Ovulation of aged follicles does not affect embryo quality or fertility after a 14-day progestagen estrus synchronization protocol in ewes

Evans, A.C.O.; Flynn, Jeremy D.; Quinn, K.; Duffy, Patrick E.; Quinn, Patrick G.; Madgwick, Suzanne; Crosby, T.F.; Boland, M.P.; Beard, A.P.

doi:10.1016/s0093-691x(01)00619-7

Cited by 48 publications

(30 citation statements)

References 37 publications

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“…In cattle, oocytes from the dominant follicles with a prolonged lifespan undergo premature maturation leading to decreased fertility (Revah & Butler 1996). In contrast, Evans et al (2001) demonstrated that ovine oocytes from follicles with a prolonged lifespan could be fertilized and produce good quality embryos. The discrepancies above are likely due to different hormonal treatments and/or species.…”

Section: Discussionmentioning

confidence: 99%

Markers of ovarian antral follicular development in sheep: comparison of follicles destined to ovulate from the final or penultimate follicular wave of the estrous cycle

Seekallu¹,

Toosi²,

Grazul-Bilska³

et al. 2010

Reproduction

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Treatment of non-prolific western white-faced ewes with prostaglandin F 2a (PGF 2a ) and medroxyprogesterone acetate (MAP) increases the ovulation rate as a result of ovulations from the penultimate wave in addition to the final wave of the cycle. The objective of the current study was to evaluate the expression of markers of vascularization/angiogenesis, a marker of intercellular communication, and cellular proliferation and apoptosis in follicles from the penultimate and final waves. On day 8 of the estrous cycle, 15 ewes were administered a single injection of PGF 2a and an intravaginal MAP sponge, which remained in place for 6 days. Two days after sponge removal, ovaries which contained follicles from the penultimate and final waves were collected and processed for immunohistochemistry followed by image analysis, and for quantitative real-time RT-PCR. Expression of factor VIII (marker of vascularization), proliferating cell nuclear antigen, and GJA1 (Cx43; marker of gap junctional communication) was greater (P!0.05) in follicles from the final wave compared with follicles from the penultimate wave. For theca cells, mRNA expression for vascular endothelial growth factor (VEGF) was greater (P!0.05) and tended to be greater (P%0.1 and R0.05) for GJA1 and endothelial nitric oxide synthase in follicles from the final wave compared with follicles from the penultimate wave. For granulosa cells, the mRNA expression for GJA1 was greater (P!0.05) and tended to be greater (P%0.1 and R0.05) for VEGF in follicles from the final wave compared with follicles from the penultimate wave.In conclusion, extension of the lifespan of follicles in the penultimate wave reduces follicular viability in the ewe.

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Section: Discussionmentioning

confidence: 99%

Markers of ovarian antral follicular development in sheep: comparison of follicles destined to ovulate from the final or penultimate follicular wave of the estrous cycle

Seekallu¹,

Toosi²,

Grazul-Bilska³

et al. 2010

Reproduction

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“…Proven protocols for estrus synchronization in the ewe consist of a long-term intravaginal treatment with progestagens or progesterone for 12-14 days (Abecia et al, 2011;Viñoles et al, 2001), resulting in a high percentage of animals in estrus but a variable fertility (Menchaca and Rubianes, 2004). Towards the end of a long-term treatment subluteal progestagen concentrations were measured (Greyling et al, 1994) leading to an increase in LH pulse frequency and a prolonged persistence and aging of the ovulatory follicles (Evans et al, 2001;Flynn et al, 2000;Leyva et al, 1998b;Menchaca and Rubianes, 2004) which may negatively affect fertility (Evans, 2003). Moreover, progestagen treatment is also known to impair sperm transport and survival reducing the number of fertilized ova (Allison and Robinson, 1970;Hawk and Conley, 1972).…”

Section: Introductionmentioning

confidence: 99%

Comparison of 6-day progestagen treatment with Chronogest® CR and Eazi-breed™ CIDR® G intravaginal inserts for estrus synchronization in cyclic ewes

