title: FSH withdrawal improves developmental competence of oocytes in the bovine model.
abstract: Combinations of genetic, environmental, and management factors are suspected to explain the loss in fertility observed for over 20 years in dairy cows. In some cases, IVF is used. When compared with in vivo embryo production, IVF resulted in low success rates until the FSH coasting process (FSH starvation after superstimulation) was introduced in 2002. Increased competence associated with FSH withdrawal of aspirated oocyte for in vitro maturation and IVF has not been optimized nor explained yet. The goal here was to determine and characterize the optimal oocyte competence acquisition window during the coasting period by determining blastocyst rates and follicular cohort development. Commercial milking cycling cows (n=6) were stimulated with 3 days of FSH (6×40 mg NIH Folltropin-V given at 12 h intervals) followed by a coasting period of 20, 44, 68, or 92 h. Each animal was exposed to the four conditions and served as its own control. At the scheduled time, transvaginal aspirations of immature oocytes were performed followed by IVF of half the oocytes. The outcomes were as follows: i) FSH coasting was optimal at a defined period: between 44 and 68 h of coasting; ii) The best estimated coasting duration was ∼54±7 h; iii) Under these conditions, the best statistical blastocyst rate estimation was ∼70%; iv) Between 44 and 68 h of coasting, follicle size group proportions were similar; v) Follicle diameter was not linearly associated with competence. In conclusion, coasting duration is critical to harvest the oocytes at the right moment of follicular differentiation.
authors.affiliation: Département des Sciences Animales, Pavillon INAF, Centre de Recherche en Biologie de la Reproduction, Université Laval, Québec, Quebec, Canada.
authors.forename: Anne-Laure
authors.initials: AL
authors.lastname: Nivet
authors.forename: Audrey
authors.initials: A
authors.lastname: Bunel
authors.forename: Rémi
authors.initials: R
authors.lastname: Labrecque
authors.forename: Josée
authors.initials: J
authors.lastname: Belanger
authors.forename: Christian
authors.initials: C
authors.lastname: Vigneault
authors.forename: Patrick
authors.initials: P
authors.lastname: Blondin
authors.forename: Marc-André
authors.initials: MA
authors.lastname: Sirard
mesh_terms: D000818:Animals; D002417:Cattle; D002478:Cells, Cultured; D004334:Drug Administration Schedule; D046149:Embryo Culture Techniques / Q000379:methods / Q000662:veterinary; D047108:Embryonic Development / Q000187:drug effects* / Q000502:physiology; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods; D005640:Follicle Stimulating Hormone / Q000008:administration & dosage / Q000494:pharmacology*; D023421:Models, Animal; D008962:Models, Theoretical; D009865:Oocytes / Q000187:drug effects* / Q000502:physiology; D009866:Oogenesis / Q000187:drug effects / Q000502:physiology; D010062:Ovulation Induction / Q000662:veterinary; D011247:Pregnancy; D011336:Probability; D013997:Time Factors; D028761:Withholding Treatment
chemical_list: D005640:Follicle Stimulating Hormone