Emergence and selection of the dominant follicle and gonadotropin dynamics in postpartum lactating versus non-postpartum cycling mares.
Abstract: Among female livestock, the mare has the shortest interval from parturition to first ovulation. Due to the scarcity of research on postpartum mares, little progress has been made on the characterization of the resumption of ovarian cyclicity after parturition. This study compared follicular and gonadotropin dynamics during follicle emergence and deviation in postpartum lactating (PP Lactating) versus non-postpartum cycling (N-PP Cycling) mares. On the day of parturition, every PP Lactating mare was paired with a N-PP Cycling mare. Comparisons were made by considering the partum-ovulation interval and the postpartum interovulatory interval for the PP Lactating mares, and two interovulatory intervals for the N-PP Cycling mares. The results presented herein demonstrate that during the postpartum period, lactating mares have some similarities in follicular and hormonal profiles around emergence and deviation when compared with non-postpartum cycling mares. However, some peculiar and important characteristics were noticed during the postpartum period in lactating mares: (1) The emergence of the DF occurs around the day of parturition; (2) follicle deviation in the ovulatory wave occurs earlier during the foal heat than in other intervals; (3) lower FSH and LH systemic concentrations were not detrimental enough to prevent the rapid resumption of ovarian activity just after parturition; and (4) the association between parturition and season can have an additional and confounding effect during postpartum ovarian activity in mares. The novel findings of this study provide better knowledge of the resumption of ovarian activity after parturition and may help provide insight into the reproductive management of this species.
Copyright © 2022 Society for Biology of Reproduction & the Institute of Animal Reproduction and Food Research of Polish Academy of Sciences in Olsztyn. Published by Elsevier B.V. All rights reserved.
Publication Date: 2022-05-10 PubMed ID: 35561513DOI: 10.1016/j.repbio.2022.100618Google Scholar: Lookup
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- Journal Article
Summary
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The study investigates the dynamics of follicle emergence, deviation and gonadotropin in postpartum lactating mares as compared to non-postpartum cycling mares. It uncovers unique hormonal and follicular activities contributing to the rapid resumption of ovarian activity in mares post-parturition.
Research Design
- The researchers paired each postpartum lactating (PP Lactating) mare with a non-postpartum cycling (N-PP Cycling) mare and observed them from the day of parturition.
- The research focused on the comparison of follicular and gonadotropin dynamics during follicle emergence and deviation in these two groups.
- The comparisons were based on the partum-ovulation interval and the postpartum interovulatory interval for the postpartum lactating mares, and two interovulatory intervals for the non-postpartum cycling mares.
Findings
- The study revealed that the postpartum period, in lactating mares, exhibits some similarities in follicular and hormonal profiles around emergence and deviation when compared with non-postpartum cycling mares.
- However, during the postpartum period in lactating mares there are unique characteristics. The first is the emergence of the dominant follicle (DF) around the day of parturition.
- Follicle deviation in the ovulatory wave occurs earlier during the ‘foal heat’ (first heat post-foaling) than in other periods.
- Lower Follicle Stimulating Hormone (FSH) and Luteinizing Hormone (LH) systemic concentrations did not prevent quick resumption of ovarian activity after parturition. This indicates that these hormonal changes are not detrimental to the ovarian cycle.
- The association between parturition and season could also influence postpartum ovarian activity in mares.
Conclusions and Implications
- The research offers new insights into the resumption of ovarian activity in mares after parturition, noting that certain follicular and hormonal characteristics can stimulate quick return to ovarian cyclicity.
- These findings could potentially facilitate greater understanding in the reproductive management of equine species, especially concerning the optimal breeding times and intervals post-parturition.
Cite This Article
APA
Pastorello M, Gastal MO, Godoi DB, Gastal EL.
(2022).
Emergence and selection of the dominant follicle and gonadotropin dynamics in postpartum lactating versus non-postpartum cycling mares.
Reprod Biol, 22(2), 100618.
https://doi.org/10.1016/j.repbio.2022.100618 Publication
Researcher Affiliations
- Animal Science, School of Agricultural Sciences, Southern Illinois University, Carbondale, IL, USA.
- Animal Science, School of Agricultural Sciences, Southern Illinois University, Carbondale, IL, USA; Department of Animal Science, Federal University of Viçosa, Viçosa, MG, Brazil.
- Department of Veterinary, Federal University of Viçosa, Viçosa, MG, Brazil.
- Animal Science, School of Agricultural Sciences, Southern Illinois University, Carbondale, IL, USA; Department of Veterinary, Federal University of Viçosa, Viçosa, MG, Brazil. Electronic address: egastal@siu.edu.
MeSH Terms
- Animals
- Female
- Follicle Stimulating Hormone
- Gonadotropins
- Horses
- Humans
- Lactation
- Ovarian Follicle
- Ovulation
- Postpartum Period
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).
- Cardona-García M, Jiménez-Escobar C, Ferrer MS, Maldonado-Estrada JG. Follicular Dynamics and Pregnancy Rates during Foal Heat in Colombian Paso Fino Mares Bred under Permanent Grazing. Animals (Basel) 2024 Feb 29;14(5).
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