Background: Intrauterine Insemination (IUI)is one of the common first-line assisted reproductive technologies (ART) for couples suffering infertility. Controlled ovarian stimulation (COH) with clomiphene citrate (CC) or aromatase inhibitor (like Letrozole) is often used in adjunct to IUI to increase the pregnancy outcome. Both CC and letrozole can be given alone as a single ovulation induction agent or they can be combined with injectable gonadotropin for purpose of superovulation. Study objectives: To systematically review the efficacy and adverse outcomes of letrozole and CC for supervulation in infertility patients undergoing IUI. Method: Systematic review of pertinent randomised controlled trials (RCT) using the bibliographic databases EMBASE, PubMed, Cochrane, Medline (OVID), Academic Search Premier and CINAHL. References of selected articles identified were hand-searched for additional relevant citations. RCTs that have compared the pharmacological performance of CC and letrozole as a single agent or combination with equal dose of gonadotropins were included. Results: Ten published randomized controlled trials were included in this review. The mean age, infertility diagnosis and duration of infertility of the recruited participants were comparable. Pregnancy rate was found to be comparable in clomiphene citrate (CC) group and letrozole (L) group. Higher peak estrogen concentration and greater number of dominant follicles were reported in CC group. Endometrial thickness was found significantly greater in L group. Adverse outcomes of rate of miscarriage, multiple pregnancies, ectopic pregnancies, OHSS and fetal anomalies were not significantly different between the two intervention groups. Conclusion: Letrozole and CC, considered equally patient-friendly agent due to oral route administration. Both agents achieved similar pregnancy rates without any increased risk of adverse events in either group. Letrozole can be used as alternative first-line OI agent to CC in reproductive treatments. Drug selection for patients should be done according to the cost effectiveness, duration of therapy, characteristics and compliance of patients. / published_or_final_version / Public Health / Master / Master of Public Health

Thesis (DMed (Obstetrics and Gynaecology))--Stellenbosch University, 2008. / Chapter 1 presents a literature study on the diagnostic debate of PCOS. The literature study includes a discussion of the recent Rotterdam consensus statement regarding the diagnosis of PCOS. This is followed by a discussion on the essential work-up of the patient presenting with PCOS. Finally, chapter 1 presents a discussion on the complexity of the different variations in women presenting with PCOS. Chapter 2 is a literature review on ovulation induction methods in patients who present with PCOS. This literature study puts special emphasis on the different available methods used for ovulation induction in women with PCOS and the profounding effect weight loss will have in managing these patients. This chapter also addresses the use of newer agents, like aromatase inhibitors (Letrozole), and the current role of each of these agents in ovulation induction protocols. Chapter 3 is a literature overview on the effect of Metformin in Clomiphene-resistant PCOS women. The inclusion criteria of this review was all prospective randomized trials where Metformin was added for ovulation in the Clomiphene-resistant PCOS patient. The data is presented as a metaanalysis. Chapter 4 is a prospective randomise control trial to evaluate the benefit of metformin if added to Clomiphene in a primary ovulation induction protocol in comparison to Clomiphene alone. This chapter also evaluates all factors influencing ovulation outcome. Finally in the discussion section all the recent studies published addressing this topic were reviewed. Chapter 5 is a literature review to evaluate the classification systems for semen parameters and the in vivo fertility potential. This data is also used to establish fertility/subfertility thresholds for semen parameters. This chapter also presents the results of a prospective and retrospective study of the semen analysis of the partners of women with PCOS. We believe that this population presents the best reference group to study the semen profile of the general male population. Chapter 6 is a summary of the results of these studies and serves as an evidence based approach for ovulation induction in women with PCOS.

