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Equine veterinary journal2021; 53(6); 1141-1149; doi: 10.1111/evj.13411

Vaccination against GnRH as a prelude to surgical castration of horses.

Abstract: Surgical castration is one of the most frequently performed surgeries in horses and is associated with various post-surgical complications ranging in severity. Objective: We investigated the effects of administering an anti-GnRH vaccine to colts for reduction of testis size on the incidence of complications associated with their subsequent surgical castration. Methods: Randomised open controlled trial. Methods: Nineteen colts were randomly assigned to one of the three groups. Treatment Groups V1-57 and V2-100 received two treatments of Improvac (Zoetis, South Africa) before their castration in the field on either Day 57 or Day 100 following first treatment, respectively. Controls similarly received placebo treatments followed by castration on Day 57. Serial measurements of testicular dimensions and serum samples for measuring serum testosterone concentrations (STCs) and anti-GnRH antibody titres (ABTs) were obtained pre- and post-vaccination and on the day of castration. Clinical data recorded for 10 days determined post-surgical complications. Results: All vaccinated colts showed a baseline STC concentration at castration with a strong ABT response. Mean testicular volume of Groups V1-57 and V2-100 reduced by 49.7% and 30.8%, respectively, on Day 57 and this further reduced in Group V2-100 by 63.9% at castration on Day 100. Testis size was significantly correlated with post-surgical preputial (P = 0.001) and scrotal (P = 0.025) swelling. Conclusions: A study population of young light horse breed colts and a relatively small sample size limited this pilot study. Conclusions: Administering two doses of Improvac in colts 28 days apart prior to castration effectively reduced their testicular volumes with associated significant post-surgical improvement in both the incidence and degree of local swelling. These results may inform mitigation of potential post-surgical complications associated with castration in the field.
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Publication Date: 2021-01-20 PubMed ID: 33354803DOI: 10.1111/evj.13411Google Scholar: Lookup
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  • Journal Article
  • Randomized Controlled Trial
  • Veterinary

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.

This research investigated the use of an anti-GnRH vaccine in horses prior to their surgical castration, to reduce testicular size and post-surgical complications. The results showed that administering the vaccine led to significantly reduced testicular volume and subsequently decreased incidence and degree of local swelling after the surgery.

Study Overview

The study focused on the use of an anti-Gonadotropin-releasing hormone (GnRH) vaccine which might be useful before surgical castration of male horses or colts, performed to reduce complications related to this commonly performed procedure.

  • 19 colts were subjected in a randomized, open, controlled trial, where they were categorized into one of the three groups. The V1-57 and V2-100 groups were given two treatments of an anti-GnRH vaccine (Improvac by Zoetis) prior to castration, whereas the control group was given a placebo before surgery.
  • Data was collected through serial measurements of testicular dimensions and samples were acquired to measure serum testosterone concentrations (STCs) and anti-GnRH antibody titres (ABTs) before and after vaccination as well as on the day of castration.
  • Clinical data, measured for ten days post-operation, were used to determine post-surgical complications.

Findings of the Study

The results showed a marked difference between the treated groups versus the control group.

  • All vaccinated colts showed a baseline level of STC concentration at the time of castration alongside strong ABT response.
  • The mean testicular volume of groups V1-57 and V2-100 was reduced by 49.7% and 30.8%, respectively, on Day 57; this reduction further increased in Group V2-100 by 63.9% at castration on Day 100.
  • The researchers found a significant correlation between testes size and post-surgical preputial and scrotal swelling (P<0.025).

Conclusion

Based on the results of this pilot study with a relatively small sample size,

  • Administering two doses of Improvac in colts 28 days apart before castration effectively reduced their testicular volumes and associated post-surgical swelling.
  • The findings of this study might aid in decreasing potential post-surgical complications connected with horse’s castration performed in non-clinical conditions, or “in the field”.

Cite This Article

APA
Birrell JR, Schulman ML, Botha AE, Ganswindt A, Fosgate GT, Bertschinger HJ. (2021). Vaccination against GnRH as a prelude to surgical castration of horses. Equine Vet J, 53(6), 1141-1149. https://doi.org/10.1111/evj.13411

Publication

Equine veterinary journal
ISSN: 2042-3306
NlmUniqueID: 0173320
Country: United States
Language: English
Volume: 53
Issue: 6
Pages: 1141-1149

Researcher Affiliations

Birrell, John R
  • Division Visible Policing, Veterinary Science Services, Arcadia, South Africa.
Schulman, Martin L
  • Section of Reproduction, Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa.
Botha, Alma E
  • Mammal Research Institute, Department of Zoology and Entomology, Faculty of Natural and Agricultural Sciences, University of Pretoria, Pretoria, South Africa.
Ganswindt, André
  • Section of Reproduction, Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa.
  • Mammal Research Institute, Department of Zoology and Entomology, Faculty of Natural and Agricultural Sciences, University of Pretoria, Pretoria, South Africa.
Fosgate, Geoffrey T
  • Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa.
Bertschinger, Henk J
  • Section of Reproduction, Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa.

MeSH Terms

  • Animals
  • Gonadotropin-Releasing Hormone
  • Horses
  • Male
  • Orchiectomy / veterinary
  • Pilot Projects
  • Testis
  • Testosterone
  • Vaccination / veterinary

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Citations

This article has been cited 3 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. Tyrnenopoulou P, Flouraki E, Folias L, Loukopoulos E, Starras A, Chalvatzis P, Tsioli V, Mavrogianni VS, Fthenakis GC. Complications Following Orchiectomy in Stallions in Field Conditions: Descriptive Results and Predictors in a Study of 612 Cases. Animals (Basel) 2026 Jan 21;16(2).
    doi: 10.3390/ani16020326pubmed: 41594514google scholar: lookup
  3. Wang C, Yang C, Zeng Y, Zhang M. GnRH-immunocastration: an alternative method for male animal surgical castration. Front Vet Sci 2023;10:1248879.
    doi: 10.3389/fvets.2023.1248879pubmed: 38026623google scholar: lookup
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