Fleisch¹,

Werne²,

Heckendorn³

et al. 2012

Small Ruminant Research

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The aim of this study was to compare the efficacy of two different short-term progestagen treatments for estrus synchronization in cyclic ewes. A total of 292 ewes of 3 flocks (A-C) on different farms were treated for 6 days with Eazi-breed™ CIDR® G (n = 145) or Chronogest® CR (n = 147) vaginal inserts in combination with 0.125 mg Cloprostenol and 300IU eCG at device removal. Blood samples were taken for progesterone (P4) determination at insert application and removal as well as 14 days later. One day after insert removal rams fitted with marking harnesses were joined to ewes for 35 days and marked ewes recorded daily. Lambing data were recorded and fertility to first service period and overall assessed. Results show that 24-96 h after insert removal 98.8% and 89.4% of the synchronized ewes in the flocks B and C were in estrus. Estrus response was not affected by the type of progestagen treatment and was lower (P < 0.05) in nulli-(82.1%) than in pluriparous (97.5%) ewes. Type of progestagen treatment did not affect fertility, but flock and parity influenced the percentage of ewes that lambed as well as the lambing rate. Overall more ewes (P < 0.001) lambed in flock A compared to flocks B and C (93.0 vs. 72.5 and 59.1%). In nulliparous animals the percentage of ewes that lambed was higher to the first service (P < 0.05) period but lower (P < 0.001) to the overall service period compared to pluriparous animals (51.5% vs. 49.3% and 64.7% vs. 84.2%). Lambing rates were higher in flock A than in flocks B and C to first service period and overall (1.3 ± 1.4, 0.9 ± 1.0, and 0.7 ± 1.0, P < 0.01 and 1.9 ± 1.1, 1.3 ± 0.9, and 1.0 ± 1.0, P < 0.001) and in nulliparous overall lower than in pluriparous ewes (1.1 ± 1.1 and 1.6 ± 1.1, P < 0.01). Serum P4 concentrations measured 14 days after insert removal were higher in the Chronogest® CR than in the Eazi-breed™ CIDR® G group (6.8 ± 4.1 ng/mL vs. 5.7 ± 3.3 ng/mL). Ewes of flock A had higher P4 values compared to ewes of flocks B and C (8.3 ± 4.1 ng/mL vs. 4.5 ± 1.5 ng/mL and 3.8 ± 1.7 ng/mL) and nulliparous lower P4 concentrations than pluriparous ewes (4.5 ± 2.2 ng/mL vs. 6.7 ± 4.0 ng/mL). In conclusion, a 6-day treatment with Chronogest® CR and Eazi-breed™ CIDR® G with prostaglandin and eCG at insert removal resulted in high estrus response and similar fertility in cyclic ewes. AbstractThe aim of this study was to compare the efficacy of two different short-term progestagen treatments for estrus synchronization in cyclic ewes. A total of 292 ewes 72.5 and 59.1%). In nulliparous animals the percentage of ewes that lambed was higher to the first service (P<0.05) period but lower (P<0.001) to the overall service period compared to pluriparous animals (51.5 vs. 49.3% and 64.7 vs. 84.2%).Lambing rates were higher in flock A than in flocks B and C to first service period and overall (1.3±1.4, 0.9±1.0, 0.7±1.0, P<0.01 and 1.9±1

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“…In ewes, progestagens are widely used to synchronize estrus, and typically result in approximately 90% estrus exhibition within a 24-hour period and conception rate of 70-80% (Evans et al, 2001). Among the various methods or biotechnologies, which can be employed to control the reproductive cycle of the ewes is the use of synthetic progestins, like melengestrol acetate (MGA), which represents an ideal choice for this type of production in rural areas, where the farmers do not have the economic resource and sufficient technology (Álvarez and Ducoing, 2005).…”

Section: Introductionmentioning

confidence: 99%

Influence of short- and long-term administration of Melengestrol acetate on estrus activity and reproductive performance of nulliparous Barki ewes

Farrag¹,

El-Hamid²,

El-Hawy³

et al. 2018

IJEAB

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Ovulation of aged follicles does not affect embryo quality or fertility after a 14-day progestagen estrus synchronization protocol in ewes

Cited by 48 publications

References 37 publications

Markers of ovarian antral follicular development in sheep: comparison of follicles destined to ovulate from the final or penultimate follicular wave of the estrous cycle

Markers of ovarian antral follicular development in sheep: comparison of follicles destined to ovulate from the final or penultimate follicular wave of the estrous cycle

Comparison of 6-day progestagen treatment with Chronogest® CR and Eazi-breed™ CIDR® G intravaginal inserts for estrus synchronization in cyclic ewes

Influence of short- and long-term administration of Melengestrol acetate on estrus activity and reproductive performance of nulliparous Barki ewes

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