Follicle and systemic hormone interrelationships during induction of luteinized unruptured follicles with a prostaglandin inhibitor in mares.
Abstract: The objective was to determine differences in follicle and reproductive hormone characteristics in mares with ovulatory and flunixin meglumine (FM)-induced anovulatory cycles. Estrous mares were given 1500 IU hCG when the follicle was ≥ 32 mm (0 h). In Experiment 1, control mares (n = 7) were not treated further. The remaining mares (n = 11) were given 1.7 mg/kg FM i.v. twice daily, from 0 to 36 h after hCG treatment. Blood samples and ultrasonographic examinations were performed every 12 h. All control mares ovulated normally between 36 and 48 h. In contrast, eight of 11 FM mares did not ovulate, but developed luteinized unruptured follicles (LUFs). Three FM-treated mares did not develop conventional LUFs. Plasma progesterone concentrations were lower (P < 0.05) in LUF mares at 96, 120, and 216 h than in controls, whereas plasma LH concentrations were higher (P < 0.05) between 108 and 120 h in LUF mares than in controls. Plasma concentrations of PGFM and estradiol did not differ significantly between groups. In Experiment 2, the three mares that did not develop LUFs were treated, during the consecutive cycle, with the same dose of FM but with increased frequency at zero, 12, 24, 30, 36, and 48 h after hCG. One mare formed a LUF, whereas the other two did not. These two mares had lower LH concentrations than LUF or control mares in the two consecutive cycles. In conclusion, systemic treatment with FM blocked ovulation in 73% of treated mares. Mares with LUFs had lower progesterone and higher LH concentrations than control mares.
Copyright © 2011 Elsevier Inc. All rights reserved.
Publication Date: 2011-04-14 PubMed ID: 21496901DOI: 10.1016/j.theriogenology.2011.02.015Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The research article explores the effects of the prostaglandin inhibitor flunixin meglumine (FM) on follicle development and reproductive hormone levels in mares. The study found that FM treatment blocked ovulation in a majority of treated mares, inducing anovulatory cycles and resulting in a condition known as luteinized unruptured follicles (LUFs), which affects hormone concentrations.
Objective and Method
- The primary objective was to identify the variations in follicle development and reproductive hormone levels in mares undergoing ovulatory cycles and those induced to have anovulatory cycles using the drug flunixin meglumine (FM).
- Mares in estrous were given 1500 IU hCG when their follicle reached or exceeded 32 mm. In Experiment 1, control group mares received no further treatment, while the rest were given FM twice daily.
- Observations were made every 12 hours using blood samples and ultrasonographic examinations.
Findings of Experiment 1
- All mares in the control group ovulated between 36 and 48 hours after hCG treatment.
- However, eight out of eleven FM-treated mares did not ovulate but instead developed luteinized unruptured follicles (LUFs).
- The three mares that did not develop expected LUFs demonstrated different plasma progesterone and LH concentrations compared to the control group.
Experiment 2
- In the second experiment, the three mares that didn’t form LUFs in the first experiment were treated in their consecutive cycle with the same dose of FM but at higher frequencies.
- Resultantly, one mare formed a LUF, while the other two did not, and these two mares exhibited lower LH concentrations compared to LUF or control mares in the two consecutive cycles.
Conclusion
- Systemic treatment with FM prevented ovulation in over 70% of the treated mares.
- Mares with LUFs exhibited lower levels of the hormone progesterone and higher levels of the hormone LH compared to the control mares.
Cite This Article
APA
Cuervo-Arango J, Beg MA, Ginther OJ.
(2011).
Follicle and systemic hormone interrelationships during induction of luteinized unruptured follicles with a prostaglandin inhibitor in mares.
Theriogenology, 76(2), 361-373.
https://doi.org/10.1016/j.theriogenology.2011.02.015 Publication
Researcher Affiliations
- Eutheria Foundation, Cross Plains, WI, USA. juan.cuervo@uch.ceu.es
MeSH Terms
- Animals
- Anovulation
- Chorionic Gonadotropin / administration & dosage
- Clonixin / administration & dosage
- Clonixin / analogs & derivatives
- Dinoprost / analogs & derivatives
- Dinoprost / blood
- Estradiol / blood
- Female
- Hormones / physiology
- Horses / physiology
- Luteinization / drug effects
- Luteinization / physiology
- Luteinizing Hormone / blood
- Ovarian Follicle / diagnostic imaging
- Ovarian Follicle / physiology
- Ovulation
- Progesterone / blood
- Prostaglandin Antagonists / administration & dosage
- Ultrasonography
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