of the year (autumn n=11; winter n=8; spring n=9 and summer n=9) with daily count and measurement of follicles ≥3mm, blood was collected every 12h for LH and progesterone (P4), and after estrous every 3h for LH peak. Five ovariectomized heifers were injected with 17β-estradiol (2μg/kg) every season and blood samples collected every 3h (for 30h) thereafter for LH quantification. The monthly percent body weight difference (Δ%) did not vary among seasons. P4 concentration was higher (p<0.01) and follicle number lower during autumn and summer compared to winter and spring. During winter there were more estrous cycles with three and during summer only cycles with two follicular waves (p<0.01). As LH secretion did not vary despite P4 concentration and as there was negative correlation between higher P4 values and daily percentile variation of photoperiod (Δ%, p<0.01; r= -0.45) it is possible to suppose that there is seasonal variation on luteal cell sensitivity to LH. In the ovariectomized Nelore heifers, the LH basal concentration (without estradiol stimulus, p=0.02) and the LH response to estradiol (p<0.01) were lower during summer, leading to the hypothesis that there is seasonal variation of hypothalamic sensitivity to estradiol. According to the present experiment there are suggestions of seasonal reproduction in Nelore heifers. |
publishDate |
2012 |
dc.date.none.fl_str_mv |
2012-12-01 2014-05-27T11:27:24Z 2014-05-27T11:27:24Z |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://www.revistas.usp.br/bjvras/article/view/40172 Brazilian Journal of Veterinary Research and Animal Science, v. 49, n. 1, p. 46-56, 2012. 1413-9596 1678-4456 http://hdl.handle.net/11449/74010 2-s2.0-84872586888 2-s2.0-84872586888.pdf 6926188473133379 |
url |
http://www.revistas.usp.br/bjvras/article/view/40172 http://hdl.handle.net/11449/74010 |
identifier_str_mv |
Brazilian Journal of Veterinary Research and Animal Science, v. 49, n. 1, p. 46-56, 2012. 1413-9596 1678-4456 2-s2.0-84872586888 2-s2.0-84872586888.pdf 6926188473133379 |
dc.language.iso.fl_str_mv |
eng por |
language |
eng por |
dc.relation.none.fl_str_mv |
Brazilian Journal of Veterinary Research and Animal Science 0,225 0,225 |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
46-56 application/pdf |
dc.source.none.fl_str_mv |
Scopus reponame:Repositório Institucional da UNESP instname:Universidade Estadual Paulista (UNESP) instacron:UNESP |
instname_str |
Universidade Estadual Paulista (UNESP) |
instacron_str |
UNESP |
institution |
UNESP |
reponame_str |
Repositório Institucional da UNESP |
collection |
Repositório Institucional da UNESP |
repository.name.fl_str_mv |
Repositório Institucional da UNESP - Universidade Estadual Paulista (UNESP) |
repository.mail.fl_str_mv |
repositoriounesp@unesp.br |
_version_ |
1810021385896984576 |