Ovulation synchronization following commercial application of ultrasound-guided follicle ablation during the estrous cycle in mares.
A regimen of progesterone plus estradiol (P&E) was used as a standard for ovarian synchronization to test the efficacy and evaluate the commercial application of ultrasound-guided follicle ablation as a non-steroidal alternative for ovulation synchronization in mares. Recipient mares at a private embryo transfer facility were at unknown stages of the estrous cycle at the start of the experiment on Day 1 when they were randomly assigned to an ablation group (n=18-21 mares) or to a P&E group (n=20-21 mares). In the ablation group, mares were lightly sedated and all follicles > or = 10 mm were removed by transvaginal ultrasound-guided follicle aspiration. In the P&E group, a combination of progesterone (150 mg) plus estradiol (10mg) prepared in safflower oil was given daily (im) for 10 d. Two doses of prostaglandin F(2alpha) (PGF, 10mg/dose, im) were given 12 h apart on Day 5 in the ablation group, or a single dose on Day 10 in the P&E group. Human chorionic gonadotropin (hCG, 2500 IU/mare, im) was given at a fixed time, 6 and 10 d after PGF treatment in the ablation and P&E groups, respectively, with the expectation of a follicle > or = 30 mm at the time of treatment. In both the ablation and P&E groups, transrectal ultrasonography was done at the start of the study (Day 1) and again on the day of hCG treatment and daily thereafter to determine the presence of a CL, measure diameter of the largest follicle and detect ovulation. The mean interval from the start of the study and from PGF treatment to ovulation was shorter (P<0.0001) in the ablation group (13.7 and 9.7 d, respectively) compared to the P&E group (22.3 and 13.2 d, respectively). Following fixed-day treatment with hCG after PGF treatment, the degree of ovulation synchronization was not different (P>0.05) between the ablation and P&E groups within a 2-d (56 and 70%) or 4-d (83% and 90%) period. Although ultrasound-guided follicle ablation may not be practical in all circumstances, it excluded the conventional 10-d regimen of progesterone and estradiol and was considered an efficacious and feasible, non-steroidal alternative for ovulation synchronization in mares during the estrous cycle.
Bergfelt
D R
DR
Department of Animal Health and Biomedical Sciences, University of Wisconsin, Madison, WI 53706, USA. bergfelt@svm.vetmed.wisc.edu
Meira
C
C
Fleury
J J
JJ
Fleury
P D C
PD
Dell'Aqua
J A
JA
Adams
G P
GP
D000818:Animals; D006063:Chorionic Gonadotropin / Q000008:administration & dosage; D004958:Estradiol / Q000008:administration & dosage; D004973:Estrus Synchronization / Q000379:methods*; D005260:Female; D006736:Horses / Q000502:physiology*; D006080:Ovarian Follicle / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000601:surgery*; D010060:Ovulation / Q000187:drug effects / Q000502:physiology*; D011374:Progesterone / Q000008:administration & dosage; D011897:Random Allocation; D027724:Reproductive Techniques, Assisted / Q000662:veterinary*; D013396:Suction / Q000662:veterinary; D013997:Time Factors; D014463:Ultrasonography
D006063:Chorionic Gonadotropin; D011374:Progesterone; D004958:Estradiol