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Home / Equine Research Bank / Anim Reprod Sci / Suppression of testicular function and sexual behavior by va...
Animal reproduction science2008; 115(1-4); 88-102; doi: 10.1016/j.anireprosci.2008.11.011

Suppression of testicular function and sexual behavior by vaccination against GnRH (Equity) in the adult stallion.

Abstract: The aim of this study was to evaluate the effects of an anti-GnRH vaccine on testosterone concentration, antibody titer, scrotal width, semen quality and sexual behavior in the stallion. Adverse reactions to the vaccine were also determined. Eight clinically healthy sexually experienced stallions aged between 6 and 15 years from the National Stud in Avenches (Switzerland) were used. Five stallions were immunized 3 times at an interval of 4 and 8 weeks, respectively, with 200 microg of a GnRH-protein conjugate (Equity, CSL Limited, Australia) intramuscularly in the neck and 3 control animals received an equivalent volume of saline solution. Plasma testosterone concentrations and GnRH antibody titers as well as semen quality and libido were determined weekly during 1 year (52 weeks). In addition, scrotal width was measured in all stallions before and 4, 8 as well as 12 months after first vaccination. Our results demonstrate that in 4 stallions plasma testosterone started to decrease after the second vaccination and remained suppressed for at least 6 months whereas one stallion showed no effect. Until the end of the experiment 2 stallions reached prevaccination testosterone values. Antibody titers varied individually in all 5 stallions and reached peak concentrations within 2 weeks after the third vaccination. Scrotal width was significantly (P<0.05) lower in vaccinated than in control stallions 8 months after first vaccination. Semen quality started to decreased after the second vaccination and improved towards the end of the experiment. In 4 stallions libido was clearly reduced after the second immunization but normalized in 2 animals before the end of the study while 2 stallions continued to show poor libido. From our results we conclude that three immunizations with Equity are well tolerated in the stallion and may effectively suppress testosterone secretion and reduce semen quality as well as sexual behavior. The inhibiting activity of Equity on these parameters is individually different and may last for a minimum of 6 months.
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Publication Date: 2008-11-20 PubMed ID: 19128902DOI: 10.1016/j.anireprosci.2008.11.011Google Scholar: Lookup
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  • Journal Article

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 explores the impact of an anti-GnRH vaccine, used on adult stallions, on testosterone levels, sexual behavior, semen quality, and other associated parameters. It was found that the vaccine had effects for a minimum duration of six months, suppressing testosterone production, reducing semen quality, and altering sexual behaviors.

Study Design and Participants

  • The study involved eight healthy, sexually experienced stallions aged between 6 and 15 years belonging to the National Stud in Avenches, Switzerland.
  • Five of these stallions were subject to three immunizations with 200 micrograms of a GnRH-protein conjugate vaccine (Equity) while the remaining three stallions served as the control group, receiving saline solution instead.
  • The vaccinations were administered intramuscularly in the neck at intervals of 4 and 8 weeks.

Research Methodology

  • The researchers evaluated multiple aspects for more than a year – plasma testosterone concentrations, GnRH antibody titers, semen quality, sexual libido, and scrotal width.
  • Scrotal width was measured before the vaccination and again after 4, 8, and 12 months.

Results

  • In four of the stallions vaccinated, there was a decrease in plasma testosterone beginning after the second vaccination, which remained suppressed for at least six months. However, one out of the five vaccinated stallions showed no such effect.
  • Antibody titers reached peak concentrations within two weeks after the third vaccination, with variations observed among the stallions.
  • There was a significant decrease in scrotal width in the vaccinated stallions as compared to the control group, eight months after the first vaccination.
  • Semen quality too started decreasing post the second vaccination but saw an improvement towards the end of the experiment.
  • Libido was visibly reduced in four of the vaccinated stallions after the second immunization, although it gradually normalized in two of these animals by the end of the study.

Conclusion

  • The study concludes that the use of the Equity vaccine in stallions is generally well tolerated.
  • It effectively suppresses testosterone production, reduces semen quality, and alters sexual behavior for a minimum duration of six months.
  • However, the inhibiting activity of the vaccine on these parameters differed among individual stallions.

