Effect of season and gonadotrophin preparation on superovulatory response and embryo quality in Portuguese Black Merinos

Bettencourt, E.M.; Bettencourt, C. M. V.; Silva, J. Chagas e; Ferreira, Paulo Michel Pinheiro; Manito, C.I.; Matos, Cácia Mendes; Romão, R.; Rocha, António

doi:10.1016/j.smallrumres.2007.05.001

Cited by 22 publications

(31 citation statements)

References 22 publications

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“…Multiple ovulation is mainly acquired using FSH, although some programs still use equine chorionic gonadotrophin (eCG) alone or associated with FSH [52,[64][65][66]. Despite the increase in the ovulation rate, the number of embryos obtained with eCG is often lower than expected.…”

Section: Estrus Synchronization and Superovulation Programsmentioning

confidence: 99%

“…The short half-life of FSH implies, however, a 12-hour interval of repeated administration for a period of 4 days [69]. FSH may be of porcine (pFSH) [66,70] or ovine (oFSH) source [52,66,71]. Usually, the treatment begins 72 hours before the withdrawal of exogenous progesterone.…”

Section: Estrus Synchronization and Superovulation Programsmentioning

confidence: 99%

“…The response to this treatment is dependent on the number of applied doses [72,73] and used protocol (constant or decreasing doses) [51,71,73]. There are also intrinsic factors that may affect the superovulatory response in small ruminants, namely, breed, age, nutrition, and reproductive status, the latter being directly conditioned by the reproductive seasonality in this species [51,66]. In addition, individual differences are of crucial importance in the embryo development process [51].…”

Section: Estrus Synchronization and Superovulation Programsmentioning

confidence: 99%

“…Additionally, the influence of seasonality in response to superovulation treatment is obviously more noticeable in breeds located in higher latitudes, mainly affecting the viability of obtained embryos [77,78]. Conversely, in temperate regions, a less pronounced seasonality has been identified without differences in the superovulatory response between animals treated inside or outside the breeding season [66,[79][80][81]. However, embryos collected after the administration of the treatment within the breeding season had higher quality [66,78].…”

Section: Estrus Synchronization and Superovulation Programsmentioning

confidence: 99%

“…The application of a modified laparoscopic technique allowed repeated recoveries in the same ewe, keeping a recovery rate lower than the one obtained with laparotomy, hence offering no commercial advantage [98]. In a conservation program, the total number of embryos recovered and frozen after a MOET program is approximately 7 and 6 per superovulated ewe, respectively, associated with an embryo recovery rate between 60 and 70% [66].…”

Section: Oocyte Fertilization and Embryo Recoverymentioning

confidence: 99%

See 4 more Smart Citations

Cryopreservation of Sheep Produced Embryos – Current and Future Perspectives

Romão¹,

Marques²,

Bettencourt³

et al. 2016

Insights From Animal Reproduction

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Due to economical and scientific limitations, sheep embryo reproductive technologies are less commercially applied than in other animal species. However, it is very clear that, in the near future, those techniques are expected to have a central role in animal production as a consequence of genetic and reproductive demands. One drawback is that results obtained after sheep embryo cryopreservation are unattractive for commercial purposes. It is expected that a successful cryopreservation of sheep embryos can push forward all other reproductive biotechnologies in this species, such as multiple ovulation and embryo transfer (MOET), artificial insemination, or in vitro production of embryos. This paper tries to discuss the current and future perspectives of cryopreservation of in vivo-and in vitro-produced sheep embryos concerning advantages and limitations for its practical use and possible solutions for improving methods to allow a higher survival rate of cryopreserved embryos.