published_or_final_version / abstract / Obstetrics and Gynaecology / Doctoral / Doctor of Philosophy

Thesis (Ph. D.)--University of Wisconsin, 1973. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Orientador: Anaglória Pontes / Resumo: O câncer de mama é uma doença maligna relativamente comum em mulheres adultas jovens, justificando a preocupação com a potencial toxicidade gonadal relacionada à quimioterapia. É importante considerar o encaminhamento precoce de pacientes jovens com câncer de mama que tenham desejos reprodutivos para especialistas, a fim de discutir sobre a preservação da fertilidade. A criopreservação de embriões ou de oócitos estão entre os principais métodos à disposição, e para conseguir isso, estimulação ovariana controlada (EOC) é o primeiro passo a ser considerado. O presente estudo tem como objetivo apresentar protocolo de estimulação ovariana em para preservação da fertilidade em pacientes com câncer de mama. De novembro de 2014 a dezembro de 2016, 109 pacientes com câncer de mama com menos de 40 anos de idade foram selecionadas para preservar seu potencial reprodutivo. Elas foram divididas de acordo com a fase do ciclo menstrual em que o estímulo ovariano foi iniciado: fase folicular inicial, fase folicular tardia e fase lútea. Para reduzir o tempo necessário da obtenção dos oócitos, este estudo utilizou o princípio do início aleatório, no qual a EOC pode ser iniciada durante qualquer período do ciclo menstrual sem consequências negativas. O letrozol foi utilizado durante toda a estimulação para diminuir as concentrações de estradiol, independentemente da imunohistoquímica tumoral. Na presença de tumores positivos ao estradiol, e indicação de quimioterapia neoadjuvante, o tamoxi... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Breast cancer is a relatively common malignancy in young adult women, justifying the concern about the potential gonadal toxicity related to chemotherapy. It is important to consider early referral of young breast cancer patients with reproductive desires to fertility specialists, in order to discuss the fertility preservation. Embryos or oocytes cryopreservation are among the main methods available, and to achieve that, controlled ovarian stimulation (COS) is the first step to be considered. From November 2014 to December 2016, 109 breast cancers patients under 40 years were enrolled to preserve their reproductive potential. They were divided according to the menstrual cycle status in: initial follicular phase, late follicular phase and luteal phase. In order to reduce the time necessary to obtain the oocytes, this study used the principle of random start, in which the COS can be initiated during any period of the menstrual cycle without negative consequences. Letrozole was used during all stimulation to reduce estradiol concentrations, regardless of tumor immunohistochemistry. In the presence of estradiol positive tumors, and indication of neoadjuvant chemotherapy, tamoxifen was administerd as an additional protective measure. A GnRH agonist was used to trigger ovulation, in order to mitigate the risk of ovarian hyperstimulation syndrome. The following parameters were analyzed: age, day of COS start, number of days required to COS, total FSH dosage, estradiol levels at fi... (Complete abstract click electronic access below) / Mestre

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Agradecemos a compreensão. on 2017-06-30T12:25:51Z (GMT) / Submitted by FELIPE ANDREOTTA CAVAGNA null (cavfelipe@hotmail.com) on 2017-07-03T18:22:57Z No. of bitstreams: 1 Tese completa com ficha catalográfica.pdf: 2297427 bytes, checksum: 8e382c810380d26d332762e12fa2ab64 (MD5) / Approved for entry into archive by Luiz Galeffi (luizgaleffi@gmail.com) on 2017-07-04T16:36:48Z (GMT) No. of bitstreams: 1 cavagna_fa_me_bot.pdf: 2297427 bytes, checksum: 8e382c810380d26d332762e12fa2ab64 (MD5) / Made available in DSpace on 2017-07-04T16:36:48Z (GMT). No. of bitstreams: 1 cavagna_fa_me_bot.pdf: 2297427 bytes, checksum: 8e382c810380d26d332762e12fa2ab64 (MD5) Previous issue date: 2017-04-07 / O câncer de mama é uma doença maligna relativamente comum em mulheres adultas jovens, justificando a preocupação com a potencial toxicidade gonadal relacionada à quimioterapia. É importante considerar o encaminhamento precoce de pacientes jovens com câncer de mama que tenham desejos reprodutivos para especialistas, a fim de discutir sobre a preservação da fertilidade. A criopreservação de embriões ou de oócitos estão entre os principais métodos à disposição, e para conseguir isso, estimulação ovariana controlada (EOC) é o primeiro passo a ser considerado. O presente estudo tem como objetivo apresentar protocolo de estimulação ovariana em para preservação da fertilidade em pacientes com câncer de mama. De novembro de 2014 a dezembro de 2016, 109 pacientes com câncer de mama com menos de 40 anos de idade