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Home / Equine Research Bank / Reprod Fertil Dev / Induction of haemorrhagic anovulatory follicles in mares.
Reproduction, fertility, and development2008; 20(8); 947-954; doi: 10.1071/rd08136

Induction of haemorrhagic anovulatory follicles in mares.

Abstract: A follicular wave and luteolysis were induced in mares by ablation of follicles > or =6 mm and treatment with prostaglandin F(2alpha) (PGF) on Day 10 (where ovulation = Day 0). The incidence of haemorrhagic anovulatory follicles (HAFs) in the induced waves (20%) was greater (P < 0.007) than in preceding spontaneous waves (2%). Hormone and follicle dynamics were compared between induced follicular waves that ended in ovulations (ovulating group; n = 36) v. HAFs (HAF group; n = 9). The day of the first ovulation or the beginning of HAF formation at the end of an induced wave was designated as post-treatment Day 0. The mean 13-day interval from Day 10 (PGF and ablation) to the post-treatment ovulation was normalised into Days 10 to 16, followed by Day -6 to Day 0 relative to the post-treatment ovulation. Concentrations of LH were greater (P < 0.05) in the HAF group than in the ovulating group on Days 10, 11, 12, 14, -3 and -2. The HAF group had greater (P < 0.003) LH concentrations on Day 10 of the preceding oestrous cycle with spontaneous ovulatory waves. The diameter of the largest follicle was less (P < 0.05) in the HAF group on most days between Day 13 and Day -1 and this was attributable to later (P < 0.002) emergence of the future largest follicle at 6 mm in the HAF group (Day 12.4 +/- 0.5) than in the ovulating group (Day 11.3 +/- 0.1). The results indicate that the high incidence of HAFs after PGF and ablation was associated with later follicle emergence and immediate and continuing greater LH concentration after PGF treatment, apparently augmented by an inherently high pretreatment LH concentration.
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Publication Date: 2008-11-15 PubMed ID: 19007559DOI: 10.1071/rd08136Google Scholar: Lookup
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  • Journal Article
  • Research Support
  • Non-U.S. Gov't

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The research study investigates the cause of haemorrhagic anovulatory follicles (HAFs) in mares. It concludes that an increased incidence of HAFs is associated with late follicle emergence and higher luteinising hormone (LH) levels after specific hormonal treatments and follicle ablation.

Research Methodology

  • The study was conducted on a group of mares where a follicular wave and luteolysis – the regression of the corpus luteum – were induced through follicle ablation (removal of follicles bigger than or equal to 6mm) and treatment with a hormone known as prostaglandin F(2alpha) (PGF) on Day 10 (ovulation = Day 0).
  • By comparing the hormone and follicle dynamics of mares which ovulated normally (ovulating group; n = 36) versus those who had HAFs (HAF group; n=9), the researchers could study the differences that led to the occurrence of HAFs.
  • The timeline considered for the study began with the day of the first ovulation or the beginning of HAF formation and ran until 13 days after treatment.

Findings

  • The incidence of HAFs turned out to be significantly higher (20%) in the induced waves compared to the naturally occurring ones (2%).
  • High concentrations of the Luteinising Hormone (LH) were observed on specific set of days (Days 10, 11, 12, 14, -3, -2) in the HAF group compared to the ovulating group.
  • The HAF group also exhibited higher LH concentrations on the 10th day of the preceding heat cycle.
  • Interestingly, the diameter of the largest follicle was found to be smaller in the HAF group on most days between Day 13 and Day -1, indicating a delayed emergence of the largest follicle in the HAF group.

Conclusion

  • The study concludes that the high incidence of HAFs post prostaglandin F(2alpha) and ablation treatments can be associated with a delay in the emergence of the largest follicle along with a consistent, increased presence of the LH hormone in the mares.
  • This increasing LH concentration appears to be bolstered by a naturally high pre-treatment LH concentration in the mares that developed HAFs.

Cite This Article

APA
Ginther OJ, Gastal MO, Gastal EL, Jacob JC, Beg MA. (2008). Induction of haemorrhagic anovulatory follicles in mares. Reprod Fertil Dev, 20(8), 947-954. https://doi.org/10.1071/rd08136

Publication

Reproduction, fertility, and development
ISSN: 1031-3613
NlmUniqueID: 8907465
Country: Australia
Language: English
Volume: 20
Issue: 8
Pages: 947-954

Researcher Affiliations

Ginther, O J
  • Eutheria Foundation, Cross Plains, WI 53528, USA. ginther@svm.vetmed.wisc.edu
Gastal, M O
    Gastal, E L
      Jacob, J C
        Beg, M A

          MeSH Terms

          • Ablation Techniques
          • Abortifacient Agents, Nonsteroidal / pharmacology
          • Animals
          • Anovulation / etiology
          • Anovulation / physiopathology
          • Breeding / methods
          • Dinoprost / pharmacology
          • Estradiol / blood
          • Female
          • Follicle Stimulating Hormone / blood
          • Horses / physiology
          • Luteinizing Hormone / blood
          • Luteolysis / drug effects
          • Luteolysis / physiology
          • Ovarian Follicle / cytology
          • Ovarian Follicle / drug effects
          • Ovarian Follicle / physiopathology
          • Ovulation / drug effects
          • Ovulation / physiology

          Citations

          This article has been cited 5 times.
          1. Hallman I, Karikoski N, Kareskoski M. The effects of obesity and insulin dysregulation on mare reproduction, pregnancy, and foal health: a review. Front Vet Sci 2023;10:1180622.
            doi: 10.3389/fvets.2023.1180622pubmed: 37152686google scholar: lookup
          2. Benammar A, Derisoud E, Vialard F, Palmer E, Ayoubi JM, Poulain M, Chavatte-Palmer P. The Mare: A Pertinent Model for Human Assisted Reproductive Technologies?. Animals (Basel) 2021 Aug 4;11(8).
            doi: 10.3390/ani11082304pubmed: 34438761google scholar: lookup
          3. D'Fonseca NMM, Gibson CME, Hummel I, van Doorn DA, Roelfsema E, Stout TAE, van den Broek J, de Ruijter-Villani M. Overfeeding Extends the Period of Annual Cyclicity but Increases the Risk of Early Embryonic Death in Shetland Pony Mares. Animals (Basel) 2021 Feb 1;11(2).
            doi: 10.3390/ani11020361pubmed: 33535548google scholar: lookup
          4. Pennington PM, Marshall KL, Capiro JM, Felton RG, Durrant BS. Ovulation induction in anovulatory southern white rhinoceros (Ceratotherium simum simum) without altrenogest. Conserv Physiol 2019;7(1):coz033.
            doi: 10.1093/conphys/coz033pubmed: 31249689google scholar: lookup
          5. Veiga-Lopez A, Wurst AK, Steckler TL, Ye W, Padmanabhan V. Developmental programming: postnatal estradiol amplifies ovarian follicular defects induced by fetal exposure to excess testosterone and dihydrotestosterone in sheep. Reprod Sci 2014 Apr;21(4):444-55.
            doi: 10.1177/1933719113503412pubmed: 24077439google scholar: lookup
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