Superovulatory response in anestrous ewes is affected by the presence of a large follicle

Rubianes, E.; Ibarra, D.; Ungerfeld, Rodolfo; Carbajal, B.; Castro, T. de

doi:10.1016/0093-691x(94)00039-w

Cited by 43 publications

(29 citation statements)

References 16 publications

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“…Consistently higher ovulatory responses were elicited when the treatment began on the day of (Nasser et al. 1993; Adams 1994; Rubianes et al. 1995; Mapletoft et al.…”

Section: Introductionmentioning

confidence: 76%

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Ovarian Responses, Hormonal Profiles and Embryo Yields in Anoestrous Ewes Superovulated with Folltropin®‐V after Pretreatment with Medroxyprogesterone Acetate‐releasing Vaginal Sponges and a Single Dose of Oestradiol‐17β

Bartlewski¹,

Alexander²,

Rawlings³

et al. 2007

Reprod Domestic Animals

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In ruminants, superovulatory treatments started at the time of follicular wave emergence result in greater and less variable ovulatory responses and embryo yields compared with the treatments begun in the presence of a large growing antral follicle(s) from the previous waves. The progesterone-oestradiol treatment is routinely used for follicular wave synchronization in cattle. The main objective of this study was to characterize the ovarian responses, hormonal profiles and in vivo embryo production in anoestrous Rideau Arcott ewes (May-June), which were superovulated after pretreatment with medroxyprogesterone acetate (MAP)-releasing intravaginal sponges and a single dose of oestradiol-17beta (E(2)-17beta). Six days after insertion of MAP sponges, eight ewes were given an i.m. injection of 350 microg of E(2)-17beta (E(2)-17beta-treated ewes); 10 ewes were given an i.m. injection of vehicle (control ewes). Multiple-dose Folltropin-V treatment, followed by the bolus injection of GnRH (50 microg i.m.), began 6 days after E(2)-17beta/vehicle injection. Transrectal ovarian ultrasonography revealed that: (i) the interval between E(2)-17beta/vehicle injection and regression of all follicles > or =5 to 3 mm in diameter was shorter (p < 0.01; 2.6 +/- 0.4 vs 4.8 +/- 0.6 days respectively); and (ii) the interval between injection and emergence of the next follicular wave was longer (p < 0.05; 5.4 +/- 0.3 vs 1.2 +/- 0.4 days, respectively) in E(2)-17beta-treated than in control ewes. During the 6 days after injection, the mean FSH peak concentration and basal FSH concentration were lower (p < 0.01) in E(2)-17beta-treated ewes. The mean ovulation rate and the number of recovered embryos did not differ (p > 0.05) between the two groups of ewes. However, the number of luteinized unovulated follicles per ewe, and the variability in the number of luteal structures and overall embryo yield were less (p < 0.05) in E(2)-17beta-treated compared with control ewes. In conclusion, the MAP-E(2)-17beta pretreatment significantly reduced the variability in ovarian responses and embryo yields, without affecting the embryo production in superovulated anoestrous ewes.

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“…Consistently higher ovulatory responses were elicited when the treatment began on the day of (Nasser et al. 1993; Adams 1994; Rubianes et al. 1995; Mapletoft et al.…”

Section: Introductionmentioning

confidence: 76%

“…The ovarian response and embryo yield after superovulation in sheep are highly variable (Gonzales‐Bulnes et al. 2004), particularly during seasonal anoestrus (Rubianes et al. 1995), which limits the application of superovulation in the embryo transfer programmes and experimental work.…”

Section: Introductionmentioning

confidence: 99%

Ovarian Responses, Hormonal Profiles and Embryo Yields in Anoestrous Ewes Superovulated with Folltropin®‐V after Pretreatment with Medroxyprogesterone Acetate‐releasing Vaginal Sponges and a Single Dose of Oestradiol‐17β

