Ultrasonic anatomy of equine ovaries.
Abstract: A linear-array ultrasound scanner with a 5-MHz transducer was evaluated for studying follicular and luteal status in mares, and the ultrasonic properties of equine ovaries were characterized. Follicular diameters were estimated in vivo and after removing and slicing six ovaries. Correlation coefficients between the two kinds of determinations were 0.91 for number of follicles >/=2 mm in diameter and 0.95 for diameter of largest follicle. The ovaries of five mares were examined daily until all mares had been examined from three days before an ovulation to three days after the next ovulation. There was a significant difference among days for diameter of largest follicle and second largest follicle and for number of follicles 2-5 mm, 16-20 mm, and >20 mm. Differences seemed to be caused by the presence of many 2- to 5-mm follicles during early diestrus, initiation of growth of large follicles at mid-cycle, selective accelerated growth of an ovulatory follicle beginning five days before ovulation, and regression of large nonovulatory follicles a few days before ovulation. In one of the five mares, the corpus luteum was identified throughout the interovulatory interval, and the corresponding corpus albicans was identified for three days after the second ovulation. In the other four mares, the corpus luteum was last identified an average of 16 days after ovulation or five days before the next ovulation. In a blind study, the location of the corpus luteum (left or right ovary) as determined by ultrasonography agreed with a previous determination of side of ovulation by palpation in 88% of 40 mares on days 0-14. In the remaining 12% and in all of 12 estrous mares, the location was recorded as uncertain. The ultrasound instrument was judged effective for monitoring and evaluating follicles and corpora lutea.
Publication Date: 1984-03-01 PubMed ID: 16725897DOI: 10.1016/0093-691x(84)90409-6Google Scholar: Lookup
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- Journal Article
Summary
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This research explores the effectiveness of using a linear-array ultrasound scanner to study the follicular and luteal status of horse ovaries, revealing a high correlation with traditional methods. The scanner reliably identified follicular diameters and was able to track changes across different phases of the ovulation cycle.
Research Method
- The researchers used a linear-array ultrasound scanner with a 5-MHz transducer to examine the anatomy of horse ovaries. This involved analyzing follicular diameters both in vivo and ex vivo by removing and slicing the ovaries.
- The ovaries of five horses were examined daily, before, during, and after ovulation. The researchers thus observed the changes in follicular size across different stages of the ovulation cycle.
- In addition, they also identified and observed the corpus luteum, a structure involved in ovulation and the menstrual cycle, throughout the interovulatory interval.
- In a blind study, the researchers compared the location of the corpus luteum as determined by ultrasound results with previous determinations made by palpation.
Research Findings
- The results indicated a high level of correlation between ultrasound estimates and physical measurements. This was seen in high correlation coefficients for the number of follicles larger than 2 mm in diameter and for the diameter of the largest follicle.
- Significant differences were observed in the diameter of the largest follicle, the second largest follicle, and the number of follicles in various size ranges across different days, indicating important changes throughout the ovulation cycle.
- The findings reveal the pattern of growth of follicles throughout the ovulation cycle, specifically showing accelerated growth of a single follicle — the ovulatory follicle — beginning five days prior to ovulation.
- Identification of the corpus luteum varied among the mares. In one, it was identified throughout the interval between two ovulations, while in others it was last identified an average of 16 days after ovulation or five days before the next one.
- In the blind study, agreement between the ultrasound-determined location of the corpus luteum and previous palpation results was found in 88% of cases.
Conclusion
- The study concludes that the linear-array ultrasound scanner is an effective tool for evaluating the follicular and luteal status in horse ovaries, including monitoring follicular growth and observing the corpus luteum.
Cite This Article
APA
Ginther OJ, Pierson RA.
(1984).
Ultrasonic anatomy of equine ovaries.
Theriogenology, 21(3), 471-483.
https://doi.org/10.1016/0093-691x(84)90409-6 Publication
Researcher Affiliations
- Department of Veterinary Science University of Wisconsin Madison, WI 53706 USA.
Grant Funding
- 11489 / Canadian Institutes of Health Research
Citations
This article has been cited 2 times.- Segabinazzi LGTM, Gilbert RO, Ambrosia RL, Bergfelt DR, Samper JC, Peterson EW, French HM. Structural and Functional Dynamics of the Ovary and Uterus during the Estrous Cycle in Donkeys in the Eastern Caribbean. Animals (Basel) 2022 Dec 24;13(1).
- Montano GA, Clough P, Schmitt T, Davis M, O'Brien JK, Steinman K, Robeck T. Follicular and Hormonal Changes after Estrous Synchronization in Bottlenose Dolphins. Reprod Fertil 2022 Sep 1;3(3):238-54.
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