Ovulation synchronization following commercial application of ultrasound-guided follicle ablation during the estrous cycle in mares.
Abstract: 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 (P0.05) 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.
Publication Date: 2007-09-27 PubMed ID: 17904213DOI: 10.1016/j.theriogenology.2007.08.020Google Scholar: Lookup
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- Evaluation Study
- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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This research study mainly compares two different methods of ovulation synchronization in mares: a hormonal regulation process (progesterone and estradiol), and a follicle ablation process guided by ultrasound. The results show that both methods exhibit relatively equal effectiveness concerning ovulation synchronization within a 2 to 4 day period, despite the fact that the ultrasound-guided follicle ablation process significantly quickens the onset of ovulation.
Objective of the Research
- The main aim of this study was to evaluate the effectiveness of ultrasound-guided follicle ablation, a non-steroidal alternative approach, against the traditional hormonal P&E regimen for ovulation synchronization in mares.
Methodology and Experiment Setup
- The mares employed in the experiment were on unknown stages of the estrous cycle on Day 1. They were split into two groups: an ablation group (18-21 mares) and a P&E group (20-21 mares).
- In the ablation group, follicles greater or equal to 10mm were removed by transvaginal ultrasound-guided follicle aspiration.
- In the P&E group, a daily mixture of progesterone (150 mg) plus estradiol (10mg) prepared in safflower oil was administered for 10 days. Prostaglandins are used in both groups but administered differently, and human chorionic gonadotropin (hCG) was given at a fixed time, expected to coincide with the presence of a follicle of at least 30 mm.
Results and Discussion
- In the ultrasound-guided follicle ablation application, the mean interval from the start and from PGF treatment to ovulation was found to be shorter (13.7 and 9.7 days, respectively) compared to the hormonal regimen (22.3 and 13.2 days, respectively).
- The effectiveness of obtaining ovulation synchronization following the PGF treatment with hCG injection was not statistically different between the two groups over both a 2-day period (56% and 70%) and a 4-day period (83% and 90%).
Conclusion
- The study concludes that although ultrasound-guided follicle ablation might not be practical in all scenarios, it deemed an effective, non-steroidal alternative for ovulation synchronization in mares. It potentially sidesteps the traditional 10-day hormonal progesterone and estradiol scheme.
Cite This Article
APA
Bergfelt DR, Meira C, Fleury JJ, Fleury PD, Dell'Aqua JA, Adams GP.
(2007).
Ovulation synchronization following commercial application of ultrasound-guided follicle ablation during the estrous cycle in mares.
Theriogenology, 68(8), 1183-1191.
https://doi.org/10.1016/j.theriogenology.2007.08.020 Publication
Researcher Affiliations
- Department of Animal Health and Biomedical Sciences, University of Wisconsin, Madison, WI 53706, USA. bergfelt@svm.vetmed.wisc.edu
MeSH Terms
- Animals
- Chorionic Gonadotropin / administration & dosage
- Estradiol / administration & dosage
- Estrus Synchronization / methods
- Female
- Horses / physiology
- Ovarian Follicle / anatomy & histology
- Ovarian Follicle / diagnostic imaging
- Ovarian Follicle / surgery
- Ovulation / drug effects
- Ovulation / physiology
- Progesterone / administration & dosage
- Random Allocation
- Reproductive Techniques, Assisted / veterinary
- Suction / veterinary
- Time Factors
- Ultrasonography
Citations
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