title: Ovarian superstimulation and oocyte collection in wood bison (Bison bison athabascae) during the ovulatory season.
abstract: 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.
authors.affiliation: Department of Veterinary Biomedical Sciences, University of Saskatchewan, Saskatoon, Canada.
authors.forename: J Manuel
authors.initials: JM
authors.lastname: Palomino
authors.affiliation: Faculty of Veterinary Medicine, University of Calgary, Alberta, Canada.
authors.forename: Robert B
authors.initials: RB
authors.lastname: McCorkell
authors.affiliation: Department of Large Animal Clinical Sciences, University of Saskatchewan, Saskatoon, Canada.
authors.forename: Murray R
authors.initials: MR
authors.lastname: Woodbury
authors.affiliation: Department of Veterinary Biomedical Sciences, University of Saskatchewan, Saskatoon, Canada.
authors.forename: Miriam P
authors.initials: MP
authors.lastname: Cervantes
authors.affiliation: Department of Veterinary Biomedical Sciences, University of Saskatchewan, Saskatoon, Canada. Electronic address: gpa623@mail.usask.ca.
authors.forename: Gregg P
authors.initials: GP
authors.lastname: Adams
mesh_terms: D000818:Animals; D016164:Bison / Q000502:physiology*; D005260:Female; D005640:Follicle Stimulating Hormone / Q000627:therapeutic use; D054315:Oocyte Retrieval / Q000379:methods / Q000662:veterinary*; D010060:Ovulation; D010062:Ovulation Induction / Q000379:methods / Q000662:veterinary*; D011453:Prostaglandins / Q000627:therapeutic use; D012621:Seasons
chemical_list: D011453:Prostaglandins; D005640:Follicle Stimulating Hormone
keywords: FSH; LH; Oocyte collection; Ovarian superstimulation; Wood bison; eCG