title: Persistence and recovery of regressing 3-mm ovarian follicles in heifers.
abstract: The persistence and outcome of 3-mm follicles before the emergence of follicular wave 1 were studied every 6 hours in 15 heifers beginning on Day 14 (Day 0 = ovulation). A mean of 9.1 ± 1.3 persistent 3-mm follicles (P3Fs) per heifer was detected with persistence for 3.5 ± 0.1 days. The P3Fs either regressed continuously and remained in the 3-mm range (3.0-3.9 mm) or regressed but with a transient increase in diameter during regression. Some (43%) P3Fs were rescued to become growing follicles in wave 1. The number of follicles that became part of wave 1 was less (P < 0.0001) for follicles that originated from a P3F (4.2 ± 1.0 P3Fs) than for follicles that did not originate from a P3F (11.9 ± 1.6 follicles). The day of rescue of wave 1 follicles from a P3F (Day -1.1 ± 0.6) was earlier (P < 0.001) than for emergence of follicles at 3 mm that did not originate from a P3F (Day -0.5 ± 0.5). A cluster of 5.1 ± 0.6 P3Fs was identified in 10 of 15 heifers by the synchronized peaks of transient diameter increases at the 6-hour interval corresponding to Day -4.0 ± 0.3. Concentrations of FSH oscillated at 12-hour intervals with a peak (P < 0.05) 6 hours before and 6 hours after the beginning of a transient diameter increase during a P3F. Concentration of FSH was greater (P < 0.02) in heifers with a high number (11-18) of P3Fs per heifer (0.27 ± 0.02 ng/mL) than with a low number (2-9) per heifer (0.17 ± 0.008 ng/mL). Results supported the novel hypothesis that 3-mm follicles may persist for two or more days and may be rescued to become growing follicles of wave 1.
authors.affiliation: Eutheria Foundation, Cross Plains, Wisconsin, USA; Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, USA. Electronic address: ginther@vetmed.wisc.edu.
authors.forename: O J
authors.initials: OJ
authors.lastname: Ginther
authors.affiliation: Eutheria Foundation, Cross Plains, Wisconsin, USA; Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, USA.
authors.forename: M A R
authors.initials: MA
authors.lastname: Siddiqui
authors.affiliation: Eutheria Foundation, Cross Plains, Wisconsin, USA.
authors.forename: J M
authors.initials: JM
authors.lastname: Baldrighi
authors.affiliation: Eutheria Foundation, Cross Plains, Wisconsin, USA; Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, USA.
authors.forename: C A
authors.initials: CA
authors.lastname: Wolf
mesh_terms: D000818:Animals; D002417:Cattle / Q000502:physiology*; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D006080:Ovarian Follicle / Q000502:physiology*; D010060:Ovulation / Q000502:physiology
chemical_list: D005640:Follicle Stimulating Hormone
keywords: FSH; Follicle persistence; Minor follicular wave; Rescue of regressing follicle; Transient diameter increase