foram selecionadas para preservar seu potencial reprodutivo. Elas foram divididas de acordo com a fase do ciclo menstrual em que o estímulo ovariano foi iniciado: fase folicular inicial, fase folicular tardia e fase lútea. Para reduzir o tempo necessário da obtenção dos oócitos, este estudo utilizou o princípio do início aleatório, no qual a EOC pode ser iniciada durante qualquer período do ciclo menstrual sem consequências negativas. O letrozol foi utilizado durante toda a estimulação para diminuir as concentrações de estradiol, independentemente da imunohistoquímica tumoral. Na presença de tumores positivos ao estradiol, e indicação de quimioterapia neoadjuvante, o tamoxifeno foi utilizado como uma medida de proteção adicional. Um agonista do GnRH foi utilizado para desencadear a maturação folicular final, diminuindo o risco de síndrome de hiperestimulação ovariana. Foram analisados os seguintes parâmetros: idade das pacientes, dia de início da EOC, número de dias de EOC, dose total de FSH, níveis de estradiol no dia de maturação folicular final, número de oócitos coletados e número de oócitos vitrificados. A idade média dos pacientes foi de 31,27 ± 4,22 anos. A duração média da EOC foi de 10,0 ± 1,39 dias. O número médio de oócitos coletados foi de 11,62 ± 7,96 e o número médio de oócitos vitrificados foi de 9,60 ± 6,87. A concentração média de estradiol no dia do desencadeamento da ovulação foi de 706,30 ± 450,48 pg / mL, e a dose média de FSH administrada foi 2610,00 ± 716,51 UI. Ao comparar os resultados de acordo com a fase do ciclo no qual a EOC foi iniciada, não houve diferenças significativas no número de oócitos colhidos e vitrificados, duração da estimulação ovariana e dos níveis de estradiol no dia do desencadeamento da ovulação. Observou-se uma diminuição estatisticamente significativa da dose total de FSH administrada nos grupos que iniciaram a EOC na fase folicular tardia e na fase lútea, quando comparada com a fase folicular inicial. Esses resultados sugerem que a criopreservação de oócitos ou embriões com um protocolo específico para pacientes com câncer de mama, é eficaz e pode ser oferecida a mulheres jovens submetidas a tratamento citotóxico que têm preocupações relacionadas ao seu futuro reprodutivo. / Breast cancer is a relatively common malignancy in young adult women, justifying the concern about the potential gonadal toxicity related to chemotherapy. It is important to consider early referral of young breast cancer patients with reproductive desires to fertility specialists, in order to discuss the fertility preservation. Embryos or oocytes cryopreservation are among the main methods available, and to achieve that, controlled ovarian stimulation (COS) is the first step to be considered. From November 2014 to December 2016, 109 breast cancers patients under 40 years were enrolled to preserve their reproductive potential. They were divided according to the menstrual cycle status in: initial follicular phase, late follicular phase and luteal phase. In order to reduce the time necessary to obtain the oocytes, this study used the principle of random start, in which the COS can be initiated during any period of the menstrual cycle without negative consequences. Letrozole was used during all stimulation to reduce estradiol concentrations, regardless of tumor immunohistochemistry. In the presence of estradiol positive tumors, and indication of neoadjuvant chemotherapy, tamoxifen was administerd as an additional protective measure. A GnRH agonist was used to trigger ovulation, in order to mitigate the risk of ovarian hyperstimulation syndrome. The following parameters were analyzed: age, day of COS start, number of days required to COS, total FSH dosage, estradiol levels at final follicular maturation day, number of collected oocytes and number of vitrified oocytes. The mean age of patients was 31.27±4.22 years. The average duration of COS was 10.0±1.39 days. The mean number of collected oocytes was 11.62±7.96 and the mean number of vitrified oocytes was 9.60±6.87. The mean estradiol concentration on the day of the trigger was 706.30±450.48 pg/mL, and the mean dose of FSH administered was 2610.00±716.51 IU. When comparing the outcomes according to the phase of the cycle in which COS was commenced, there were no significant differences in the number of oocytes collected and vitrified, ovarian stimulation length and estradiol levels on the day of the trigger. It was observed a statistically decrease of the total FSH dose administered in the groups starting COS in the late follicular phase and in the luteal phase, when compared to the initial follicular phase These results suggest that oocyte or embryos cryopreservation with a specific protocol for breast cancer patients, is effective, safe, and may be offered to young women undergoing cytotoxic treatment who have concerns related to their reproductive future.

