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Vaccination against GnRH as a prelude to surgical castration of horses
Dissertation (MSc (Veterinary Science))--University of Pretoria, 2017.
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| Format: | Thesis |
| Language: | English |
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2026
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| _version_ | 1867613643487576064 |
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| access_status_str | Open Access |
| author2 | Bertschinger, H.J. |
| author_browse | Bertschinger, H.J. |
| author_facet | Bertschinger, H.J. |
| collection | Thesis |
| description | Dissertation (MSc (Veterinary Science))--University of Pretoria, 2017. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/110140 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:39:24.464Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2026 |
| publishDateRange | 2026 |
| publishDateSort | 2026 |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/110140 Vaccination against GnRH as a prelude to surgical castration of horses Bertschinger, H.J. u86112709@tuks.co.za Schulman, M.L. Ganswindt, Andre Birrell, John Robertson GnRH Vaccine Testis Complications Colts Castration Dissertation (MSc (Veterinary Science))--University of Pretoria, 2017. Surgical castration of young colts before the onset of problematic masculine behaviour is reported as one of the most commonly performed surgical procedures in the horse. Complications that are reported following surgical castration include excessive scrotal swelling, haemorrhage, scirrhous cord formation, peritonitis, omental herniation, incisional infections, hydrocoele, penile trauma, organ eventration, unaltered behaviour and anaesthetic incidents. There is no literature on the possible effects of GnRH vaccination on post-surgical outcomes of castration in the horse. This study hypothesised that the use of a GnRH vaccine as a prelude to castration in the horse would result in a decrease in testicular size with resultant fewer post-surgical complications. The objective of this study was to investigate if the prior administration of two doses of the GnRH vaccine Improvac® could reduce the incidence of complications associated with routine in-the-field surgical castration of horse colts 15 to 18 months of age. The study was conducted over a period of 100 days during the winter months of June to August 2012 in the Republic of South Africa, North West Province in the town of Potchefstroom. Nineteen colts were randomly assigned to 3 groups: Groups 1 (n=7) and 2 (n=6) were treated with two GnRH vaccinations 30 days apart before being castrated on Day 57 (Group 1) or Day 100 (Group 2), respectively; Group 3 colts (n=6) received two placebo vaccinations 30 days apart and were castrated on Day 57. Testicular dimensions were assessed in situ prior to surgery and after castration. Serum testosterone concentration was assessed before and at various intervals after Improvac® treatment. Post castration for a period of 10 days the clinical variables of temperature, heart and respiratory rates were recorded. In addition appetite, habitus, scrotal and preputial swelling and scrotal wound discharge were monitored daily during the same period using a 3 to 4 point scoring system. A significant decrease (p≤ 0.001) in serum testosterone concentration and testicular volume (p=0.001) was found in the treated animals (Group 1 and 2). The suppressive effect was consistent in all 13 treated colts. In the control animals (Group 3), serum testosterone levels (p=0.202) as well as testicular volume (p= 0.845) remained unchanged. Testicular volume and mass were significantly correlated in all three groups (Group 1: r2 =0.95, p=0.0018; Group 2: r2 =0.95, p=0.0019; Group 3: r2 =0.993, 2 p=0.0008). Post-castration epididymal mass was not significantly affected by the GnRH vaccine treatment. Although the mean epididymal mass of Groups 1 and 2 combined was smaller than that of Group 3, the difference was not significant. Only one colt (# 19) in the control group developed a severe febrile reaction, severe scrotal and preputial swelling and a severe wound discharge following castration. These were accompanied by increased heart and respiratory rates, and decreased appetite and habitus scores and required treatment, after which he made an uneventful recovery. The mean temperatures, heart rates, appetite and habitus scores of Groups 1 and 2 did not differ significantly from those of the control group. Mean respiratory rate of the treated groups was, however, significantly lower than the control group mean (p=0.010). The scrotal swelling of Groups 1 and 2 was significantly lower than that of the controls on days 4 to 7 (p=0.007) and 8 to 10 (p=0.003). This did not apply to preputial swelling where there was no significant difference. Similar to other studies, scrotal swelling reached a maximum on Days 3 to 6 post castration and was resolved by Day 9. Moderate scrotal swelling after castration is regarded as normal and not considered a complication. No other complications such as evisceration of omental tissue or intestinal loops occurred. The most significant finding of the study was a positive correlation between testicular mass and preputial (p Production Animal Studies MSc (Veterinary Science) 2026-05-15T17:26:25Z 2026-05-15T17:26:25Z 17/01/13 2017 Dissertation http://hdl.handle.net/2263/110140 en application/pdf |
| spellingShingle | GnRH Vaccine Testis Complications Colts Castration Vaccination against GnRH as a prelude to surgical castration of horses |
| title | Vaccination against GnRH as a prelude to surgical castration of horses |
| title_full | Vaccination against GnRH as a prelude to surgical castration of horses |
| title_fullStr | Vaccination against GnRH as a prelude to surgical castration of horses |
| title_full_unstemmed | Vaccination against GnRH as a prelude to surgical castration of horses |
| title_short | Vaccination against GnRH as a prelude to surgical castration of horses |
| title_sort | vaccination against gnrh as a prelude to surgical castration of horses |
| topic | GnRH Vaccine Testis Complications Colts Castration |
| url | http://hdl.handle.net/2263/110140 |