Effects of estradiol and progestins on follicular regression before, during, and after follicular deviation in postpartum beef cows

Siqueira, Lucas Carvalho; Oliveira, João Francisco Coelho de; Rovani, Monique Tomazele; Ferreira, Rogério; Borges, Luiz Felipe Kruel; Gonçalves, P. B. D.

doi:10.1016/j.theriogenology.2008.09.024

Cited by 10 publications

(8 citation statements)

References 23 publications

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“…In Nelore cows, however, Sales et al (2012) found an average DF diameter of 13.4±0.4 mm at FTAI when ovulation was induced by EB. Siqueira et al (2009) found similar data in Bos taurus beef cows, which had follicular diameters of 10.5±0.1, 10.7±0.1 and 10.6±0.4 mm when synchronized with intravaginal devices containing 250 mg of medroxyprogesterone acetate, devices containing 250 mg of medroxyprogesterone acetate plus 100 mg of P4 given im, or 1 g of P4, respectively.…”

Section: Discussionsupporting

confidence: 70%

“…The intravaginal device contains natural P4 that exerts negative feedback on estradiol and inhibits the LH surge during the treatment period (5-10 days), thereby preventing estrus and ovulation of the dominant follicle (DF); (STOCK;FORTUNE, 1993;SAVIO et al, 1993). When associated with estrogen, P4 promotes regression of the DF and the synchronized emergence of a new follicular wave (BARUSELLI et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

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Ovarian follicular dynamics of Nelore (Bos indicus) cows subjected to a fixed-time artificial insemination protocol with injectable progesterone

et al. 2013

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This study aims to evaluate ovarian follicular dynamics of Nelore cows subjected to fixed-time artificial insemination (FTAI) with injectable progesterone (P4) or intravaginal device. In the device group, 20 cows received an intravaginal device with 1 g P4 and administration of 2 mg estradiol benzoate (EB) intramuscularly (im) on D0. The device was removed on D8, followed by administration of 500 μg cloprostenol, 300 IU equine chorionic gonadotropin (eCG) and 1 mg estradiol cypionate (EC), im. The cows were inseminated 48h later. In the injectable group, 350 mg P4 (300 mg subcutaneously and 50 mg im) and 2 mg EB im were administered on D0 to 16 cows. On D6, 500 μg cloprostenol, 300 IU eCG and 1 mg EC were administered im. The FTAI was performed 48h later. Sixty-five percent of cows from the device group (13/20) and 75% from the injectable group (12/16) showed follicles ≥ 5 mm on D4 (p>0.05). The average rate of follicular growth was 0.92±0.25 mm/day for the device group and 1.06±0.45 mm/day for the injectable group (p>0.05). The average diameter of the dominant follicle (DF) at FTAI was 11.4±1.4 mm for the device group and 10.8±1.8 mm for the injectable group (p>0.05). In the device group, ovulatory follicles (OF) had an average diameter of 12.1±1.4 mm, and in the injectable group 12.3±1.6 mm (p>0.05). Ninety percent of the device group (18/20) and 37.5% of the injectable group (6/16) demonstrated ovulation (p<0.05). The average diameter of the corpus luteum (CL) was 18.7±4.3 mm for the device group and 17.7±3.6 mm for the injectable group. The injectable P4 showed similarity in the presence of follicles ≥ 5 mm on D4, follicular growth rate, diameters of the DF, OF and CL. However, the ovulation rate was higher in the device group. Key words: Bos indicus, ultrasonography, follicular growth, ovulation, dominant follicle ResumoO objetivo deste estudo foi avaliar a dinâmica folicular ovariana de vacas Nelore submetidas à inseminação artificial em tempo fixo (IATF) com progesterona injetável (P4) ou dispositivo intravaginal. No grupo dispositivo, 20 vacas receberam um dispositivo intravaginal com 1 g P4 e 2 mg benzoato de estradiol (BE) por via intramuscular (im) no D0. No D8 o dispositivo foi removido e 500 µg cloprostenol, 300 UI gonadotrofina coriônica equina (eCG) e 1 mg cipionato de estradiol (CE) foram aplicados, im. subcutânea e 50 mg, im) e 2 mg BE im no D0. No D6, 500 μg cloprostenol, 300 UI eCG e 1 mg CE foram administradas im. A IATF foi realizada 48h após o CE. No grupo dispositivo, 65% (13/20) e no grupo injetável 75% (12/16) das vacas apresentaram folículos ≥ 5 mm no D4 (p>0,05). A taxa média de crescimento folicular foi de 0,92±0,25 mm/dia para o grupo dispositivo e 1,06±0,45 mm/dia para o grupo injetável (p>0,05). O diâmetro médio do folículo dominante na IATF foi 11,4±1,4 mm para o grupo dispositivo e 10,8±1,8 mm para o injetável (p>0,05). O diâmetro médio do folículo ovulatório foi 12,1±1,4 mm no grupo dispositivo e 12,3±1,6 mm no grupo injetável (p>0,05). A ovulação ocorreu em 90% (18/20) ...