Clomiphene citrate (CC) is the leading treatment for women with anovulatory infertility. The precise mechanism of action of the drug on the hypothalamic-pituitary-gonadal (HPG) axis has yet to be determined. Neurons expressing kisspeptin, neurokinin B (NKB) and dynorphin A (Dyn), collectively called KNDy neurons, in the arcuate nucleus (ARC) of the hypothalamus have been shown to play an integral role in the estradiol (E2) feedback pathways of the reproductive system in mammals. KNDy neurons are found in the ARC and the anteroventral periventricular nucleus (AVPV) in humans but have been predominantly reported to not express NKB and Dyn in rodents. The axons of these neurons project to the medial eminence (ME) in the region where the gonadotropin-releasing hormone (GnRH) terminals and fibres are located. It was hypothesised that CC upregulates the gene expression of kisspeptin and neurokinin B while down-regulating the gene expression of dynorphin A which results in a leutenizing hormone surge and an increase in oestradiol which causes ovulation. This was a randomized experiment which included 18 female Sprague-Dawley rats in which the aim was to analyse the expression of kisspeptin, NKB and Dyn in the ARC and the AVPV as well as blood plasma levels of oestradiol and leutinizing hormone (LH) in female rats after CC administration. Six of the rats constituted the control group that received a vehicle solution. The second group of 6 rats received the intervention in the form of CC and the third group of six rats received CC as well as p234-penetratin, a kisspeptin antagonist (KpA). The mRNA expression of the KNDy genes were analysed using real-time quantitative polymerase chain reaction (qPCR) and the plasma levels of E2 and LH were analysed by enzyme-linked immunosorbant assays (ELISA). ELISA results show that the E2 concentration in the group that received CC plus KpA was found to be marginally lower than that of the control group but there was no significant difference between the E2 concentrations of the control group and the group that received only CC. The LH concentration in the group that received CC plus KpA was significantly higher than both other groups but again, there was no significant difference between the LH concentration control group and the group that only received CC. The qPCR showed that in the AVPV, the kisspeptin expression of the CC group and the CC plus KpA groups are marginally higher than that of the control group. Conversely, the Dyn expression of the CC group and the CC plus KpA groups are marginally lower than that of the control group in the AVPV. There were no significant differences in NKB expression across the three groups. In the ARC, there were no significant differences in kisspeptin or Dyn expression across the groups. The NKB expression of the CC group was marginally lower than that of the control and there was no significant difference between the CC plus KpA group and the control group. In summary, CC appears to have a marginal effect on the kisspeptin and Dyn mRNA via the positive feedback systems in the rat AVPV as well as a significant decrease of NKB mRNA via the negative feedback systems in the ARC. To increase the validity of similar future studies, higher sample sizes, different drug administration doses, possibly more precise surgical techniques and more accurate age determination methods or ovariectomised rats could be used. / Dissertation (MSc)--University of Pretoria, 2016. / Physiology / MSc / Unrestricted

published_or_final_version / Obstetrics and Gynaecology / Doctoral / Doctor of Philosophy

The study evaluated strategies for induction of ovulation for fixed-time AI (FTAI) in lactating dairy cows submitted to Ovsynch-type protocols initiated after a novel presynchronization strategy. A total of 909 lactating dairy cows from 6 dairy herds were at 36.7 ± 0.28 d in milk, with body condition score of 3.16 ± 0.02 when they underwent presynchronization. On D-15, all cows received an intravaginal progesterone (P4) implant of 1.0 g P4 (new or used) or a used device of 2.0 g P4 and 7 d later (D-8) the P4 implant was removed and cows received 1.0 mg i.m. estradiol cypionate (EC) and 0.530 mg i.m. sodium cloprostenol (PGF). On D0, a synchronization of ovulation protocol for FTAI was initiated and cows were randomly assigned to 1 of 3 experimental groups, that differed only on the strategy to induce ovulation at the end of the protocol. The protocols initiated on D0 with 16.8 μg i.m. of