Cite This Article

APA
Janett F, Stump R, Burger D, Thun R. (2008). Suppression of testicular function and sexual behavior by vaccination against GnRH (Equity) in the adult stallion. Anim Reprod Sci, 115(1-4), 88-102. https://doi.org/10.1016/j.anireprosci.2008.11.011

Publication

Animal reproduction science
ISSN: 1873-2232
NlmUniqueID: 7807205
Country: Netherlands
Language: English
Volume: 115
Issue: 1-4
Pages: 88-102

Researcher Affiliations

Janett, F
  • Clinic for Reproductive Medicine, University of Zürich, Winterthurerstrasse 260, CH-8057 Zürich, Switzerland. fjanett@vetclinics.uzh.ch
Stump, R
    Burger, D
      Thun, R

        MeSH Terms

        • Animals
        • Antibody Formation
        • Ejaculation
        • Female
        • Gonadotropin-Releasing Hormone / immunology
        • Gonadotropin-Releasing Hormone / pharmacology
        • Horses
        • Luteinizing Hormone / antagonists & inhibitors
        • Luteinizing Hormone / immunology
        • Male
        • Ovariectomy
        • Penile Erection
        • Semen / physiology
        • Sexual Behavior, Animal / drug effects
        • Sexual Behavior, Animal / physiology
        • Sperm Count
        • Spermatozoa / abnormalities
        • Spermatozoa / drug effects
        • Testis / drug effects
        • Testis / physiology
        • Testosterone / blood
        • Testosterone / immunology
        • Vaccines / adverse effects
        • Vaccines / pharmacology

