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Home / Equine Research Bank / Acta Vet Scand / Acceleration and timing of fertile ovulation in cyclic mares...
Acta veterinaria Scandinavica1995; 36(4); 393-400; doi: 10.1186/BF03547654

Acceleration and timing of fertile ovulation in cyclic mares with a deslorelin implant.

Abstract: In a blinded trial, the effectiveness and safety of 2.2 mg of the GnRH analog deslorelin acetate, administered in a short-term implant (STI) to normally cycling mares in estrus with a dominant ovarian follicle of 30 mm in diameter or larger, were evaluated, using a placebo implant as a negative control. A total of 39 mares received treatments at admittance with pre-randomized implants containing either 2.2 mg or 0 mg deslorelin. Mares were teased daily and examined rectally with ultrasound at 24 h intervals to determine time to ovulation and duration of estrus. The number of breedings and the pregnancy rate at 18 (+/- 3) and 38 (+/- 3) days were recorded, as were systemic side effects and local reactions at the implantation sites. Pregnancies resulting from breedings during the treatment estrus and/or from breedings during the next estrus were followed and the early and late pregnancy loss rate, the number of pregnancies going to term and of live-born foals was recorded. Mean follicle diameter at treatment was not significantly different between the deslorelin and placebo treatment group with 41.6 mm and 40.8 mm, respectively. Treatment with deslorelin STI reduced the time interval to ovulation significantly from 69.5 +/- 25.48 h to 42.7 +/- 12.35 h (p < 0.001). The percentage of mares having ovulated within 48 h rose from 26.3% to 95.0%, respectively, for placebo and deslorelin STI (p 0.005), and in 70.0% and 66.7% of these once or twice bred mares did pregnancies go to term and live foals were born. En potent GnRH analog, deslorelinacetat, i form av ett implantat med korttidsfrisättning har provats i olika koncentrationer för att utvärdera möjligheten att ersätta HCG. Dosen 2.2 mg deslorelin per implantat befanns optimal. I ett kliniskt försök under 1992 behandlades 20 ston med deslorelin och 19 ston med placeboimplantat. Stona kontrollerades dagligen på förekommande brunsttecken och undersöktes rektalt och med ultraljud var 24 timme. Ston med folliklar ≥30 mm togs in i försöket. Implantatet sattes in subcutant på halsens vänstra sida med en 3 mm kanyl. Stona seminerades med färsk, kyld eller fryst sperma. Dräktighetsdiagnos ställdes via ultraljud på dag 18 och 38. Tidsintervallet mellan behandling och ovulation skilde signifikant mellan grupperna med 42,7 tim och respektive 69,2 tim för deslorelinbehandlade ston resp placebobehandlade. 95% behandlade ston ovulerade inom 48 tim mot 26,32% av de obehandlade. Brunstens längd förkortades signifikant (4,55 dagar mot 5,37) och därmed antalet semineringar / bctäckningstillfällen. Ingen skillnad i dräktighetsprocent samt fölningsprocent förelag. Inga eller mycket lindriga bieffekter i form av svullnad på halsen efter implantatet noterades.
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Publication Date: 1995-01-01 PubMed ID: 8669367PubMed Central: PMC8095403DOI: 10.1186/BF03547654Google Scholar: Lookup
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  • Clinical Trial
  • Journal Article
  • Randomized Controlled Trial
  • Research Support
  • Non-U.S. Gov't

Summary

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The research paper discusses a controlled experiment examining the effectiveness and safety of using a deslorelin acetate implant on mares in estrus with a large ovarian follicle, as compared to those with a placebo implant. The deslorelin implant was found to significantly reduce the time interval to ovulation and the overall duration of estrus, without significant side effects.

Methodology

  • The trial involved 39 randomly selected mares, who were each given either a 2.2mg deslorelin implant or a placebo implant.
  • Mares were teased daily and examined rectally with an ultrasound every 24 hours to determine the time of ovulation and the overall duration of their estrous cycle.
  • The number of breedings required and the pregnancy rate at varying timelines were noted, alongside any systemic side effects or local reactions at the implantation sites.
  • Pregnancies resulting from breedings during the treatment estrus and from the succeeding estrus cycle were tracked, recording early and late pregnancy loss rates, the number of pregnancies going to term and the total number of live-born foals.

Findings

  • The diameter of the follicle at the time of treatment did not significantly differ between the deslorelin and placebo groups, with averages of about 41.6mm and 40.8mm respectively.
  • However, the use of the deslorelin implant significantly reduced the interval to ovulation from approximately 69.5 hours to 42.7 hours.
  • Thus, the percentage of mares ovulating within 48 hours rose dramatically, from 26.3% in the placebo group to 95% in the deslorelin group.
  • As a result, the overall duration of estrus was reduced, as was the number of animals needing more than one breeding attempt.
  • Pregnancy rates were satisfactory and similar for both groups.
  • A significant majority of the treatments led to term pregnancies and live foals being born.

Conclusion

  • Overall, the deslorelin implant was found to be an effective and safe method of accelerating the timing of ovulation in mares, and reducing the number of breeding attempts required.
  • No significant side effects were noted, making this a potentially useful treatment for managing mare reproduction.

Cite This Article

APA
Gånheim A, Gånheim A, Jöchle W. (1995). Acceleration and timing of fertile ovulation in cyclic mares with a deslorelin implant. Acta Vet Scand, 36(4), 393-400. https://doi.org/10.1186/BF03547654

Publication

Acta veterinaria Scandinavica
ISSN: 0044-605X
NlmUniqueID: 0370400
Country: England
Language: English
Volume: 36
Issue: 4
Pages: 393-400

Researcher Affiliations

Gånheim, A
  • Swedish National Stud, Veterinary Services, Flyinge, Sweden.
Gånheim, A
    Jöchle, W

      MeSH Terms

      • Animals
      • Double-Blind Method
      • Drug Implants
      • Enzyme Inhibitors / administration & dosage
      • Estrus / physiology
      • Estrus Detection / veterinary
      • Female
      • Gonadotropin-Releasing Hormone / administration & dosage
      • Gonadotropin-Releasing Hormone / analogs & derivatives
      • Horses / physiology
      • Ovulation / drug effects
      • Pregnancy
      • Time Factors
      • Triptorelin Pamoate / analogs & derivatives

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