Time of ovulation in merino ewes superovulated with PMSG and FSH-P

Ryan, J. P.; Hunton, J. R.; Maxwell, W.M.C.

doi:10.1071/rd9920091

Cited by 9 publications

(4 citation statements)

References 11 publications

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“…In recent research (Deligiannis et al 2005;Bettencourt et al 2008), efforts are directed at improving the superovulation efficiency and the shedding of high-quality oocytes. Methods of superovulation have been improved by using regimens that combine both equine chorionic gonadotrophin (eCG) and GnRH (gonadotrophin releasing hormone) (Ryan et al 1992;Naqvi and Gulyani 1999) to reduce the incidence of anovulatory and cystic follicles and to increase the proportion of developing follicles that ovulate. Increased ovulation and fertilization rates have been reported following the administration of GnRH in conjunction with eCG to superovulated ewes (GonzalezBulnes et al 2004).…”

Section: Introductionmentioning

confidence: 99%

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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 ...

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Section: Introductionmentioning

confidence: 99%

“…Increased ovulation and fertilization rates have been reported following the administration of GnRH in conjunction with eCG to superovulated ewes (GonzalezBulnes et al 2004). Furthermore, the addition of GnRH to eCG superovulatory regimens has been used to control time of ovulation in superovulated ewes (Ryan et al 1992).…”

Section: Introductionmentioning

confidence: 99%

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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“…For a long time, eCG was used as an alternative FSH hormone for superovulation induction by improving the process of follicle recruitment in several mammal models [68]. Indeed, it was successfully used in small mammals, such as mice rats [69] rats alone [70], medium-large sized mammals such as sheep [71][72][73], goats [74], cows [75], mares [76], and pigs [77].…”

Section: Discussionmentioning

confidence: 99%

Equine Chorionic Gonadotropin as an Effective FSH Replacement for In Vitro Ovine Follicle and Oocyte Development

Berardino

Peserico

Capacchietti

et al. 2021

IJMS

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The use of assisted reproductive technologies (ART) still requires strategies through which to maximize individual fertility chances. In vitro folliculogenesis (ivF) may represent a valid option to convey the large source of immature oocytes in ART. Several efforts have been made to set up ivF cultural protocols in medium-sized mammals, starting with the identification of the most suitable gonadotropic stimulus. In this study, Equine Chorionic Gonadotropin (eCG) is proposed as an alternative to Follicle Stimulating Hormone (FSH) based on its long superovulation use, trans-species validation, long half-life, and low costs. The use of 3D ivF on single-ovine preantral (PA) follicles allowed us to compare the hormonal effects and to validate their influence under two different cultural conditions. The use of eCG helped to stimulate the in vitro growth of ovine PA follicles by maximizing its influence under FBS-free medium. Higher performance of follicular growth, antrum formation, steroidogenic activity and gap junction marker expression were recorded. In addition, eCG, promoted a positive effect on the germinal compartment, leading to a higher incidence of meiotic competent oocytes. These findings should help to widen the use of eCG to ivF as a valid and largely available hormonal support enabling a synchronized in vitro follicle and oocyte development.

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“…Injection of Merino ewes with 100µg of GnRH 24 hours after the removal of MAP sponge inserted in the ewes for 12 days caused advancement in the time of ovulation during breeding season but showed no effect on the timing of ovulation during anestrous season (Ryan et al, 1992). Also, Jabbour and Evans (1991) reported a reduction in the time to estrus in cyclic Merino ewes when they were injected with 100µg of GnRH 12 hours after the removal of MAP sponge inserted in the ewes for 12 days.…”

Section: Use Of Exogenous Hormonesmentioning

confidence: 99%

Effect of Nutrition, Lactation and Gonadotropin Stimulation on Ram-Induced LH Surge and Subsequent Fertility in Early Post-Partum Ewes during Seasonal Anestrous

Adebiyi¹

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Time of ovulation in merino ewes superovulated with PMSG and FSH-P

Cited by 9 publications

References 11 publications

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

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

Equine Chorionic Gonadotropin as an Effective FSH Replacement for In Vitro Ovine Follicle and Oocyte Development

Effect of Nutrition, Lactation and Gonadotropin Stimulation on Ram-Induced LH Surge and Subsequent Fertility in Early Post-Partum Ewes during Seasonal Anestrous

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