Factors influencing success of embryo transfer in sheep and goats

Armstrong, David T.; Evans, G.

doi:10.1016/0093-691x(83)90121-8

Cited by 124 publications

(68 citation statements)

References 8 publications

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“…The lower yield of transferable embryos recorded in ewes treated with daily FSH/LH ratio of 5.0 -1.0 -0.3 may have negatively influenced hormonal pattern and/or the physiological events connected to the embryo production. However, the mean number of transferable embryos produced in this experiment following the 3.4 -1.7 -0.8 FSH/LH treatment was equivalent to that reported in other breeds treated with ovine-FSH (Dingwall et al, 1993;Bari et al, 1999) but higher than for other hormonal treatments (Armstrong and Evans, 1983;Martemucci et al, 1988;Wierzchos et al, 1992;Scudamore et al, 1993;Boland et al, 1995).…”

Section: Discussionsupporting

confidence: 76%

Use of purified FSH and LH for embryo production, cryopreservation by conventional freezing or vitrification and transfer of embryos in dairy ewes

D’Alessandro¹,

Martemucci²

2003

Italian Journal of Animal Science

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Three experiments were carried out with the aim of evaluating the efficiency of techniques of in vivo production, storage and transfer of embryos in dairy sheep. Experiment I -For embryo production, thirty-one ewes were synchronized with FGA (vaginal sponges, 40 mg, 9 d) and PGF2α (ICI; 50 µg, 7 th d), and subdivided into three groups corresponding to the following superovulatory treatments over 3 days with purified gonadotrophic preparations: A) control, FSH/LH ratio = 1 (250 IU p-FSH : 250 UI p-LH); B) FSH/LH ratio = 2 (250 IU p-FSH : 125 IU p-LH) and daily FSH/LH ratio of 3.4 -1.7 -0.8 in the 3 days of treatment, respectively; C) FSH/LH ratio = 2 (250 IU p-FSH : 125 IU p-LH) and daily FSH/LH ratio of 5.0 -1.0 -0.3. On the 7 th day after oestrus and mating, ovarian response and embryo production were evaluated. Experiment II -Three freezing methods were evaluated based upon post-thaw embryo quality: CF) conventional slow freezing by 1.5 M ethylene glycol (EG); V-1) one-step vitrification based on exposure of the embryos to one solution (EG 7.15 M + ficoll 2.5 mM); V-3) vitrification in three steps, corresponding to three solutions at increasing concentration of glycerol (GLY) and EG (GLY 1.4 M; GLY 3.4 M + EG 1.4 M; GLY 4.6 M + EG 3.4 M). V-1) and V-3) frozen embryos were directly plunged in liquid nitrogen. At thawing, embryo viability was evaluated on the basis of morphological features. Experiment III -For embryo transfer, a total of 26 recipient ewes were synchronized with donors. On the 7 th d from oestrus, 11 recipient ewes received fresh embryos (Group FE -control) and 15 recipients received vitrified-thawed embryos (Group VTE). Each recipient received 2 embryos. Superovulatory treatment B) significantly advanced the onset of oestrus compared to the control (27.3 vs 34.7 h; P<0.05). Ovulation rate did not differ among the groups (6.5 to 10.8). Transferable embryos in Group B) (7.2) resulted similar to Group A) (5.3) and significantly (P<0.05) different when compared to Group C) (3.2). V3-method resulted in the highest (P<0.01) transferable embryos (74.5%) compared to CF-and V1-methods. After transfer, in FE and VTE recipient ewes were comparable in fertility rates (72.7 vs 73.3%; P>0.05) and embryo survival (63.6 vs 56.7%; P>0.05). In conclusion, the results demonstrated that treatments B) and C) did not improve superovulatory response compared to A); for embryo cryopreservation the V3 method can successfully be used for embryo transfer in ewes. (27,3 vs 34,7 ore; P<0,05). Il tasso di ovulazione non è stato influenzato dal trattamento (6,5 -10,8; P>0,05). La produzione di embrioni trasferibili registrata nel Gruppo B) (7,2) è stata similare al controllo (Gruppo A, 5,3) e maggiore rispetto al trattamento C) (3,2; P<0,05

