Examinando por Autor "McCorkell, Robert B."
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Ítem Acceso Abierto Ovarian superstimulation and oocyte collection in wood bison (Bison bison athabascae) during the ovulatory season(Elsevier, 2014) Palomino Cano, Jesús Manuel; McCorkell, Robert B.; Woodbury, Murray R.; Cervantes, Miriam P.; Adams, Gregg P.The objective of the study was to establish an effective ovarian superstimulatory protocol and subsequently obtain oocytes from bison by transvaginal ultrasound-guided follicular aspiration. Two experiments involving 22 wood bison were done during the breeding season (September to December). In experiment 1, the bison were given a luteolytic dose of prostaglandin (Day 0) and underwent follicular ablation (Day 8) to induce ovarian synchrony. Synchronized bison were then assigned randomly to two groups (n = 11 per group) and given either 200 mg FSH diluted in saline sc, or 200 mg FSH diluted in a proprietary slow-release formulation (SRF) im on Days 9 and 11. Prostaglandin was given to both groups on Day 11 followed by 25 mg LH on Day 13. Oocytes were collected by transvaginal ultrasound-guided aspiration of follicles ≥5 mm on Day 14. In experiment 2, bison were synchronized as in experiment 1 and assigned randomly to one of two groups (n = 11 per group) and given either a single dose of 2500 IU eCG im on Day 9, or 200 mg FSH sc on Days 9 and 11. Prostaglandin was given to both groups on Day 11, and LH (25 mg) was given on Day 13. Oocyte collection was done as described in experiment 1. Cumulus-oocyte-complexes (COC) were classified according to morphologic characteristics. In experiment 1, more follicles ≥5 mm were detected on Day 14 in bison treated with FSH versus eCG (12.2 ± 1.73 vs. 5.8 ± 0.52; P < 0.05), and more COC were collected from FSH-treated animals (7.2 ± 1.41 vs. 3.4 ± 0.62; P < 0.05). In experiment 2, the FSH-saline and FSH-SRF groups had a similar number (mean value ± standard error of the mean) of follicles ≥5 mm on Day 14 (12.4 ± 1.49 vs. 13.8 ± 1.24, respectively) and a similar number of COC were collected (6.5 ± 1.13 vs. 6.3 ± 0.96, respectively). The proportion of COC collected per follicle aspirated and the percentage of compact, expanded, and denuded oocytes did not differ between groups in either experiment 1 or 2. In summary, a two-dose regimen of FSH diluted in saline and given sc or in a SRF and given im induced a similar ovarian response in wood bison, whereas a single dose of eCG resulted in a significantly lower ovarian response. Overall, COC were collected from 55% of follicles after transvaginal, ultrasound-guided needle aspiration in wood bison.Ítem Solo Metadatos Ovarian synchronisation in wood bison (Bison bison athabascae) during the anovulatory season(Commonwealth Scientific and Industrial Research Organisation, 2013) Palomino Cano, Jesús Manuel; McCorkell, Robert B.; Woodbury, Murray R.; Adams, Gregg P.Two experiments were performed in wood bison during the anovulatory season to establish an effective protocol for ovarian synchronisation. In an untreated control phase, bison cows (n = 19) were examined daily to establish the interval to new follicular wave emergence (4.9 ± 0.7 days) for the purposes of comparison with the experimental treatments. In Experiment 1, bison were treated by transvaginal ultrasound-guided follicular ablation (n = 9) or with 2 mg, i.m., 17β-oestradiol (n = 10). In Experiment 2, bison were treated by follicular ablation (n = 9) or with 2 mg, i.m., 17β-oestradiol +100 mg, i.m., progesterone (n = 10). In Experiment 1, the interval to new wave emergence for control, follicular ablation and 17β-oestradiol-treated groups was 4.9 ± 0.7, 1.1 ± 0.1 and 3.1 ± 0.4 days, respectively (P < 0.05). The degree of synchrony was 2.4 ± 0.4, 0.2 ± 0.1 and 0.8 ± 0.2 days, respectively (P < 0.05). In Experiment 2, the interval to new wave emergence for control, follicular ablation and 17β-oestradiol + progesterone-treated groups was 4.9 ± 0.7, 1.2 ± 0.2 and 3.3 ± 0.3 days, respectively (P < 0.05), and the degree of synchrony was 2.4 ± 0.4, 0.2 ± 0.1, and 0.8 ± 0.2 days, respectively (P < 0.05). The degree of synchrony did not differ between ablation and hormone treatment groups in either experiment, but was greater in treatment groups than in the untreated control phase. Both follicular ablation and hormone treatment shortened and decreased the variability in the interval to follicular wave emergence in bison, but wave emergence occurred earlier after follicular ablation.