Bartlewski¹,

Alexander²,

Rawlings³

et al. 2007

Reprod Domestic Animals

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“…These results were in agreement with Samartzi et al (1995) that used varied doses of eCG. The presence of a large growing follicle at the time of a superovulatory dosage of eCG (Rubianes et al 1995) has been reported to decrease ovarian response to LH surge. Bettencourt et al (2008) have also observed an increased ovulation rate following GnRH administration.…”

Section: Discussionmentioning

confidence: 98%

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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“…The major factor leading to the variable ovulation rate and embryo output currently seems to be the follicular status of the donor at the onset of superovulatory treatment (Gonzalez-Bulnes et al, 2004). So for example, the presence of a dominant follicle at the onset of superovulation has been reported to decrease the ovarian response in small ruminants (Rubianes et al, 1995;Lopez-Sebastian et al, 1999;Rubianes & Menchaca, 2003). It is assumed that by lowering the LH concentration, the establishment of a dominant follicle could be avoided, and therefore more follicles will have the opportunity to develop and ovulate under (Gonzalez-Bulnes et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

Superovulatory response in Boer goats pre-treated with a GnRH agonist outside the natural breeding season

Lehloenya

Greyling²,

Schwalbach³

et al. 2007

SA J. An. Sci.

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The aim of this study was to evaluate the ovarian response and embryo recovery rates in Boer goat does superovulated with pFSH following a pre-treatment with a GnRH agonist (GnRHa) outside the natural breeding season. Oestrus was synchronised in 22 does with CIDR's for 17 days, and these were superovulated with a total dose of 200 mg pFSH/doe administered i.m. in seven dosages, at 12 h intervals, starting 48 h prior to CIDR removal (the first dose being 50 mg and all others 30 mg each). Half of the does (n = 11; treatment group) received GnRHa (Lucrin®) for seven days, starting on day 7 of CIDR insertion, while the other half (n = 11; control group) received no GnRHa. Cervical inseminations with fresh undiluted semen were performed 36 h and 48 h following CIDR removal and the embryos surgically flushed six days after the second AI. The oestrous response, onset-and duration of the induced oestrous period did not differ significantly between groups. There were also no significant differences between pFSH (21.3 ± 5.9) and pFSH/GnRHa (16.1 ± 7.0) treatments, with respect to the mean ovulation rate per donor. However, the mean total number of structures recovered (unfertilised ova and embryos) per doe flushed and the fertilisation rates (%) were significantly lower in the pFSH/GnRHa treated does (12.7 ± 6.0; 11.5 ± 5.3; 81.6 ± 32.2%, respectively), compared to the control group (17.5 ± 4.5; 16.5 ± 6.1; 92.6 ± 19.6%, respectively). In addition, the mean number and percentage of transferable embryos were also significantly lower in the pFSH/GnRHa treated does (4.3 ± 4.0 and 32.7 ± 36.9%), compared to the control does (13.1 ± 5.3 and 75.2 ± 26.8%, respectively). However, no significant differences were recorded in the mean total number of unfertilised ova/doe between groups. The pFSH/GnRHa treatment resulted in a higher number of degenerated embryos per donor (6.9 ± 4.5) compared to the control (3.2 ± 4.2). The pre-treatment with a GnRHa to the pFSH superovulation protocol outside their natural breeding season seemed to be detrimental to embryo production and quality in Boer goats, and is not warranted.

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Superovulatory response in anestrous ewes is affected by the presence of a large follicle

Cited by 43 publications

References 16 publications

Ovarian Responses, Hormonal Profiles and Embryo Yields in Anoestrous Ewes Superovulated with Folltropin®‐V after Pretreatment with Medroxyprogesterone Acetate‐releasing Vaginal Sponges and a Single Dose of Oestradiol‐17β

Ovarian Responses, Hormonal Profiles and Embryo Yields in Anoestrous Ewes Superovulated with Folltropin®‐V after Pretreatment with Medroxyprogesterone Acetate‐releasing Vaginal Sponges and a Single Dose of Oestradiol‐17β

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

Superovulatory response in Boer goats pre-treated with a GnRH agonist outside the natural breeding season

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