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Section: Discussionsupporting

confidence: 76%

Use of purified FSH and LH for embryo production, cryopreservation by conventional freezing or vitrification and transfer of embryos in dairy ewes

D’Alessandro¹,

Martemucci²

2003

Italian Journal of Animal Science

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“…Although some evidence has been observed of an alteration in oocyte activation and in patterns of oocyte protein synthesis, or follicular steroidogenesis capacity [24] and ovulation time [39], the reason why FSH alone produces better quality embryos than eCG is not fully understood. Armstrong [2] has suggested that acceleration of follicle development during superovulatory treatment can occur before complete growth to allow completion of maturational process of cytoplasmic oocyte and granulosa cells. Driancourt and Fry [12] have shown that eCG could determine variations in the morphological features of the preovulatory follicles, altering the size and number of granulosa cells which play an essential role in the transport of regulatory signals and metabolic substrates to full oocyte maturation.…”

Section: Discussionmentioning

confidence: 99%

Sheep embryos derived from FSH/eCG treatment have a lower in vitro viability after vitrification than those derived from FSH treatment

et al. 2001

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-In the non breeding period, the effect of two superovulatory treatments (eCG/FSH in single dose or FSH alone in four decreasing doses) on the production of embryo quality following in vitro viability after vitrification procedures was investigated using forty-four adult Sarda breed ewes. In sheep treated with eCG/FSH, the mean number of corpora lutea was significantly (P < 0.05) higher (11.8 ± 4.0 vs. 8.05 ± 3.8), although the recovery rate was significantly (P < 0.01) lower (74.6 vs. 59.9) than with FSH alone. After vitrification (ethylene glycol and glycerol) was repeated three times, the rates of re-expansion at first and second warming were significantly (P < 0.01) higher in embryos derived from FSH alone than in those with both gonadotrophins (94.9 and 41.9 vs. 72.8 and 18.6) and after the last vitrification the hatched blastocyst rates were 22.5 and 7.6. After differential stain, blastocysts derived from FSH alone showed a mean number of cells significantly higher than blastocysts from eCG/FSH (184.2 vs. 157.7). It was concluded that superovulatory treatment with eCG/FSH may increase the ovarian responses compared with FSH alone, but these embryos showed a reduction in viability rates after repeated vitrification. superovulation / embryo quality / ovine / vitrification / viabilityRésumé -Les embryons ovins obtenus après un traitement de superovulation associant FSH et eCG ont une viabilité in vitro plus faible après vitrification que les embryons obtenus avec un traitement séquentiel de FSH. Pendant la saison non reproductive, on a évalué, chez 44 brebis adultes de race Sarde, l'effet de deux traitements de superovulation (le premier avec les eCG/FSH en une seule administration, le deuxième avec la FSH administrée en quatre doses décroissantes) sur la qualité des embryons produits et sur la viabilité in vitro après vitrification. Dans le groupe traité avec les eCG/FSH, le nombre moyen d'ovulations était plus élevé (11,8 ± 4,0 vs. 8,05 ± 3,8, P < 0,05) tandis que le taux de récupération était plus faible (74,6 vs. 59,9, P < 0,01) par rapport au groupe traité avec la FSH seule. Les embryons ont suivi 3 vitrifications successives (éthylène glycol et glycérol). Reprod. Nutr. Dev. 41 (2001) [239][240][241][242][243][244][245][246] 239

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“…Pregnant mare serum gonadotrophin (PMSG) [6], pituitary extracts of different origin [28,69,96] and human menopausal gonadotrophin [92] are commonly used for superovulation in sheep. The biological properties of the gonadotrophins used for superovulation have been described in detail elsewhere [13]; for review see [45] [67] or later, during early embryonic development as a result of unbalanced hormonal profiles [3,51] [66], association of these two gonadotrophins [91], single versus multiple injections [30,64], or inclusion of GnRH or growth hormone in the treatments [36,111].…”

Section: Superovulationmentioning

confidence: 99%