title: Superstimulatory response and oocyte collection in North American bison during the non-breeding season.
abstract: 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 2500IU of eCG given on Day 0, or (ii) two subcutaneous doses of 200mg of FSH given on Days 0 and 2. On Day 4, 200mg 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 ≥5mm (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.
authors.affiliation: Department of Veterinary Biomedical Sciences, University of Saskatchewan, Saskatoon, SK, Canada. jmanuel.palomino@usask.ca
authors.forename: J Manuel
authors.initials: JM
authors.lastname: Palomino
authors.forename: Robert B
authors.initials: RB
authors.lastname: McCorkell
authors.forename: Murray R
authors.initials: MR
authors.lastname: Woodbury
authors.forename: Miriam P
authors.initials: MP
authors.lastname: Cervantes
authors.forename: Gregg P
authors.initials: GP
authors.lastname: Adams
mesh_terms: D000818:Animals; D016164:Bison / Q000502:physiology*; D018592:Cross-Over Studies; D004973:Estrus Synchronization / Q000502:physiology*; D005260:Female; D005640:Follicle Stimulating Hormone / Q000008:administration & dosage / Q000494:pharmacology*; D006064:Gonadotropins, Equine / Q000008:administration & dosage / Q000494:pharmacology*; D054315:Oocyte Retrieval / Q000379:methods / Q000662:veterinary; D009865:Oocytes / Q000502:physiology*; D006080:Ovarian Follicle / Q000502:physiology*; D010062:Ovulation Induction / Q000379:methods / Q000662:veterinary*; D011897:Random Allocation
chemical_list: D006064:Gonadotropins, Equine; D005640:Follicle Stimulating Hormone
keywords: FSH; LH; Oocyte collection; Ovarian superstimulation; Wood bison; eCG