Uterine involution, day and variance of first postpartum ovulation in mares treated with progesterone and estradiol-17β for 1 or 2 days postpartum

Bruemmer, J.E.; Brady, H.A.; Blanchard, T.L.

doi:10.1016/s0093-691x(01)00703-8

Cited by 14 publications

(10 citation statements)

References 13 publications

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“…Mares undergoing estrus suppression from sex steroid or GnRH antagonist administration have been observed to ovulate with a minimal fold change in LH (46,47). However, the typical preovulatory surge in the mare lasts from 3-5 d with a 2.2-to 3.17-fold change in LH that peaks after ovulation (20).…”

Section: Discussionmentioning

confidence: 99%

Biological and Anatomical Evidence for Kisspeptin Regulation of the Hypothalamic-Pituitary-Gonadal Axis of Estrous Horse Mares

Magee¹,

Foradori

Bruemmer

et al. 2009

Endocrinology

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The purpose of the present study was to evaluate the effects of kisspeptin (KiSS) on LH and FSH secretion in the seasonally estrous mare and to examine the distribution and connectivity of GnRH and KiSS neurons in the equine preoptic area (POA) and hypothalamus. The diestrous mare has a threshold serum gonadotropin response to iv rodent KiSS decapeptide (rKP-10) administration between 1.0 and 500 microg. Administration of 500 microg and 1.0 mg rKP-10 elicited peak, mean, and area under the curve LH and FSH responses indistinguishable to that of 25 microg GnRH iv, although a single iv injection of 1.0 mg rKP-10 was insufficient to induce ovulation in the estrous mare. GnRH and KiSS-immunoreactive (ir) cells were identified in the POA and hypothalamus of the diestrous mare. In addition, KiSS-ir fibers were identified in close association with 33.7% of GnRH-ir soma, suggesting a direct action of KiSS on GnRH neurons in the mare. In conclusion, we are the first to reveal a physiological role for KiSS in the diestrous mare with direct anatomic evidence by demonstrating a threshold-like gonadotropin response to KiSS administration and characterizing KiSS and GnRH-ir in the POA and hypothalamus of the diestrous horse mare.

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Section: Discussionmentioning

confidence: 99%

Biological and Anatomical Evidence for Kisspeptin Regulation of the Hypothalamic-Pituitary-Gonadal Axis of Estrous Horse Mares

Magee¹,

Foradori

Bruemmer

et al. 2009

Endocrinology

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“…De forma semelhante, altas taxas de prenhez (81 a 89%) foram obtidas por outros pesquisadores utilizando o primeiro estro pós-parto (BRUEMMER; BRADY; BLANCHARD, 2002). Portanto, apesar do pequeno número de animais utilizados, os resultados de fertilidade obtidos no presente experimento demonstram que bons índices de prenhez podem ser obtidos quando o primeiro estro pós parto é utilizado.…”

Section: Discussionunclassified

“…Baixas taxas de concepção têm sido atribuídas à éguas acasaladas em até 10 dias pós-parto (LOY, 1980), possivelmente devido ao incompleto processo de involução uterina (GYGAX; GANJAM; KENNEY, 1979;STEVEN et al, 1979 Outros autores sugerem o acasalamento depois dos 10 dias após o parto, com o intuito de aumentar o tempo para o processo de involução uterina e permitir o reparo histológico, garantindo que o embrião esteja presente no útero após este período (14 dias pós-parto), melhorando assim as chances de sucesso reprodutivo (LOY et al, 1982;MCKINNON et al, 1988;BRADY;BLANCHARD, 2002). Desta forma, alguns autores propuseram a utilização de PGF2α 6 dias após a primeira ovulação e acasalamento no segundo estro pós-parto ou a utilização de esteroides ovarianos para retardar o início do primeiro estro e ovulação pós-parto.…”

Section: Involução Uterinaunclassified

“…Este aumento abrupto nas concentrações de fluido intrauterino entre d1 e d2 também foi observado pelos mesmos autores, os quais sugeriram que este fenômeno ocorre devido a um influxo fisiológico associado ao processo de involução uterina, não se tratando de fluido residual da placenta. A presença de fluido intrauterino tem sido descrita em até 9 (GÜNDÜZ; KAŞIKCI; KAYA, 2008), 10 (BRUEMMER; BRADY; BLANCHARD, 2002), 15 (MCKINNON et al, 1988 ou 16 dias (GRIFFIN; GINTHER, 1991a) pós-parto em éguas ou em até 18 dias pós-parto em jumentas (DADARWAL et al, 2004). De forma semelhante, no presente estudo 50% (5/10) dos animais não apresentou acúmulo de fluido após 10 dias, assim como não foi observado acúmulo de fluido após os 16 dias pós-parto em nenhum animal.…”

