Vet Med - Czech, 2012, 57(1):36-41 | DOI: 10.17221/4970-VETMED

Growth of the dominant follicle and endometrial folding after administration of hCG in mares during oestrus

R. Dolezel1, K. Ruzickova2, G. Maceckova3
1 University of Veterinary and Pharmaceutical Sciences, Brno, Czech Republic
2 Private Veterinary Practices, Velke Nemcice, Czech Republic
3 Baby Horse Center, Beroun, Czech Republic

The purpose of the trial was evaluation of follicular growth and endometrial folding in mares after human chorionic gonadotropin (hCG) treatment in comparison with untreated mares during oestrus. In addition, the influence of follicle size at the time of hCG treatment on these parameters was evaluated. HCG (3000 IU) was administered intravenously in 17 mares bearing dominant follicles 35-40 mm in diameter (Group A) and in 13 mares with larger follicles (Group B). Ten mares with follicles ≥ 35 mm were untreated (Group C). Ultrasonographical examination of the mares continued in 6 h intervals until ovulation. Growth of the dominant follicle was faster in Group A than in Groups B and C (1.3 vs. 0.3 and 0.7 mm/6h, P < 0.05) but diameters of the preovulatory follicles were similar - 44, 48 and 44 mm in Groups A, B and C, respectively. Similarly, reduction of endometrial folding (on a three point scale) during observation was higher in Group A than in B and C (2.1 vs. 1.2 and 1.8, A : B P < 0.05) but endometrial folding values in the term before ovulation were not different (0.6, 0.9 and 0.6 in Groups A, B and C). A positive correlation between the speed of follicular growth and reduction of endometrial folding was found (rs - 0.479, P = 0.003). Irregularity in follicle shape (the difference between the longest axis and its perpendicular axis) at the beginning of observation (3.3, 4.0 and 3.2 mm) was lower than before ovulation (7.4, 10.4 and 9.2 mm) in all groups (P < 0.01). The interval from the beginning of observation until ovulation was significantly shorter in Groups A and B versus C (37 and 31 vs. 103 h, P < 0.01). The results show that growth of dominant follicles after hCG is influenced by the size of the follicles at the time of treatment and correlates with reduction in endometrial folding as well as irregularity of follicle shape. Nevertheless, hCG treatment does not influence the size and shape of preovulatory follicles or endometrial folding immediately before ovulation.

Keywords: mare; induction of ovulation; ultrasonographical examination; follicle growth; follicle shape; ovulation

Published: January 31, 2012  Show citation

ACS AIP APA ASA Harvard Chicago Chicago Notes IEEE ISO690 MLA NLM Turabian Vancouver
Dolezel R, Ruzickova K, Maceckova G. Growth of the dominant follicle and endometrial folding after administration of hCG in mares during oestrus. Vet Med - Czech. 2012;57(1):36-41. doi: 10.17221/4970-VETMED.
Share...
Download citation
  • BibTeX (.bib)
  • Bookends (.ris)
  • EasyBib (.ris)
  • EndNote (.enw)
  • EndNote 8 (.xml)
  • ISI WoS (.isi)
  • Medlars (.medlars)
  • Mendeley (.ris)
  • MODS (.xml)
  • Papers (.ris)
  • RefWorks (.txt)
  • RefManager (.ris)
  • RIS (.ris)
  • MS Word (.xml)
  • Zotero (.ris)
    • Open full article

