The effects of exogenous gonadotropins on oocyte and embryo quality in cattle

Greve, T.; Callesen, Henrik; Hyttel, Poul; Høier, R.; Assey, R. J.

doi:10.1016/0093-691x(94)00013-k

Cited by 97 publications

(42 citation statements)

References 64 publications

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“…The relationship between the number of follicles 2-4 mm in diameter and the oestradiol levels from 12 h before to 36 h after oestrus detection also confirms that the administration of high doses of exogenous gonadotrophins induces the growth of these follicles until the preovulatory stages. Thereafter, the relationship found between the oestradiol levels around estrus and the number of corpora lutea and total and viable embryos confirmed the results already published for cattle [20][21][22], indicating that oestradiol concentration around the onset of oestrus behavior can be considered as an indicator of the population of healthy preovulatory follicles, as in cattle [8].…”

Section: Discussionsupporting

confidence: 76%

“…These effects would be exerted not only straight on the developmental competence of the embryo, but also through a negative influence on the oviduct/uterine environment. In this way, superovulatory treatments cause alterations of the normal reproductive physiology of the donor animal, deviating endocrine patterns from the normal [8]. Some hormones like progesterone and oestradiol have a key role in the maturation of the oviduct and uterine epithelium [9,10].…”

Section: Introductionmentioning

confidence: 99%

“…The influence of follicular and endocrine patterns have been explored for many years in cattle, for a review see Greve et al [8], but to a lesser extent in ewes. The current paper reports results from two experiments designed to discern the role of these factors on the quality of sheep embryos.…”

Section: Introductionmentioning

confidence: 99%

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Influence of maternal environment on the number of transferable embryos obtained in response to superovulatory FSH treatments in ewes

González-Bulnes¹,

García-García²,

Castellanos

et al. 2003

Reprod. Nutr. Dev.

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-In a first experiment, embryo viability was estimated after recovery in the uterus or the oviduct of 70 Manchega ewes following a treatment of superovulation with decreasing doses of OVAGEN TM . Fewer viable embryos (5.6 ± 0.9 vs. 8.3 ± 0.8, P < 0.05) and more degenerative embryos (31.3% vs. 6.8%, P < 0.005) were obtained from the uterus than from the oviduct respectively. In a second experiment performed on 14 ewes, embryo viability was analyzed in relation to the follicular population estimated by ultrasonography (follicles ≥ 2 mm) at the first FSH administration. Progesterone (P4) and oestradiol 17β (E2) concentrations were also determined from the beginning of the superovulation treatment to the recovery of the embryos. The number of viable embryos (4.3 ± 1.4) was positively correlated (r = 0.824) with of 2-4 mm diameter follicles (P < 0.05), and with E2 concentrations at -12 h (r = 0.891, P < 0.01) , 0 h (r = 0.943, P < 0.0001) and +24 h (r = 0.948, P < 0.05) from estrus detection. Prolonged high levels of E2 up to 72 h with low levels of P4 on days 3 and 4 after estrus had a negative (P < 0.05) effect on embryo viability. These results indicate that ovarian response to superovulatory protocols is related to the individual variations in the number of follicles of 2-4 mm at the start of FSH treatment, and that embryo viability is conditioned by the steroid patterns during the time spent in the genital tract of the super-ovulated ewes.embryo viability / ewe / follicular status / super-ovulation / steroid Reprod. Nutr. Dev. 43 (2003) 17-28 17

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Section: Discussionsupporting

confidence: 76%

Section: Introductionmentioning

confidence: 99%

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Influence of maternal environment on the number of transferable embryos obtained in response to superovulatory FSH treatments in ewes

González-Bulnes¹,

García-García²,

Castellanos

et al. 2003

Reprod. Nutr. Dev.

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“…Greve et al (1995) sugeriram que a superestimulação ovariana com FSH prejudica a competência do oócito por alterar a duração da fase folicular. Postula-se que a estimulação hormonal possa desacoplar a maturação do folículo e do oócito (Blondin et al, 1996) e causar uma assincronia entre a maturação nuclear e citoplasmática dos oócitos (Bousquet et al, 1995), levando a um distúrbio no desenvolvimento oocitário.…”

Section: Resultsunclassified

Protocolos de produção in vitro de embriões na raça Gir

Ramos

Ferreira

Sá

et al. 2006

Arq. Bras. Med. Vet. Zootec.