        Citations

        This article has been cited 17 times.
        1. Botha AE, Schulman ML, Birrell J, du Plessis L, Laver PN, Soley J, Colenbrander B, Bertschinger HJ. Effects of an anti-gonadoliberin releasing hormone vaccine on testicular, epididymal and spermatogenic development in the horse. Reprod Domest Anim 2022 Aug;57(8):919-927.
          doi: 10.1111/rda.14141pubmed: 35500167google scholar: lookup
        2. Schwarzenberger F, Krawinkel P, Jeserschek SM, Schauerte N, Geiger C, Balfanz F, Knauf-Witzens T, Sicks F, Martinez Nevado E, Anfray G, Hein A, Kaandorp-Huber C, Marcordes S, Venshøj B. Immunocontraception of male and female giraffes using the GnRH vaccine Improvac®. Zoo Biol 2022 Jan;41(1):50-64.
          doi: 10.1002/zoo.21651pubmed: 34478196google scholar: lookup
        3. Ahn HS, Park BJ, Go HJ, Lyoo EL, Kim DH, Lee JB, Park SY, Song CS, Lee SW, Choi YK, Jung HJ, Kim HM, Choi IS. Induction of immunocontraceptive effects in both male and female mice immunized with GnRH vaccine. Vet Med Sci 2021 Sep;7(5):1999-2007.
          doi: 10.1002/vms3.563pubmed: 34236748google scholar: lookup
        4. Ponthier J, Rigaux G, Parrilla-Hernandez S, Egyptien S, Gatez C, Carrasco Leroy C, Deleuze S. Case Report: Suppression of Harem Stallion Behavior and Fertility Following Anti-Gonadotropin-Releasing Hormone Vaccination of a Captive Wild Przewalski's Horse (Equus ferus przewalskii). Front Vet Sci 2020;7:569185.
          doi: 10.3389/fvets.2020.569185pubmed: 33330690google scholar: lookup
        5. Siel D, Ubilla MJ, Vidal S, Loaiza A, Quiroga J, Cifuentes F, Hardman T, Lapierre L, Paredes R, Sáenz L. Reproductive and Behavioral Evaluation of a New Immunocastration Dog Vaccine. Animals (Basel) 2020 Jan 31;10(2).
          doi: 10.3390/ani10020226pubmed: 32023851google scholar: lookup
        6. Lee YJ, Jo EJ, Lee HW, Hwang BR, Kim YH, Park BJ, Cho YJ, Lee YA, Choi IS, Han JS. Evaluation of infertility efficacy of the E. coli expressed STF2-GnRH vaccine in male cats. J Vet Sci 2019 May;20(3):e30.
          doi: 10.4142/jvs.2019.20.e30pubmed: 31161748google scholar: lookup
        7. He Y, Li H, Zhang Y, Hu J, Shen Y, Feng J, Zhao X. Comparative Analysis of Mitochondrial Proteome Reveals the Mechanism of Enhanced Ram Sperm Motility Induced by Carbon Ion Radiation After In Vitro Liquid Storage. Dose Response 2019 Jan-Mar;17(1):1559325818823998.
          doi: 10.1177/1559325818823998pubmed: 30733653google scholar: lookup
        8. Lueders I, Young D, Maree L, van der Horst G, Luther I, Botha S, Tindall B, Fosgate G, Ganswindt A, Bertschinger HJ. Effects of GnRH vaccination in wild and captive African Elephant bulls (Loxodonta africana) on reproductive organs and semen quality. PLoS One 2017;12(9):e0178270.
          doi: 10.1371/journal.pone.0178270pubmed: 28915245google scholar: lookup
        9. Jeannerat E, Janett F, Sieme H, Wedekind C, Burger D. Quality of seminal fluids varies with type of stimulus at ejaculation. Sci Rep 2017 Mar 13;7:44339.
          doi: 10.1038/srep44339pubmed: 28287188google scholar: lookup
        10. Burger D, Dolivo G, Wedekind C. Ejaculate Characteristics Depend on Social Environment in the Horse (Equus caballus). PLoS One 2015;10(11):e0143185.
          doi: 10.1371/journal.pone.0143185pubmed: 26599821google scholar: lookup
        11. Burger D, Dolivo G, Marti E, Sieme H, Wedekind C. Female major histocompatibility complex type affects male testosterone levels and sperm number in the horse (Equus caballus). Proc Biol Sci 2015 May 22;282(1807):20150407.
          doi: 10.1098/rspb.2015.0407pubmed: 25904670google scholar: lookup
        12. Ganaie JA, Gautam V, Shrivastava VK. Effects of Kamdhenu Ark and Active Immunization by Gonadotropin Releasing Hormone Conjugate (GnRH-BSA) on Gonadosomatic Indices (GSI) and Sperm Parameters in Male Mus musculus. J Reprod Infertil 2011 Jan;12(1):3-7.
          pubmed: 23926493
        13. Benavides Valades G, Ganswindt A, Annandale H, Schulman ML, Bertschinger HJ. Non-invasive assessment of the reproductive cycle in free-ranging female African elephants (Loxodonta africana) treated with a gonadotropin-releasing hormone (GnRH) vaccine for inducing anoestrus. Reprod Biol Endocrinol 2012 Aug 25;10:63.
          doi: 10.1186/1477-7827-10-63pubmed: 22921012google scholar: lookup
        14. Ubilla MJ, Lopez-Bejar M, Siel D, Sáenz L. Reproductive Control in Dogs with Emphasis on Anti-GnRH Immunocastration and Its Behavioral Effects. Vet Sci 2025 Dec 20;13(1).
          doi: 10.3390/vetsci13010005pubmed: 41600661google scholar: lookup
        15. An DJ, Shin JH, Choe S, Lee YH, Jang MK, An BH, Park GN, Cho YS, Chang KS. Immunogenicity and Contraceptive Potential of a Classical Swine Fever Viral Vector Live Vaccine Strain Containing Pig Gonadotropin-Releasing Hormone. Vaccines (Basel) 2025 Oct 12;13(10).
          doi: 10.3390/vaccines13101048pubmed: 41150436google scholar: lookup
        16. Siel D, Huenchullán PR, Vidal S, Valdés A, Sáenz L. Improving Beef Cattle Production: Safety and Effectiveness of New Immunocastration Vaccine. Animals (Basel) 2024 Aug 31;14(17).
          doi: 10.3390/ani14172538pubmed: 39272323google scholar: lookup
        17. Khumsap S, Tangtrongsup S, Towiboon P, Somgird C. GnRH Vaccine Could Suppress Serum Testosterone in Stallion Mules. Animals (Basel) 2024 Jun 17;14(12).
          doi: 10.3390/ani14121800pubmed: 38929419google scholar: lookup
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