    References

    1. Ataman MB, Gunay A, Uzman M, Gunay U (2000): Ovulation induction with human chorionic gonadotropin (hCG) and gonadotropin releasing hormone (GnRH) in mares. Indian Journal of Animal Science 70, 810-812.
    2. Aurich C, Aurich JE, Klug E (1993): Possibilities of controlling the oestrous cycle in mares. Praktische Tierarztliche 74, 1001-1008.
    3. Berezovski CJ, Stitch KL, Wendt KM, Vest DJ (2004): Clinical comparison of 3 products available to hasten ovulation in cyclic mares. Journal of Equine Veterinary Science 24, 231-233. Go to original source...
    4. Bollwein H, Braun J (1999): Follicular dynamics in mares treated with HCG for induction of ovulation. Tierarztliche Praxis Ausgabe Grosstiere Nutztiere 27, 47-51.
    5. Bouakkaz A, Ouzrout R, Camillo F, Vannozzi I, Rota A, Romagnoli S, Aria G (2005): Time of ovulation after treatment with hCG in the mare. Assiut Veterinary Medical Journal 51, 331-335. Go to original source...
    6. Bruyas JF, Fieni F, Allaire F, Tainturier D (1992): Control of the oestrous cycle in mares. A review. Recueil de Medecine Veterinaire 168, 937-946.
    7. Bulbul B, Sonmez M (2007): The effect of various doses of hCG on induction of ovulation in mares. Indian Veterinary Journal 84, 712-714.
    8. Carnevale EM, McKinnon AO, Squires EL, Voss JL (1988): Ultrasonographic characteristics of the preovulatory follicle preceding and during ovulation in mares. Journal of Equine Veterinary Science 8, 428-431. Go to original source...
    9. Cetin H, Korkmaz O, Atli MO (2003): The effect of human chorionic gonadotropin administration at the time of mating on induction of ovulation and pregnancy rates in the purebred Arabian mares (in Turkish). Saglik Bilimleri Dergisi, Firat Universitesi (Veteriner) 17, 179-182.
    10. Chavatte P, Palmer E (1998): Induction of ovulation in the mare. Equine Veterinary Education 10, 26-30. Go to original source...
    11. Cox TJ, Squires EL, Carnevale EM (2009): Effect of follicle size and follicle-stimulating hormone on ovulation induction and embryo recovery in the mare. Journal of Equine Veterinary Science 29, 213-218. Go to original source...
    12. Cuervo-Arango J, Newcombe JR (2008): Repeatability of preovulatory follicular diameter and uterine edema pattern in two consecutive cycles in mare and how they are influenced by ovulation inductors. In: Proceedings of the European Equine Meeting - XIV SIVEFEEVA Congress, Venice, 357. Go to original source...
    13. Davidson DF (1947): The control of ovulation in the mare with reference to insemination with stored sperm. Journal of Agricultural Science 37, 287-290. Go to original source...
    14. Day FT (1939): Ovulation and descent of the ovum in the fallopian tube of the mare after treatment with gonadotropic hormones. Journal of Agricultural Science, Cambridge 29, 459-469. Go to original source...
    15. Duchamp G, Bour B, Combarnous Y, Palmer E (1987): Alternative solutions to hCG induction of ovulation in the mare. Journal of Reproduction and Fertility 35 (Suppl.), 221-228.
    16. Gastal EL, Silva LA, Gastal MO, Evans MJ (2006): Effect of different doses of hCG on diameter of the preovulatory follicle and interval to ovulation in mares. Animal Reproduction Science 94, 186-190. Go to original source...
    17. Ginther OJ, Pierson RA (1989): Regular and irregular characteristics of ovulation and the interovulatory interval in mares. Journal of Equine Veterinary Science 9, 4-12. Go to original source...
    18. Harrison LA, Squires EL, Mc Kinnon AO (1991): Comparison of HCG, buserelin and luprostiol for induction of ovulation in cyclic mares. Journal of Equine Veterinary Science 11, 163-166. Go to original source...
    19. Johnson AL, Becker SE (1993): Hormonal control of ovulation in the mare. Animal Reproduction Science 54, 1735-1745. Go to original source...
    20. Kahn W, Wolkmann D, Kenney RM (1994): Veterinary Reproductive Ultrasonography. Schlütersche Verlagsantalt und Druckerei GmbH & Co., Hannover. 256 pp.
    21. Kerban A, Dore M, Sirois J (1999): Characterisation of cellular and vascular changes in equine follicles during hCG-induced ovulation. Journal of Reproduction and Fertility 177, 115-123. Go to original source... Go to PubMed...
    22. Loy RG, Hughes JP (1966): The effect of human chorionic gonadotropin on ovulation, length of estrus, and fertility in the mare. Cornell Veterinary 56, 41-50.
    23. McKinnon AO, Squires EL, Carnevale EM (1987): Diagnostic ultrasonography of uterine patology in the mare. In: Proceedings of the 33rd Annual Conference of American Association of Equine Practitioners, 605-622.
    24. Moreli MCGD, Newcombe JR (2008): The efficacy of different hCG dose rates and the effect of hCG treatment on ovarian activity: ovulation, multiple ovulation, pregnancy, multiple pregnancy, synchrony of multiple ovulation; in the mare. Animal Reproduction Science 109, 189-199. Go to original source... Go to PubMed...
    25. Nishikawa, Y (1959): Studies on reproduction in horses. Japan Racing Association, Tokyo. 340 pp.
    26. Pace MM, Sulivan JJ (1975): Effect of timing of insemination, numbers of spermatozoa, and extender components on the pregnancy rate in mares inseminated with frozen stallion semen. Journal of Reproduction and Fertility 23 (Suppl.), 115-121.
    27. Palmer E (1987): New results on follicular growth and ovulation in the mare. In: Roche JF, O'Calagan D (eds.): Follicular Growth and Ovulation Rate in Farm Animals. Martinus Nijhof Publishers, Dordrecht. 237-255.
    28. Pierson RA, Ginther OJ (1985): Ultrasonic evaluation of the preovulatory follicle in the mare. Theriogenology 24, 359-368. Go to original source... Go to PubMed...
    29. Pycock JF (2002): Ultrasound characteristics of the uterus in the cycling mare and their correlation with steroid hormones and timing of ovulation. http://www.equinereproduction.com/articles/ultrasound-steroids.shtml.
    30. Samper JC (1997): Ultrasonographic appearance and the pattern of uterine edema to time ovulation in mare. In: Proceedings of the 43th Annual Convention of American Association of Equine Practitioners, 189.
    31. Samper JC (2008): Induction of estrus and ovulation: why same mares respond and other do not. Theriogenology 70, 445-447. Go to original source... Go to PubMed...
    32. Towson DH, Ginther OJ (1989): Size and shape changes in the preovulatory follicle in mares based on the digital analysis of ultrasonic images. Animal Reproduction Science 21, 63-71. Go to original source...
    33. Woods J, Bergfelt DR, Ginther OJ (1990): Effect of time of insemination relative to ovulation on pregnancy rate and embryonic loss rate in mares. Equine Veterinary Journal 22, 410-415. Go to original source... Go to PubMed...

    This is an open access article distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY NC 4.0), which permits non-comercial use, distribution, and reproduction in any medium, provided the original publication is properly cited. No use, distribution or reproduction is permitted which does not comply with these terms.


    Return to the content