buserelin acetate (GnRH) concomitant with insertion of a 2.0 g (new or used) P4 device. On D6, every cow received 0.530 mg PGF followed by a second PGF on D7, concomitant with P4 device withdrawal. In Group EC, cows received 1.0 mg EC on D7 (time of P4 device withdrawal) as inducer of ovulation. In Group EC/G, cows received EC on D7 and 8.4 μg GnRH administered 16 h before FTAI (56 h after the first PGF). Finally, in Group G, cows only received 8.4 μg GnRH at 56 h after the first PGF. The FTAI was performed on D9 (48 h after P4 device withdrawal) in all experimental treatments and pregnancy diagnosis was performed 31 and 60 d after FTAI. The pregnancy per AI (P/AI) was not different between cows with or without CL on D-15 (44.7 vs. 38.7%) and on D0 (44.3 vs. 37.3), however, cows with CL on D6 had higher P/AI than cows without CL at PGF (45.9 vs. 17.7%). Estrus expression was greater in cows receiving EC compared to cows receiving only GnRH (80.0 vs. 46.1%). Moreover, cows expressing estrus had greater P/AI than cows not showing estrus on d31 (50.8 vs. 34.8) and on d60 (48.5 vs. 27.6%), however, estrus did not affect pregnancy loss. There were no differences between experimental treatments on P/AI on d30 with an overall P/AI of 40.4% (367/909). Pregnancy loss and P/AI on d60 did not differ between treatments. In conclusion, the reproductive program has potential to promote high fertility and the 3 strategies to induce the final synchronized ovulation produced similar fertility. Further research is needed to optimize the presynchronization strategy and to more definitively determine the effect of different methods of ovulation induction on P/AI and in particular on the pregnancy loss after the d30 pregnancy diagnosis. / O estudo avaliou estratégias para induzir a ovulação final em protocolos de IA em tempo fixo (IATF) em vacas leiteiras submetidas a protocolos do tipo Ovsynch iniciados após uma pré-sincronização. Um total de 909 vacas em lactação de seis diferentes fazendas estava com 36,7 ± 0,28 d em lactação e escore de condição corporal de 3,16 ± 0.02 quando iniciaram o protocolo de pré-sincronização. No D-15 todas as vacas receberam um implante de progesterona (P4) de 1,0 g (novo ou usado) ou de 2,0 g (usado), e 7 d após (D-8), o implante de P4 foi retirado e as vacas receberam 1,0 mg i.m. de cipionato de estradiol (CE) e 0,530 mg de cloprostenol sódico (PGF). No D0, iniciou-se o protocolo de sincronização da ovulação para a IATF a as vacas foram aleatoriamente distribuídas em 1 de 3 grupos experimentais, que diferiam somente na estratégia de indução da ovulação ao final do protocolo. Os protocolos se iniciaram no D0 com 16,8 μg de acetato de buserelina (GnRH) concomitante com a inserção de um dispositivo de P4 de 2,0 g (novo ou usado). No D6, todas as vacas receberam 0,530 mg de PGF seguida de uma segunda PGF no D7, concomitante com a retirada do implante de P4. No Grupo CE, as vacas receberam 1,0 mg de CE no D7 (momento da retirada do dispositivo de P4) como indutor de ovulação. No Grupo CE/G, as vacas receberam 1,0 mg de CE no D7 e 8,4 μg de GnRH 16 h antes da IATF (56 h após a primeira PGF). Por último, no Grupo G, as vacas receberam somente 8,4 μg de GnRH no mesmo momento do grupo CE/G. A IATF foi realizada no D9 (48 h após a retirada do implante de P4) em todos os grupos e o diagnóstico de gestação ocorreu 31 e 60 d após a IATF. A prenhez por IA (P/IA) não diferiu entre vacas com ou sem CL no D-15 (44.7 vs. 38.7%) e no D0 (44.3 vs. 37.3), no entanto, vacas com CL no D6 apresentaram maior P/IA do que vacas sem CL na PGF (45.9 vs. 17.7%). Expressão de cio foi maior em vacas que receberam CE do que vacas que receberam somente GnRH (80.0 vs. 46.1%). Além disso, vacas que expressaram cio tiveram maio P/IA no d31 (50.8 vs. 34.8) e no d60 (48.5 vs. 27.6%), no entanto, expressão de cio não afetou perda gestacional. Não houve diferença entre os tratamentos experimentais na P/IA no d31, e a P/IA média foi 40.4% (367/909). Perda gestacional e P/IA aos 60 d não diferiram entres os grupos. Concluímos que o programa reprodutivo tem potencial para promover alta fertilidade e que as 3 estratégias para induzir a ovulação final do programa reprodutivo promoveram fertilidade similares. No entanto, é necessário que seja melhor estudado a interação entre expressão de cio e tratamentos nos parâmetros de fertilidade, assim como, estudar mais a fundo os efeitos dos tratamentos (indutores de ovulação) na fertilidade após o d30 e na perda gestacional.