Section: Fluido Intrauterinounclassified

“…Geralmente, menores taxas de prenhez (9 a 20%) são descritas em relação à fertilidade do primeiro estro pós-parto quando comparadas à fertilidade de ciclos estrais subsequentes (LOY, 1980;KATILA 1987;OIJALA, 1988;GINTHER, 1992). No entanto, outros autores relatam taxas de prenhez similares entre os diferentes ciclos pós-parto (CAMILLO et al, 1997;MALSCHITZKY et al, 2002), entre o primeiro estro pós-parto e ciclos de éguas não gestantes GINTHER, 1991a;CAMILLO et al, 1997) ou até mesmo altas taxas de prenhez (> 80%) em éguas inseminadas no cio do potro (BRUEMMER; BRADY; BLANCHARD, 2002). Por outro lado, maior potencial para perdas gestacionais (MERKT; GÜNZEL, 1979;BONNETT;MCKEE, 1991;GINTHER, 1992;MORRIS;ALLEN, 2002) ou menores taxas de recuperação embrionária (HUHTINEN; REILAS; KATILA, 1996) tem sido atribuídas ao primeiro estro pós-parto quando comparado a ciclos de éguas não gestantes.…”

Section: Introductionunclassified

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Avaliação da dinâmica ovariana, características uterinas, fluxo sanguíneo uterino e ovariano e concentrações séricas de progesterona em éguas no período pós-parto

Lemes¹

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Avaliação da dinâmica ovariana, características uterinas, fluxosanguíneo uterino e ovariano e concentrações séricas de progesterona em éguas no período pós-parto The aim of this study was to evaluate the characteristics of ovarian dynamics, aspects of the uterine involution process and characteristics of uterine and ovarian hemodynamic during the postpartum period in mares (n = 10). Thus, the content presented in this thesis is divided into two chapters. In the first chapter, the aspects of the uterine involution process and characteristics of endometrial and mesometrial vascularization were evaluated. A rapid reduction (P<0,05) in uterine diameter was observed during the first 7 days postpartum, with subsequent decrease in the rate of uterine involution, and this process was completed in about 21 days for formerly nongravid horn (CNG) and 24 days for the formerly gravid horn (CG). For intrauterine fluid accumulations, an increase (P<0,05) was observed between days 1 and 2 postpartum (d1 and d2), with a significant reduction between d4 and d7, and no amount of fluid collections was observed in the animals after d16 or after the third day post-ovulation (D3). No differences (P>0,05) was observed between the uterine horns (CG and CNG) in relation to vascular perfusion characteristics. In this context, an increase (P<0,05) in the endometrial vascularity scores was observed between d1 and d4, remaining similar until d13, as well as an increase (P<0,05) in mesometrial vascularization occurred between d1 and d2. However, a reduction (P<0,05) in scores of mesometrial vasculature was observed from d2 to d10. After ovulation, an increase of endometrial vascularization was observed from D0 to D5, with reduction in scores from D5 to D11 and a further increase between D11 and D14. Similarly, the pattern of mesometrial vascularization was similar to that observed in the endometrium. In the second chapter, follicular development and vascularization were assessed during the first postpartum estrus, as well the characteristics of development and vascular perfusion of the corpus luteum (CL) and serum progesterone (P4) during the 16 days after the first postpartum ovulation.Additionally, the animals were divided into two groups: the group early (ovulation before the d10) or late (ovulation after d10). With regard to follicular development, no difference was observed between groups in days relative to the first postpartum ovulation, however, when evaluated on the day of parturition, differences were observed between groups. In this respect, the early group had a larger diameter (P<0,05) of the dominant follicle (F1) each day in the early postpartum period (d1-d7) and had a greater number of follicles (P<0,05) in the > 25 mm class during the first days postpartum (d1-d3). Additionally, the animals in the late group showed a greater number of follicles (P<0,05) in the 20-25 mm class during early postpartum period (d4-d7). Regarding the characteristics of vascular perfusion, no difference (P>0,05) was observed between groups regardin...

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Breeding the Post-Partum Mare

Matthews¹,

Samper²

2009

Equine Breeding Management and Artificial Insemination

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Uterine involution, day and variance of first postpartum ovulation in mares treated with progesterone and estradiol-17β for 1 or 2 days postpartum

Cited by 14 publications

References 13 publications

Biological and Anatomical Evidence for Kisspeptin Regulation of the Hypothalamic-Pituitary-Gonadal Axis of Estrous Horse Mares

Biological and Anatomical Evidence for Kisspeptin Regulation of the Hypothalamic-Pituitary-Gonadal Axis of Estrous Horse Mares

Avaliação da dinâmica ovariana, características uterinas, fluxo sanguíneo uterino e ovariano e concentrações séricas de progesterona em éguas no período pós-parto

Breeding the Post-Partum Mare

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