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RESUMOAvaliaram-se os efeitos de dois protocolos de punção folicular na quantidade/qualidade dos oócitos e na produção in vitro de embriões, em vacas da raça Gir, não-lactantes. O ciclo estral foi sincronizado com cloprostenol e ao longo do experimento os animais receberam implantes auriculares de norgestomet, renovados a cada 14 dias. Os animais foram submetidos aos protocolos I (sem estimulação hormonal, com punção folicular duas vezes/semana) e II (pré-tratamento com 250 UI de FSH em doses decrescentes, três dias antes da punção folicular). Os oócitos recuperados foram levados ao laboratório em meio TALP-Hepes e submetidos à maturação. Na fecundação in vitro utilizou-se sêmen de touro Gir, previamente capacitado. Após 22 horas de fecundação, os prováveis zigotos foram co-cultivados com células da granulosa em CR2aa acrescido de 10% de soro fetal bovino. A taxa de clivagem foi avaliada 72 horas pós-fecundação e a de blastocisto 192 horas pós-fecundação. O número total de folículos foi maior (P<0,05) no protocolo II, assim como o número de folículos grandes e médios (P<0,05) e o diâmetro do maior folículo (P<0,05), sendo o número de folículos pequenos (P<0,05) menor. O total de oócitos recuperados por sessão não foi diferente entre os protocolos I e II (P>0,05). O número de oócitos de grau I e a taxa de clivagem foram maiores (P<0,05) e o número de degenerados menor protocolo II. A pré-estimulação ovariana com FSH pode melhorar a qualidade e a taxa de clivagem dos oócitos recuperados por punção folicular em animais Gir.Palavras-chave: bovino, Gir, embrião in vitro, punção folicular, FSH ABSTRACT The effect of two ovum pick-up protocols on amount/quality of oocytes retrived and on in vitro embryo production of Gyr cows was evaluated in non-lactating cycling cows with good body and reproductive conditions. Estrous cycles were synchronized with cloprostenol. During the experiment, animals received norgestomet ear implants, replaced every 14 days. Animals were submitted to protocol I (without hormonal estimulation) and protocol II (pre-stimulation with 250 IU of FSH three days before aspiration). Recovered oocytes were transported in Talp-

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“…It has been reported that approximately 25 to 50% of cows display low embryo responses (Greve et al, 1995) when superstimulation is initiated between these days of the oestrous cycle, most likely due to inadequate or less than optimal follicular condition in a significant proportion of the cows. Indeed, on the day of the initiation of superstimulation, the presence of a dominant follicle decreases the superstimulatory response (Guilbault et al, 1991;Wehrman et al, 1996) while that of a high number of recruitable follicles is associated with significant increases of these responses (Romero et al, 1991;Bungartz and Niemann, 1994).…”

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confidence: 99%

Superovulation following follicular synchronization with GnRH at random stages of the oestrous cycle in heifers

Kohram¹,

Vahedi²,

Nasrollahi³

et al. 2011

CZECH J ANIM SCI

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ABSTRACT:The objective of this study was to develop a superovulatory program based on synchronization of follicular waves with GnRH which could be applied regardless of the stage of the oestrous cycle. 36 heifers were subjected to this experiment and GnRH (Cystorelin, 200 µg) was applied between Days 0 and 7 (n = 15), 8 and 12 (n = 8) or 13 and 20 (n = 13) of the oestrous cycle. Four days after GnRH treatment, all follicles ≥ 6 mm of heifers (n) were either punctured (n = 21) or left intact (n = 15). All heifers were superstimulated from Day 6 to Day 10 after GnRH treatment with 320 mg Folltropin-V. In parallel, 21 heifers were superstimulated in a conventional manner (Days 8 to 12) and were used as controls. The homogeneity of follicular inventories among Stage-groups occurred within 4 days of GnRH treatment for follicles ≥ 7 mm but only 2 days after follicular puncture for follicles 4 to 6 mm. In response to the follicular puncture, the mean number of follicles 4 to 6 mm increased in heifers of the punctured group (P < 0.01). Following the superstimulation, the follicular (P < 0.01) and ovulatory (P < 0.01) responses were higher in the punctured group than in the nonpunctured group. The in vivo production of transferable embryos in the punctured group was similar to that of the nonpunctured group but it was lower (P < 0.01) than in heifers of the control group. In conclusion, results from the present study indicate that regardless of the stage of the oestrous cycle, the homogeneity of follicular inventories following the follicular synchronization is obtained using GnRH treatment and follicular puncture. The in vivo production of embryos was severely compromised in the present study with heifers. Causes of such reduction in the in vivo production of embryos are still unknown.

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The effects of exogenous gonadotropins on oocyte and embryo quality in cattle

Cited by 97 publications

References 64 publications

Influence of maternal environment on the number of transferable embryos obtained in response to superovulatory FSH treatments in ewes

Influence of maternal environment on the number of transferable embryos obtained in response to superovulatory FSH treatments in ewes

Protocolos de produção in vitro de embriões na raça Gir

Superovulation following follicular synchronization with GnRH at random stages of the oestrous cycle in heifers

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