Submitted by (lucia.rodrigues@ufrpe.br) on 2017-02-07T16:28:31Z No. of bitstreams: 1 Antonio Matos Fraga Junior.pdf: 1236085 bytes, checksum: 13e7f8734f0795648537ab792eac5d87 (MD5) / Made available in DSpace on 2017-02-07T16:28:31Z (GMT). No. of bitstreams: 1 Antonio Matos Fraga Junior.pdf: 1236085 bytes, checksum: 13e7f8734f0795648537ab792eac5d87 (MD5) Previous issue date: 2011-02-08 / This study aimed to assess the follicular dynamics of Guzerat cows treated with three protocols for synchronization of ovulation where they used vaginal implant impregnated with progesterone or the Ovsynch protocol, besides the use of estradiol benzoate or GnRH to induce ovulation.There were used 18 PO Guzerat cows, multiparous non-lactating, aging between four and seven years, good body score condition, ranging from 3.0 to 4.0, The animals were kept in extensive management, where the diet provided met the nutritional requirements including protein mineral salt and water "ad libitum". The animals were divided into three groups, in group 1 (n = 6) it was applied at the D0, an intravaginal device CIDR® along with 2 mg of estradiol benzoate, at D8 it was administered 300 mg of a prostaglandin analogue and 300 IU of eCG besides intravaginal device removal, at D9 it was administered 1 mg of estradiol benzoate and at D11 artificial insemination was carried out. In group 2 (n = 6) it was used the same protocols as in group 1 except for the induction of ovulation when it was used 17 mg of a GnRH analogue and at D11 artificial insemination was carried. In group 3 (n = 6) was applied at D0, 200 mg of GnRH analogue, 0.530 mg of prostaglandin analogue at D7, at D9 it was administered 100 mg of GnRH analogue and at D10 artificial insemination was carried. From D0 to D8 animals were examined daily (24/24 h) by transrectal ultrasound .After removal of the implant on D8 in groups 1 and 2 and application of prostaglandin D7 (group 3) animals were assessed four times a day (6/6 hours) until D10 of the Protocol. A new follicular wave emergence for groups 1, 2 and 3 was observed respectively, 2.6 ± 0.16; 2.7 ± 0.18 and 2.9 ± 0.16 days, with no statistical difference (P < 0.05) between groups .There was statistical difference for groups 1, 2 and 3 in the range of wave emergence and ovulation in days, 7.1  0.18; 6.37 0.31; 5.33 0.66, the interval between implant removal and ovulation in hours, 64.2 6.99, 61.0 12.36, interval between the application of inducing ovulation and in hours, 43.6 6.89, 41.0 11.25, 38.2 7.89, greatest diameter of the DF (day 8), 10.71 0.30, 9.41 0.24, 9.75 0.35, greatest diameter of the DF (day 10), 13.1 0.23, 11.7 0.22, 12.0 0.34, Average follicle growth until day 8 - (mm / day), 1.36 0.07, 0.92 0.10, 1.10 0.11, Average follicle growth of 8-10 days - (mm / day), 2.40 0.08, 2.28 0.11, 2.23 0.10 and the percentage of animals that ovulated, 83.34% (5/6) , 66.67% (4/6), 50% (3/6). So the protocols of experimental groups 1 and 2 were moreeffective in promoting the synchronization of ovulation