Division Visible Policing, Veterinary Science Services, Arcadia, South Africa.
Section of Reproduction, Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa.
Equine Vet J. 2021 Nov;53(6):1141-1149. doi: 10.1111/evj.13411. Epub 2021 Jan 20.
Surgical castration is one of the most frequently performed surgeries in horses and is associated with various post-surgical complications ranging in severity.
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.
Randomised open controlled trial.
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.
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.
A study population of young light horse breed colts and a relatively small sample size limited this pilot study.
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.
去势手术是马科动物中最常进行的手术之一，术后会出现各种不同严重程度的并发症。
我们研究了给公马注射抗 GnRH 疫苗以缩小睾丸大小，对随后的去势手术相关并发症发生率的影响。
随机开放对照试验。
19 匹公马随机分为三组。治疗组 V1-57 和 V2-100 在野外去势前，分别于第 57 天和第 100 天首次治疗后，接受两次 Improvac（Zoetis，南非）治疗。对照组也接受安慰剂治疗，然后在第 57 天进行去势。在疫苗接种前后和去势当天，对睾丸尺寸进行了连续测量，并采集血清样本以测量血清睾酮浓度（STC）和抗 GnRH 抗体滴度（ABT）。记录了 10 天的临床数据，以确定术后并发症。
所有接种疫苗的公马在去势时均表现出基础 STC 浓度，并出现强烈的 ABT 反应。第 57 天，V1-57 组和 V2-100 组的平均睾丸体积分别减少了 49.7%和 30.8%，而 V2-100 组在第 100 天去势时进一步减少了 63.9%。睾丸大小与术后包皮（P=0.001）和阴囊（P=0.025）肿胀显著相关。
本研究的研究人群为年轻轻型马品种公马，样本量相对较小，限制了本研究。
在去势前 28 天，给公马注射两次 Improvac，可有效缩小其睾丸体积，术后局部肿胀的发生率和严重程度均显著改善。这些结果可能为减轻野外去势相关的潜在术后并发症提供信息。