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Section: Discussionsupporting

confidence: 70%

Section: Introductionmentioning

confidence: 99%

Ovarian follicular dynamics of Nelore (Bos indicus) cows subjected to a fixed-time artificial insemination protocol with injectable progesterone

et al. 2013

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“…Buffalo are sensitive to exogenous estradiol as there is decrease in milk production but the use of E-17 (@1.5 mg) has no effect on milk production (Honparkhe 2010). The smaller doses of E-17 (1.5 mg) used in the present study was found equally effective to the larger doses (2.5 mg, 5 mg and 10 mg) used in cattle to suppress the dominant follicle (Siqueira et al 2009 andHonparkhe et al 2010).…”

supporting

confidence: 44%

Follicular wave emergence and fertility following estrogen based synchronization regimen in anestrus buffaloes (Bubalus bubalis)

Bhat

Dhaliwal

Ghuman

et al. 2021

Indian J of Anim Sci

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The study was undertaken to study the follicular changes around the time of new wave emergence following estradiol-17ï¢ (E-17) + controlled internal drug release (CIDR) based synchronization in 30 anestrus buffaloes. The animals were divided in two Groups, viz. Group I and II. In Group I (n=20), on day 0 (beginning of experiment), buffaloes were administered CIDR device (1.38 g P4) and concurrently received 1.5 mg estradiol-17ï¢ in 1.5 ml canola oil (i. m.). On day 9, CIDR was removed and a prostaglandin (PG) 2 analogue (500 μg, i. m.) was administered. On day 11, buffaloes were administered gonadotropin releasing hormone (GnRH) analogue (20 μg, i.m.) and inseminated twice at 12 h and 24 h following GnRH injection. Group II (control, n=10) received the CIDR-based protocol except the administration of estradiol at the time of CIDR insert. Ovaries were examined for follicular wave emergence, ovulation of dominant follicles at estrus and subsequent conception at 45 days of insemination. The mean diameter of largest follicle was reduced from 8 mm (0th day) to 4 mm on the day of wave emergence (WE), i.e. day 4 in Group I but day 6 in control. The mean number of 4-5 mm follicle was 5.7 in Group I and 4.8 in control on the days of WE. Ovulation and conception rates achieved were 85 vs 60% and 47 vs 30% respectively. In conclusion the new wave emergence was induced earlier by estradiol-17ï¢ administered along with CIDR which ultimately resulted in more ovulation and conception rate in buffalo. Estrogen based protocols might be adopted to improve fertility in anestrum buffaloes.

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“…Progesterone and estradiol have also been used to synchronize follicular waves in cattle since they can induce the regression of most antral follicles present in the ovary at the time of treatment (Siqueira et al, 2009). Intravaginal progesterone devices are inserted along with i.m.…”

Section: Induction Of a New Follicular Wave And Ovulationmentioning

confidence: 99%

Methods to study ovarian function in monovulatory species using the cow as a model

Rovani¹,

Gasperin

Ferreira³

et al. 2017

Anim Reprod

Self Cite

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In this review, we discuss the utility of the cow as an in vivo model to study the regulation of ovarian functions in monovular species. It is increasingly becoming clear that besides endocrine control, locally produced factors play pivotal roles during dominant follicle selection, oocyte maturation, ovulation and luteolysis. Although in vitro culture systems have been used to study these processes, definitive understanding the interactions between endocrine and local factors requires appropriate in vivo models. Most of the experimental approaches to study ovarian functions in vivo in large animals are based on the use of ultrasonography and considerable progress in this field has been made during the last thirty years. It has been shown that cows are an excellent model to collect samples (e.g., follicular fluid, granulosa cells, oocytes) from live animals at specific stages of follicular development in order to study mechanisms of intrafollicular factors in a physiological endocrine environment. In addition to support fundamental studies, the cow model has contributed immensely to the refinement of assisted reproductive technologies, which are now widely used not only in farm animals but also in humans.

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Effects of estradiol and progestins on follicular regression before, during, and after follicular deviation in postpartum beef cows

Cited by 10 publications

References 23 publications

Ovarian follicular dynamics of Nelore (Bos indicus) cows subjected to a fixed-time artificial insemination protocol with injectable progesterone

Ovarian follicular dynamics of Nelore (Bos indicus) cows subjected to a fixed-time artificial insemination protocol with injectable progesterone

Follicular wave emergence and fertility following estrogen based synchronization regimen in anestrus buffaloes (Bubalus bubalis)

Methods to study ovarian function in monovulatory species using the cow as a model

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