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Section: Estrus Synchronization and Superovulation Programsmentioning

confidence: 99%

Section: Estrus Synchronization and Superovulation Programsmentioning

confidence: 99%

Section: Estrus Synchronization and Superovulation Programsmentioning

confidence: 99%

Section: Estrus Synchronization and Superovulation Programsmentioning

confidence: 99%

Section: Oocyte Fertilization and Embryo Recoverymentioning

confidence: 99%

See 3 more Smart Citations

Cryopreservation of Sheep Produced Embryos – Current and Future Perspectives

Romão¹,

Marques²,

Bettencourt³

et al. 2016

Insights From Animal Reproduction

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A study on superovulation using FSH and eCG in Awassi ewes

Azawi

Al-Mola

2009

Trop Anim Health Prod

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A study on the effect of GnRH administration on the ovarian response and laparoscopic intrauterine insemination of Awassi ewes treated with eCG to induce superovulation

Azawi

Al-Mola

2011

Trop Anim Health Prod

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The effect of GnRH administration on superovulatory response of ewes treated with equine chorionic gonadotrophin (eCG) in breeding and nonbreeding seasons and the contribution of laparoscopic insemination to the improvement of fertilization and embryo recovery were investigated. Twenty-four nonpregnant Awassi ewes of 3-4 years of age were randomly allocated into two groups (n = 12). Each ewe was treated with a progesterone impregnated intravaginal sponge for 12 days. The following superovulation treatment was used: ewes of group 1 received 1,200 IU of eCG once as an intramuscular injection 48 h prior to sponge withdrawal; ewes of group 2 also received 1,200 IU of eCG once as an intramuscular injection, 48 h prior to sponge withdrawal and after 24 h of sponge removal. Ewes were injected with 80 μg of GnRH. Ewes of groups 1 and 2 were further subdivided into four equal groups (n = 6). Subgroups A and C (superovulated with eCG and eCG plus GnRH, respectively) were mated naturally at least two times with Awassi rams of proven fertility at 8-h intervals. Subgroups B and D (same as A and C) had intrauterine insemination at 44-46 h after sponge removal, under laparoscopic visualization of uterine horns, depositing 1 ml of diluted semen containing 100 × 10(6) motile sperm in the distal portion of each uterine horn. Ovarian response was assessed by determining the number of corpora lutea by laparoscopy at day 6 after mating. Embryo recovery was performed by using a semi-laparoscopic flushing procedure in both uterine horns. Results of the present study showed that ewes treated in breeding season with eCG plus GnRH has a higher number (P < 0.05) of corpora lutea than eCG alone as 7.33 ± 0.54 and 4.33 ± 0.39, respectively. There was no significant difference in the number of corpora lutea in nonbreeding season when ewes treated with eCG and eCG plus GnRH. The number of unovulated follicles was significantly higher (P < 0.05) in eCG treated ewes than in ewes treated with eCG plus GnRH, both in the breeding and nonbreeding seasons. The number of recovered embryos from ewes treated with eCG plus GnRH and eCG differ significantly (P < 0.05) as 4.32 ± 0.56 and 1.06 ± 0.26, respectively, in the breeding seasons. No significant difference was observed when these hormones used for superovulation in the nonbreeding season. A higher number of unfertilized ova (P < 0.05) was observed in ewes when naturally inseminated than in ewes inseminated using the intrauterine laparoscopic technique. Higher rate of embryo recovery (P < 0.05) was achieved when ewes were inseminated via intrauterine (4.66 ± 0.66) compared with ewes naturally mated (2.16 ± 0.74). The fertilization rate in ewes inseminated intrauterine using laparoscopic techniques and naturally mated were 91.5% and 44.8%, respectively. Fertilization failure in ewes inseminated intrauterine using laparoscopic techniques and naturally mated were 8.4% and 55.2%, respectively. It could be concluded that administration of GnRH 24 h after sponge removal increased ovulation rate of Awassi ...

show abstract

Effect of season and gonadotrophin preparation on superovulatory response and embryo quality in Portuguese Black Merinos

Cited by 22 publications

References 22 publications

Cryopreservation of Sheep Produced Embryos – Current and Future Perspectives

Cryopreservation of Sheep Produced Embryos – Current and Future Perspectives

A study on superovulation using FSH and eCG in Awassi ewes

A study on the effect of GnRH administration on the ovarian response and laparoscopic intrauterine insemination of Awassi ewes treated with eCG to induce superovulation

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