title: Unilateral ablation of follicles ≥ 4 mm leads to compensatory follicle response from the contralateral ovary in heifers.
abstract: In each of two experiments, heifers were assigned to a control group and a unilaterally ablated (UA) group (n = 6/group). In the UA group, follicles ≥ 4 mm in the left ovary were ablated by transvaginal ultrasound-guided technique at Hour 0 (8:00 AM) on the day of ovulation. Follicles in the CL-bearing right ovary remained intact. In Experiment 1, ablations continued until the next ovulation, and new follicles emerged in the right ovary in 9 of 14 (64%) waves. The number of follicles/wave (combined, 6.4 ± 0.4) did not differ between groups. In Experiment 2, follicles were counted at Hours 0, 4, 8, 12, and 24; the resistance index (RI) for blood flow in the ovarian pedicle was determined at Hours 0 and 12; and blood samples were collected every hour from Hours 0 to 12 and at Hour 24. An increase (P < 0.05) in the number of follicles in the follicle-intact ovary began at Hour 4 with complete compensation by Hour 24. Concentrations of FSH did not change between Hours 0 and 24 in the UA group but decreased (P < 0.05) in the controls by Hour 7. At Hour 12, RI to the right ovary approached being lower (P < 0.06) in the UA group than in the control group. Results indicated that unilateral ablation of follicles ≥ 4 mm led to compensatory follicle response in the follicle-intact ovary, and initially circulatory FSH concentrations were maintained and blood flow to the follicle-intact ovary increased.
authors.affiliation: Eutheria Foundation, Cross Plains, Wisconsin, USA.
authors.forename: F A
authors.initials: FA
authors.lastname: Khan
authors.forename: F L V
authors.initials: FL
authors.lastname: Pinaffi
authors.forename: M A
authors.initials: MA
authors.lastname: Beg
authors.forename: O J
authors.initials: OJ
authors.lastname: Ginther
mesh_terms: D055011:Ablation Techniques / Q000662:veterinary*; D000818:Animals; D002417:Cattle / Q000502:physiology* / Q000601:surgery; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D006080:Ovarian Follicle / Q000098:blood supply / Q000000981:diagnostic imaging / Q000254:growth & development / Q000601:surgery*; D010053:Ovary / Q000098:blood supply / Q000000981:diagnostic imaging / Q000601:surgery*; D014463:Ultrasonography
chemical_list: D005640:Follicle Stimulating Hormone