Ítem Acceso Abierto Superovulation in wood bison (Bison bison athabascae) during the ovulatory and anovulatory seasons: effects of progesterone, treatment protocol and gonadotropin preparations for the induction of ovulation(Elsevier, 2016) Palomino Cano, Jesús Manuel; Cervantes, Miriam P.; McCorkell, Robert B.; Mapletoft, Reuben J.; Adams Gregg P.Experiments were done to determine the ovarian response and embryo production following superstimulation of wood bison. In Experiment 1 (Anovulatory season), the efficacy of pLH vs. hCG for inducing ovulation was compared in wood bison superstimulated with a single dose of pFSH in 0.5% hyaluronan and the effect of exogenous progesterone (PRID) on superovulatory response and embryo quality was examined. In Experiment 2 (Ovulatory season), the efficacy of pLH vs. hCG for the induction of ovulation was compared in wood bison superstimulated with pFSH in a single intramuscular dose vs. a two-dose regimen 48 h apart (split dose) in 0.5% hyaluronan. In Experiment 1, the number of CL was greater (P < 0.05) in bison treated with hCG than pLH (6.6 ± 1.8 vs. 2.8 ± 0.8) and in those that were not given PRID (6.0 ± 1.5 vs. 2.7 ± 1.0). There was no effect of progesterone treatment on embryo quality. In Experiment 2, the number of CL was greater (P < 0.05) in bison treated with hCG than with pLH (6.3 ± 0.8 vs. 3.8 ± 1.2) and in bison superstimulated with split dose vs. single dose of FSH (7.1 ± 0.9 vs. 3.0 ± 0.8). The number of ova/embryos and freezable embryos did not differ among groups in either experiment. In conclusion, hCG induced a greater ovulatory response than pLH in both seasons. Two doses of FSH induced the greatest superovulatory response during the ovulatory season. Exogenous progesterone did not improve embryo quality during the anovulatory season.Ítem Acceso Abierto Superstimulatory response and oocyte collection in North American bison during the non-breeding season(Elsevier, 2013) Palomino Cano, Jesús Manuel; McCorkell, Robert B.; Woodbury, Murray R.; Cervantes, Miriam P.; Adams, Gregg P.A 2 × 2 design was used to compare the ovarian response and oocyte collection characteristics in bison given a superstimulatory dose of eCG or FSH, with or without a follow-up dose of LH. Follicular wave emergence was synchronized by follicle ablation (Day −1) and bison were assigned randomly to two superstimulatory treatment groups (n = 10 per group): (i) a single intramuscular dose of 2500 IU of eCG given on Day 0, or (ii) two subcutaneous doses of 200 mg of FSH given on Days 0 and 2. On Day 4, 200 mg of LH was given intramuscularly in 5 bison in each superstimulatory treatment group. The study was done in two replicates (n = 20 per replicate) involving a crossover design so that each animal was given the opposite superstimulatory treatment (eCG or FSH) during successive replicates. Cumulus-oocyte complexes (COC) were collected by transvaginal ultrasound-guided follicle aspiration, and were classified according to morphologic attributes as compact, expanded, or denuded. Superstimulatory treatment with FSH (vs. eCG) resulted in the development of more follicles ≥5 mm (14.2 ± 1.41 vs. 8.2 ± 0.67; P < 0.05; mean ± SEM), and more follicles aspirated (12.4 ± 1.3 vs. 6.3 ± 0.6; P < 0.04). Follow-up treatment with LH (vs. no LH) resulted in a greater proportion of expanded COC (37% vs. 15%; P < 0.05), and a tendency for a higher COC collection rate (61% vs. 54%; P = 0.08). In summary, superstimulation with FSH (vs. eCG) resulted in twice as many follicles available for aspiration and nearly twice as many COC collected in bison during the anovulatory season, and follow-up treatment with LH increased the proportion of expanded COC collected.