RESUMO
This study assessed the efficiency of cervical relaxation protocol using none, half or full dose (1.0 mg) of oestradiol benzoate in Dorper ewes subjected to non-surgical embryo recovery (NSER). Thirty-six pluriparous ewes received progestogen sponge (60 mg) for 9 days plus eCG administration (300 IU i.m.) 24 hr before sponge removal. Ewes were not mated and were randomly assigned to receive at 16 hr before NSER 37.5 µg d-cloprostenol i.m. and different doses of oestradiol benzoate: 0.0 mg (0EB group; n = 12); 0.5 mg (0.5EB group; n = 12) or 1.0 mg of oestradiol (1.0EB group, n = 12). All ewes received oxytocin (50 IU) i.v. 20 min before NSER, which was performed 8 days after sponge removal. Corpora lutea were counted by transrectal ultrasonography 24 hr before NSER. After procedure, the ewes were kept in natural breeding period to check their post-NSER fertility. NSER was performed in 91.7% (33/36) of the animals with overall fluid recovery efficiency over 97% (p > .05). The cervical transposing with Hegar dilator was longer (p < .05) in 0EB (4.2 ± 0.3 min) compared to 0.5EB (1.7 ± 0.3 min) and 1.0EB group (1.5 ± 0.3 min). The cervical transposing with mandrel/catheter was longer (p < .05) in 0EB (2.4 ± 0.5 min) than 1.0EB group (1.3 ± 0.5 min). Overall duration of uterine flushing was 25.4 min with structure recovery rate of 43.5%, with no difference among groups (p > .05). The post-NSER fertility was higher (p < .05) in 0.0EB (90%) than 0.5EB group (36.4%). In conclusion, NSER can be successfully performed in Dorper ewes by using a cervical relaxation protocol without oestradiol benzoate.
Assuntos
Estradiol/análogos & derivados , Carneiro Doméstico , Coleta de Tecidos e Órgãos/veterinária , Animais , Colo do Útero/efeitos dos fármacos , Transferência Embrionária/métodos , Transferência Embrionária/veterinária , Embrião de Mamíferos , Estradiol/farmacologia , Sincronização do Estro , Feminino , Fertilidade , Coleta de Tecidos e Órgãos/métodosRESUMO
The objective of this study was to assess the effect of the duration of progesterone-based estrus induction protocols on preovulatory follicular dynamics, ovulatory response, and embryo yield after non-surgical embryo recovery (NSER) in Lacaune ewes. Females received acetate medroxyprogesterone intravaginal sponges for six (G-6; nâ¯=â¯14) or nine (G-9; nâ¯=â¯14) days plus d-cloprostenol and eCG 24â¯h before sponge removal (Day 0). Preovulatory follicular dynamics and the luteal characteristics are evaluated by B-mode and Color-Doppler ultrasonography. NSER was performed five to six days after ovulation. The estrous behavior rate was 85.7% for both groups, and the percentage of ewes that ovulated was 92.9% in G-6 and 100% in G-9. The day of wave emergence (relative to Day 0) did not differ (Pâ¯>â¯0.05) between G-6 (-3.0⯱â¯0.5) and G-9 (-4.2⯱â¯0.5). The number of follicles of size 4.1-5.0â¯mm was higher (Pâ¯<â¯0.05) in G-9 (1.4⯱â¯0.2) compared to G-6 (0.8⯱â¯0.2) during the Days -4 to 0. At NSER, the transcervical penetration rate was 95.2% (20/21) and its duration time was lower (Pâ¯<â¯0.05) in G-9 (3.4⯱â¯0.6â¯min) than in G-6 (7.2⯱â¯1.3â¯min). The number of ovulations and viable embryos was higher (Pâ¯<â¯0.05) in G-9 (2.9⯱â¯0.3 and 1.3⯱â¯0.4, respectively) than in G-6 (1.9⯱â¯0.3 and 0.4⯱â¯0.2, respectively). In conclusion, the 9-day protocol promoted higher ovulation rate and embryo yield; moreover, the cervical dilation treatment allowed NSER in a high percentage of Lacaune ewes.
Assuntos
Sincronização do Estro/efeitos dos fármacos , Folículo Ovariano/fisiologia , Ovulação/fisiologia , Ovinos/fisiologia , Coleta de Tecidos e Órgãos/veterinária , Animais , Esquema de Medicação , Embrião de Mamíferos , Feminino , Acetato de Medroxiprogesterona/administração & dosagem , Acetato de Medroxiprogesterona/farmacologia , Ovinos/embriologia , Coleta de Tecidos e Órgãos/métodosRESUMO
Nearly three years ago our research team published a review of intrinsic determinants and predictors of superovulatory responses in ewes (18th International Congress on Animal Reproduction, Tours, France; 26-30 June 2016; Theriogenology 2016;86:130-143). Heres a summary of major advances in superovulatory treatments of ewes reported over the last three years and of some most anticipated future directions. The rate of genetic improvement within a synthetic population of animals is significantly enhanced by an application of superovulation and embryo transfer. However, the sheep industry has progressed rather slowly in terms of implementing these technologies in comparison to other species although sheep have been used in many studies that paved the way to the development of modern assisted reproductive technologies (ARTs). Recently, several improvements in determining ovarian responses and non-invasively collecting/transferring embryos have been reported but some most frustrating problems associated with hormonal ovarian superstimulation (e.g., unpredictable and highly variable individual responses) remain unresolved. This warrants continued studies of both the physiological basis of and novel approaches to superovulatory treatments in sheep.
Assuntos
Animais , Melhoramento Genético/métodos , Ovinos/embriologia , Superovulação , Transferência Embrionária/tendências , Desenvolvimento TecnológicoRESUMO
Nearly three years ago our research team published a review of intrinsic determinants and predictors of superovulatory responses in ewes (18th International Congress on Animal Reproduction, Tours, France; 26-30 June 2016; Theriogenology 2016;86:130-143). Heres a summary of major advances in superovulatory treatments of ewes reported over the last three years and of some most anticipated future directions. The rate of genetic improvement within a synthetic population of animals is significantly enhanced by an application of superovulation and embryo transfer. However, the sheep industry has progressed rather slowly in terms of implementing these technologies in comparison to other species although sheep have been used in many studies that paved the way to the development of modern assisted reproductive technologies (ARTs). Recently, several improvements in determining ovarian responses and non-invasively collecting/transferring embryos have been reported but some most frustrating problems associated with hormonal ovarian superstimulation (e.g., unpredictable and highly variable individual responses) remain unresolved. This warrants continued studies of both the physiological basis of and novel approaches to superovulatory treatments in sheep.(AU)