Puberty in the female pony: reproductive behavior, ovulation, and plasma gonadotropin concentrations.
Abstract: Reproductive behavior and gonadotropin concentrations were studied in 14 female ponies during the period from 10 to 21 months of age (February 1978 to January 1979). Nine fillies were born during April of 1977 (spring-born) and five were born during the summer and fall of 1977 (late-born). Three of the spring-born fillies had been ovariectomized (OVX) at 4 months of age. All intact spring-born fillies ovulated during late spring when they were 12–15 months old. Two of five late-born fillies did not ovulate, and there tended to be fewer ovulations and a shorter breeding season in late-born than in spring-born fillies. These results indicated that the onset of puberty and reproductive activity during the first ovulatory season was affected by season of birth. In the two late-born fillies that did not ovulate (based on the absence of corpora albicantia), several LH and progesterone surges occurred which were similar to the surges associated with ovulation in the remaining fillies. The breeding season appeared to be shorter in fillies than had been reported previously for adult mares, due primarily to an earlier termination of reproductive activity. Changes in plasma concentrations of FSH and LH preceding, during, and immediately after the first ovulatory season were similar to what has been reported for adult ponies. Estrous behavior accompanied 91% of the ovulations and two of three OVX fillies showed estrous behavior. Plasma FSH and LH concentrations followed a seasonal pattern in the OVX fillies, with the highest levels occurring during the summer.
Publication Date: 1981-06-01 PubMed ID: 6791718DOI: 10.1095/biolreprod24.5.977Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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This research article discusses a study on reproductive behavior and gonadotropin concentrations in teenage female ponies, exploring the impacts of factors such as season of birth and ovulation patterns.
Research Objective
- The study aims to analyze the reproductive behavior, ovulation, and plasma gonadotropin concentration in 14 female ponies from the age of 10 to 21 months. The research investigates the effects of season of birth and ovulation activity during the first ovulatory season on the onset of puberty and reproductive activity in female ponies.
Research Methodology
- The subjects of the study were 14 female ponies, divided based on their births either in spring (April) or late in the year (summer and fall). Three spring-born fillies had their ovaries removed at four months of age.
- The research monitored the ovulation activity, specifically checking for the presence of corpora albicantia, an ovulation indicator. The surges in luteinizing hormone (LH) and progesterone, behavior associated with estrus (reproductive cycle phase), and plasma follicle-stimulating hormone (FSH) and LH concentrations were all observed.
Key Findings
- All spring-born fillies ovulated when they were 12–15 months old, during late spring. Late-born fillies had fewer ovulations and a shorter breeding season.
- The onset of puberty and first ovulatory season’s reproductive activity seemed to be influenced by the birth season. Notably, two of the late-born fillies didn’t ovulate but exhibited LH and progesterone surges, like those noted in ovulating fillies.
- The study found that the first breeding season in fillies is shorter than adult mares, primarily due to an earlier cessation of their reproductive activity.
- In conjunction with the first ovulatory season, changes in the plasma FSH and LH concentrations were similar to those in adult ponies. Furthermore, estrous behavior accompanied 91% of the ovulations. Two of the three fillies, whose ovaries had been removed, showed estrous behavior as well.
- Plasma FSH and LH concentrations in the fillies without ovaries followed a seasonal pattern, with peak levels during summer.
Cite This Article
APA
Wesson JA, Ginther OJ.
(1981).
Puberty in the female pony: reproductive behavior, ovulation, and plasma gonadotropin concentrations.
Biol Reprod, 24(5), 977-986.
https://doi.org/10.1095/biolreprod24.5.977 Publication
Researcher Affiliations
MeSH Terms
- Animals
- Female
- Follicle Stimulating Hormone / blood
- Horses / physiology
- Luteinizing Hormone / blood
- Ovulation
- Reproduction
- Seasons
- Sexual Maturation
Citations
This article has been cited 3 times.- Devick IF, Leise BS, McCue PM, Rao S, Hendrickson DA. Ovarian histopathology, pre- and post-operative endocrinological analysis and behavior alterations in 27 mares undergoing bilateral standing laparoscopic ovariectomy. Can Vet J 2020 Feb;61(2):181-186.
- Geiger M, Sánchez-Villagra MR. Similar rates of morphological evolution in domesticated and wild pigs and dogs. Front Zool 2018;15:23.
- Ono M, Akuzawa H, Nambo Y, Hirano Y, Kimura J, Takemoto S, Nakamura S, Yokota H, Himeno R, Higuchi T, Ohtaki T, Tsumagari S. Analysis of the equine ovarian structure during the first twelve months of life by three-dimensional internal structure microscopy. J Vet Med Sci 2016 Jan;77(12):1599-603.
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