Ovarian follicular dynamics in Suffolk ewes at different periods of the year

Noël, B; Bister, JL; Paquay, R.

doi:10.1530/jrf.0.0990695

Cited by 77 publications

(32 citation statements)

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“…O dia de emergência da primeira onda folicular não foi diferente entre os dois grupos experimentais, sendo de 0,57 ± 0,53 e 0,86 ± 0,40, para os grupos controle e tratado com a gonadotrofina exógena, respectivamente, valores próximos aos obtidos por Noel et al (1993) e Leyva et al (1998).…”

Section: Resultsunclassified

Respostas endócrinas e ovarianas associadas com o folículo dominante da primeira onda folicular em ovelhas sincronizadas com CIDR ou PGF2alfa

et al. 2002

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RESUMO -Os efeitos de prostaglandina (PGF 2 a) vs CIDR e eCG (gonadotrofina coriônica eqüina) na dinâmica folicular da primeira onda e sua relação com as concentrações plasmáticas de P 4 e E 2 foram investigadas em ovelhas cíclicas. Foram utilizadas 14 fêmeas ovinas da raça Bergamascia; o Grupo 1 (G1) foi submetido a duas aplicações de PGF 2α e o Grupo 2 (G2), tratado com CIDR durante 14 dias, sendo que, no momento de sua retirada, administraram-se 500 UI de eCG. A dinâmica folicular ovariana foi monitorada por meio de ultrasom. Monitoraram-se todos os folículos ≥ 2mm e mapeou-se sua posição diariamente, observando-se o desenvolvimento individual de cada folículo. Desde o dia anterior à aplicação da segunda dose de PGF 2α (G1) e desde a administração de eCG (G2) até o décimo dia do ciclo estral, foram coletadas amostras de sangue para análise de P 4 e E 2 . Houve diferença significativa nas concentrações plasmáticas de P 4 e E 2 entre os tratamentos. A sincronização de estro e ovulação, utilizando CIDR + 500 UI de eCG, incrementou a quantidade de folículos recrutados, além de aumentar o diâmetro máximo e a taxa de crescimento dos folículos grandes na primeira onda folicular.Palavras-chave: dinâmica folicular, estradiol (E 2 ), ovinos, progesterona (P 4 ), ultra-sonografia Endocrine and Ovarian Response Associated with the First-Wave Follicle Dominant in Sheep Synchronized either CIDR or PGF 2αABSTRACT -The effect of prostaglandin (PGF 2 a) vs CIDR and eCG (equine chorionic gonadotrophin) on follicular dynamic of wave 1 and its relation with P 4 and E 2 plasma concentrations were investigated in cyclic ewes. Fourteen Bergamascia ewes were used, Group 1 (G1) synchronized by two i.m. injections of PGF 2α and Group 2 (G2) treated for 14 d with CIDR and 500 IU of eCG at dispositive withdrawal on day 14. Ovarian follicular dynamics were ultrasonically monitored. All the ovarian follicles ≥ 2 mm were measured, and their relative locations were recorded on an ovarian map in order to follow the sequential development of each individual follicle. Blood samples for P 4 and E 2 determination were collected daily from 1 d before the second injection of PGF 2α (G1) and administration of eCG (G2) until day 10 after ovulation of the cycle. There were significant differences in P 4 and E 2 plasma concentrations between treatments. The CIDR + eCG (500 IU) treatment enhanced the recruitment of smaller follicles and enhanced the maximum diameter and growth rate of large follicles during wave 1.

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Section: Resultsunclassified

Respostas endócrinas e ovarianas associadas com o folículo dominante da primeira onda folicular em ovelhas sincronizadas com CIDR ou PGF2alfa

et al. 2002

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“…At physiological levels, an inverse temporal relationship between serum concentrations of estradiol and FSH in association with the growth of follicular waves has been demonstrated during the breeding season [6,59], but not during anestrus [9,10,60,61]. However, peaks in FSH concentrations and associated follicular waves in sheep have been observed during both the breeding and nonbreeding seasons [1,9,10,[60][61][62]. The studies showing a negative effect of inhibin on FSH secretion have used various preparations such as follicular fluid (crude inhibin) [63] or human recombinant inhibin A [64], or passive immunization against inhibin [23].…”

Section: Discussionmentioning

confidence: 99%

“…Ovarian antral follicular growth occurs in a wave-like pattern in sheep, both during the breeding season [1][2][3][4][5][6][7][8] and seasonal anestrus [9,10]. The emergence of follicular waves is preceded by a transient peak in circulating FSH concentrations [2,3,6,[8][9][10][11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

The Effect of the Manipulation of Follicle-Stimulating Hormone (FSH)-Peak Characteristics on Follicular Wave Dynamics in Sheep: Does an Ovarian-Independent Endogenous Rhythm in FSH Secretion Exist?1

