National Wildlife Management Centre, Animal and Plant Health Agency, York, United Kingdom.
Agriculture, Fisheries and Conservation Department, Animal Management (Operation) Division, Hong Kong SAR, China.
PLoS One. 2022 Aug 17;17(8):e0272604. doi: 10.1371/journal.pone.0272604. eCollection 2022.
Increasing human-wildlife conflicts worldwide are driving the need for multiple solutions to reducing "problem" wildlife and their impacts. Fertility control is advocated as a non-lethal tool to manage free-living wildlife and in particular to control iconic species. Injectable immunocontraceptives, such as GonaCon, stimulate the immune system to produce antibodies against the gonadotrophin-releasing hormone (GnRH), which in turn affects the release of reproductive hormones in mammals. Feral cattle (Bos indicus or Bos taurus) in Hong Kong are an iconic species whose numbers and impacts on human activities have increased over the last decade. Previous studies have proven that a primer vaccination and booster dose of GonaCon in female cattle are safe and effective in reducing pregnancy levels one year post-treatment. The aims of this project were 1. to evaluate the longevity of the effect of GonaCon in feral cattle up to four years post-vaccination; and 2. to assess if a second booster dose of GonaCon, administered at either two or four years post-vaccination, extends the contraceptive effect in this species. Vaccination with GonaCon, administered as a primer and booster dose, was effective in causing significant infertility in free-living cattle for at least three years post-vaccination, with the percentage of pregnant animals in the vaccinated group decreasing from 76% at vaccination to 35%, 19% and 7% in years 2, 3 and 4 post-vaccination, compared with 67% at vaccination to 50%, 57% and 14% respectively in the control group. A second booster dose of GonaCon administered either 2 or 4 years after vaccination rendered 100% of the Treated cattle infertile for at least another year. These results suggested that vaccination with GonaCon can reduce feral cattle population growth and that a second booster dose can extend the longevity of the contraceptive effect.
随着全球范围内人与野生动物冲突的不断增加，需要采用多种方法来减少“问题”野生动物及其影响。生育控制被提倡作为一种非致命工具来管理野生动物，特别是控制标志性物种。可注射的免疫避孕药，如 GonaCon，刺激免疫系统产生针对促性腺激素释放激素（GnRH）的抗体，进而影响哺乳动物生殖激素的释放。香港的野牛（Bos indicus 或 Bos taurus）是一种标志性物种，其数量及其对人类活动的影响在过去十年中有所增加。先前的研究已经证明，对雌性牛进行 GonaCon 的基础免疫和加强免疫是安全有效的，可以将治疗后一年的怀孕水平降低。本项目的目的是：1. 评估 GonaCon 在野牛中的作用持续时间，最长可达接种后四年；2. 评估在接种后两年或四年进行第二次 GonaCon 加强免疫是否可以延长这种动物的避孕效果。GonaCon 的接种，作为基础免疫和加强免疫，在接种后至少三年内有效地导致了自由放养牛的显著不育，接种组中怀孕动物的百分比从接种时的 76%下降到接种后 2、3 和 4 年的 35%、19%和 7%，而对照组分别从 67%下降到 50%、57%和 14%。在接种后两年或四年给予第二次 GonaCon 加强免疫，使 100%的处理牛至少在另一年内不育。这些结果表明，GonaCon 的接种可以减少野牛的种群增长，并且第二次加强免疫可以延长避孕效果的持续时间。
