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Reversibility of the effects of GnRH-vaccination used to suppress reproductive function in mares.
Abstract: Active immunisation against gonadotrophin-releasing hormone (GnRH) provides a reversible method for control of oestrous behaviour and fertility in mares. Previous reports failed to demonstrate the interval to resumption of cyclic ovarian activity after GnRH-vaccination. Objective: Administration of the GnRH-vaccine Improvac in a large group of mares of various ages will result in effective, reliably reversible suppression of ovarian activity within a 2 year period. Methods: The mares, subdivided into 3 age categories, were vaccinated twice (with a 35 day interval) using 400 µg Improvac and monitored via blood samples until Day 720 after initial vaccination for serum progesterone concentration determination by radioimmune assay and anti-GnRH antibody titre by enzyme immunoassay. Samples were collected until individuals resumed cyclic ovarian activity. Results: All mares showed suppression of cyclic ovarian activity by clinical examination and serum progesterone concentration (SPC) ≤ 1 nmol/l by Day 70 and 92.2% resumed cyclic activity by SPC at Day 720 with a mean interval = 417.8 days (s.d. ± 23.9; range 232-488 days, median 344 days). A significant age effect (P = 0.028) on the interval, but not on GnRH-antibody titre response, was observed between the youngest (≤ 4 years) and oldest (≥ 11 years) categories. Conclusions: Immunising adult mares of all ages with Improvac resulted in a reversible suppression of cyclic ovarian activity in most mares. An age effect, with the youngest mares showing a longer interval to reversibility, was observed.
© 2012 EVJ Ltd.
Publication Date: 2012-05-06 PubMed ID: 22563805DOI: 10.1111/j.2042-3306.2012.00577.xGoogle Scholar: Lookup The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The paper discusses a study on the use of GnRH-vaccine for controlling the fertility and oestrous behaviour in mares, which found that ovarian activity can be suppressed and made reversible in most mares regardless of their age.
Research Objective
The aim of the study was to test the application of Improvac, which is a GnRH vaccine, in a large group of mares of varying ages. The target result was to achieve reliable and reversible suppression of ovarian activity within a period of 2 years after the initial vaccination.
Methodology
The mares in the study were divided into three different age groups.
- They were vaccinated twice with a gap of 35 days, each time with 400 µg of Improvac.
- The researchers monitored them by collecting blood samples up to Day 720 following the initial vaccination.
- The samples were analysed for serum progesterone concentration (SPC) through a radioimmune assay and anti-GnRH antibody titre through an enzyme immunoassay.
- Sampling continued until the individual mares resumed cyclic ovarian activity.
Results
All the mares were found to have suppressed cyclic ovarian activity by either clinical examination or reaching an SPC level of ≤ 1 nmol/l by Day 70.
- By Day 720, 92.2% of the mares resumed their cyclic activity, as indicated by SPC.
- The mean interval for the resumption of ovarian activity was found to be 417.8 days, with a standard deviation of ± 23.9 and range between 232 and 488 days.
- An age effect was also observed to influence the interval to reversibility, with younger mares (≤ 4 years) showing a longer gap compared to the oldest category (≥ 11 years), but it didn’t affect the response to GnRH-antibody titre.
Conclusion
The study concluded that immunization of adult mares of all age groups with Improvac leads to reversible suppression of cyclic ovarian activity in most of the subject animals. An age effect does exist, with younger mares taking longer to reverse their suppressed ovarian activities as compared to older mares.
Cite This Article
APA
Schulman ML, Botha AE, Muenscher SB, Annandale CH, Guthrie AJ, Bertschinger HJ.
(2012).
Reversibility of the effects of GnRH-vaccination used to suppress reproductive function in mares.
Equine Vet J, 45(1), 111-113.
https://doi.org/10.1111/j.2042-3306.2012.00577.x Publication
Researcher Affiliations
- Section of Reproduction, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa. martin.schulman@up.ac.za
MeSH Terms
- Animals
- Antibodies / blood
- Estrus / drug effects
- Female
- Gonadotropin-Releasing Hormone / immunology
- Gonadotropin-Releasing Hormone / pharmacology
- Horses / blood
- Horses / physiology
- Immunization / veterinary
- Immunization Schedule
- Sexual Behavior, Animal / drug effects
- Time Factors
- Vaccines, Contraceptive / immunology
Citations
This article has been cited 9 times.- French H, Segabinazzi L, Middlebrooks B, Peterson E, Schulman M, Roth R, Crampton M, Conan A, Marchi S, Gilbert T, Knobel D, Bertschinger H. Efficacy and Safety of Native and Recombinant Zona Pellucida Immunocontraceptive Vaccines Formulated with Non-Freund's Adjuvants in Donkeys. Vaccines (Basel) 2022 Nov 24;10(12).
- 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.
- Aurich C, Kaps M. Suppression of reproductive behaviour and gonadal function in female horses-An update. Reprod Domest Anim 2022 Sep;57 Suppl 4(Suppl 4):4-12.
- 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.
- Kawase K, Tomiyasu J, Ban K, Ono R, Ando S, Ono A, Kimura R, Tomisawa K, Matsui M, Shiihara SI. Contraceptive effect of a gonadotropin-releasing hormone vaccine on a captive female African Lion (Panthera leo): a case study. J Vet Med Sci 2021 Sep 15;83(9):1454-1458.
- 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.
- Han YG, Liu GQ, Jiang XP, Xiang XL, Huang YF, Nie B, Zhao JY, Nabeel I, Tesema B. Reversibility and safety of KISS1 metastasis suppressor gene vaccine in immunocastration of ram lambs. Asian-Australas J Anim Sci 2018 Jun;31(6):835-841.
- Hermes R, Schwarzenberger F, Göritz F, Oh S, Fernandes T, Bernardino R, Leclerc A, Greunz E, Mathew A, Forsyth S, Saragusty J, Hildebrandt TB. Ovarian down Regulation by GnRF Vaccination Decreases Reproductive Tract Tumour Size in Female White and Greater One-Horned Rhinoceroses. PLoS One 2016;11(7):e0157963.
- Khumsap S, Tangtrongsup S, Towiboon P, Somgird C. GnRH Vaccine Could Suppress Serum Testosterone in Stallion Mules. Animals (Basel) 2024 Jun 17;14(12).
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