and are indicated to be used in a program of fixed-time artificial insemination in Guzerat cows. / Este trabalho teve por objetivo avaliar a dinâmica folicular de vacas da raça Guzerá tratadas com três protocolos para sincronização da ovulação onde se utilizaram implantes vaginais impregnados com progesterona ou o protocolo Ovsynch, além da utilização de benzoato de estradiol ou GnRH como indutor da ovulação. Foram utilizadas 18 vacas PO da raça Guzerá, multíparas, não-lactantes, com idades entre quatro e sete anos, escore de condição corporal de 3,0 a 4,0 (escala de 1 a 5). Os animais foram mantidos em regime extensivo, onde a dieta fornecida supriu as exigências nutricionais, receberam sal mineral proteinado e água “ad libitum”. Os animais foram divididos em três grupos, No grupo 1 (n=6) foi aplicado no D0, mesmo dia do dispositivo intravaginal CIRD®, 2 mg de benzoato de estradiol, no dia oito (D8), foram aplicados 0,530 mg de análogo de prostaglandina, 300 UI de eCG e foi retirado o dispositivo intravaginal, no dia nove (D9) foi aplicado 1 mg de benzoato de estradiol. No grupo 2 (n=6) foi aplicado no D0, mesmo dia do dispositivo intravaginal CIRD®, 2 mg de benzoato de estradiol, no dia oito (D8), foram aplicados 0,530 mg de análogo de prostaglandina, 300 UI de eCG IM e foi retirado o dispositivo intravaginal, no dia nove (D9) foi aplicado 17 μg de um análogo do GnRH. No grupo 3 (n=6) foi aplicado no D0, 200 μg de análogo do GnRH, 0,530 mg de análogo da prostaglandina no dia sete (D7) no dia nove (D9) foi aplicado 100 μg de análogo do GnRH. A partir do dia zero até o dia 8 os animais foram examinados diariamente (24/24 h) por via trans-retal com auxílio de ultrassom. Após a retirada do implante no dia 8 (grupos 1 e 2) e aplicação da prostaglandina no dia 7 (grupo 3) os animais foram avaliados 4 vezes por dia (6/6 horas) até o dia 10 do protocolo. Uma nova emergência da onda folicular para os grupos 1, 2 e 3 ocorreu respectivamente, em 2,6 ± 0,16; 2,7 ± 0,18 e 2,9 ± 0,16 dias, não havendo diferença estatística (P <0,05) entre os grupos (Tabela 1). Houve diferença estatística para os grupos 1, 2 e 3 no intervalo entre emergência da onda e ovulação em dias, 7,1  0.18; 6,37 0,31; 5,33 0,66; intervalo entre a retirada do implante e a ovulação em horas, 64,2 6,99; 61,0 12,36; intervalo entre a aplicação do indutor e a ovulação em horas, 43,6 6,89; 41,0 11,25; 38,2 7,89, maior diâmetro do FD (dia 8), 10,71 0,30; 9,41 0.24; 9,75 0,35, maior diâmetro do FD (dia 10), 13,1 0,23; 11,7 0,22; 12,0 0,34; Média de crescimento do folículo até dia 8 – (mm/dia), 1,36 0,07; 0,92 0,10; 1,10 0,11; Média de crescimento do folículo do dia 8-10 – (mm/dia), 2,40 0,08; 2,28 0,11; 2,23 0,10 e na porcentagem de animais que ovularam, 83,34% (5/6), 66,67% (4/6), 50% (3/6). Portanto os protocolos dos grupos experimentais 1 e 2 se mostraram mais eficientes em promover a sincronização da ovulação e são indicados para utilização em programa de inseminação artificial em tempo fixo em vacas da raça Guzerá.