Duggavathi

Bartlewski

Agg

et al. 2005

Biology of Reproduction

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We designed three experiments to investigate the relationship between FSH peaks and ovarian follicular waves and to examine whether an endogenous rhythm of FSH peaks exists in sheep. In experiment 1, anestrous ewes were treated with ovine FSH (oFSH) or vehicle (6 ewes per group) at the expected time of an endogenous FSH peak, to double the FSH-peak amplitude in treated ewes. In experiment 2, anestrous ewes were treated with either oFSH or vehicle (6 ewes per group) at the expected time of two consecutive interpeak nadirs, such that the treated ewes had 5 FSH peaks in the time frame of 3 FSH peaks in control ewes. In experiment 3, to measure FSH concentrations, daily blood samples were collected from 5 cyclic ewes for a control period during the estrous cycle and then for three 17-day periods after ovariectomy. Daily blood samples were collected from another group of 8 ovariectomized ewes that were treated with estradiol-releasing implants and intravaginal progestogen sponges. Doubling the FSH-peak amplitude did not alter the characteristics of the following follicular wave. Increasing the frequency of FSH peaks stimulated the emergence of additional follicular waves, but did not alter the rhythmic occurrence of FSH peaks and follicular wave emergence. Endogenous follicular waves in oFSH-treated ewes emerged and grew in the presence of the growing largest follicle of the induced follicular waves. Finally, based on the observation of serum FSH concentrations in ovariectomized ewes, it appears that there exists an endogenous rhythm for peaks in daily serum FSH concentrations, which is, at least in part, independent of regulation by ovarian follicular growth patterns.

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“…In heifers, variation in the interval from PGF 2α treatment to ovulation was attributed to the wave of origin of the ovulatory follicle (Kastelic and Ginther 1991). A wave-like pattern of follicular dynamics has been documented in sheep (Noel et al 1993;Ginther et al 1995;Souza et al 1996). The objective of the present study was to determine the wave of origin of the POF in ewes when luteolyis was induced by giving PGF 2α 5 or 9 d after ovulation (at the expected time of emergence of wave 2 and the plateau phase of wave 2, respectively (Ginther et al 1995;Rubianes et al 1997)].…”

mentioning

confidence: 93%

Origin of the preovulatory follicle after induced luteolysis during the early luteal phase in ewes

Viñoles¹,

Rubianes²

1998

Can. J. Anim. Sci.

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Origin of the preovulatory follicle after induced luteolysis during the early luteal phase in ewes. Can. J. Anim. Sci. 78: 429-431. The origin of the preovulatory follicle (POF) was determined by daily transrectal ultrasonographic examinations in ewes given PGF 2α on day 5 (n = 8) or day 9 (n = 8) post-ovulation. In all day-9 ewes, the POF originated from wave 2 while in the day-5 group it originated from wave 1 (n = 5) or wave 2 (n = 3). When the POF originated from wave 2 in day-5 ewes, the dominant follicle of wave 1 emerged earlier than in ewes with the POF from wave 1 (day -1.0 vs. day 0.8, P < 0.05) and was regressing at the time of PGF 2α treatment (diameter 4.1 ± 0.4 vs. 2.8 ± 0.3 mm, P < 0.05). The dominant follicle of wave 1 became POF if it was in the growing or plateau phase at the time of luteolysis. If it was already in the regressing phase, the dominant follicle of wave 2 became the POF.Key words: PGF 2α , luteolysis, ovarian follicular waves, ultrasonography, ewes Viñoles, C. et Rubianes, E. 1998. Origine du follicule préovulatoire aprés de la luteolysis induite tôt pendant la phase luteále chez les brebis. Can. J. Anim. Sci. 78: 429-431. L' origine du follicule préovulatoire aprés la luteolysis induite avec PGF 2( au cirequième jour (groupe 5, n = 8) et au neuvième jour (groupe 9, n = 8) post-ovulation a été étudié utilisant de la ultrasonographie transrectal journalierè. Dans toutes les brebis du groupe 9, le follicule préovulatoire a été originé a partir de la deuxième vague tandis que ceux du groupe 5 ont été originés à partir de la première vague en 5 brebis et de la deuxième vague en 3. Chez le groupe 5 avec follicule préovulatoire originé dans la deuxième vague, le follicule dominant de la première vague était rétreci le jour de l' administration de la dose de PGF 2α . En conclusion, aprés le traitement avec PGF 2α pendant les premiers jours de la phase luteal, le follicule dominant de la premierè vague s'est tourné en follicule ovulatoire si la luteolysis a été induite pendant son accroissement ou les phases plateaux. Une luteolysis induite plus tardivement conduira au fait que le follicule ovulatoire prendra son origine à partir de la deuxiemè vague.Mots clés: PGF 2α , luteolysis, vagues folliculaires, ultrasonographie, brebisThe injection of an analogue of PGF 2α between days 5 and 14 of the estrous cycle (estrus = day 0) in ewes reliably induces luteal regression, estrus and ovulation (Acritopoulou and Haresign 1980). However, the interval from treatment to estrus is variable, and is apparently affected by day of PGF 2α treatment. In heifers, variation in the interval from PGF 2α treatment to ovulation was attributed to the wave of origin of the ovulatory follicle (Kastelic and Ginther 1991). A wave-like pattern of follicular dynamics has been documented in sheep (Noel et al. 1993;Ginther et al. 1995;Souza et al. 1996). The objective of the present study was to determine the wave of origin of the POF in ewes when luteolyis was induced by giving PGF 2α 5 or 9 d after ovulation (at the e...

show abstract

Ovarian follicular dynamics in Suffolk ewes at different periods of the year

Cited by 77 publications

References 1 publication

Respostas endócrinas e ovarianas associadas com o folículo dominante da primeira onda folicular em ovelhas sincronizadas com CIDR ou PGF2alfa

Respostas endócrinas e ovarianas associadas com o folículo dominante da primeira onda folicular em ovelhas sincronizadas com CIDR ou PGF2alfa

The Effect of the Manipulation of Follicle-Stimulating Hormone (FSH)-Peak Characteristics on Follicular Wave Dynamics in Sheep: Does an Ovarian-Independent Endogenous Rhythm in FSH Secretion Exist?1

Origin of the preovulatory follicle after induced luteolysis during the early luteal phase in ewes

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