Botulism is a neuroparalytic intoxication, usually fatal, caused by the botulinum toxins (BoNTs). Vaccination is the best-known strategy to prevent this disease in ruminants. Serotypes C and D and their variants CD and DC are the main types responsible for botulism in bovine and buffaloes in Brazil and cattle in Japan and Europe. Brazil has a herd of approximately 1.39 million buffaloes and is the largest producer in the Western world. This study aimed to assess the humoral immune response of buffaloes during the 12-month period after vaccination against BoNT serotypes C and D with a recombinant vaccine in three different concentrations (100, 200, and 400 μg) of non-purified recombinant proteins (Vrec) and also with a bivalent commercial toxoid (Vcom). Vrec400 was the best vaccine among those tested because it induced higher levels of antibodies and maintained higher levels of antibodies for the longest time, while Vrec200 could be considered the most cost-effective vaccine for large-scale production. None of the vaccines were able to promote continuous immunological protection within the timeframe proposed by the current Brazilian vaccination protocol. Further studies should focus on vaccine adjustments to ensure continued humoral protection against botulism.

肉毒杆菌中毒是由肉毒杆菌毒素（BoNT）引起的神经麻痹性中毒，通常是致命的。接种疫苗是防止反刍动物中这种疾病的最著名策略。血清型C和D及其变体CD和DC是造成巴西牛和水牛肉毒中毒以及日本和欧洲牛的肉毒中毒的主要类型。巴西拥有约139万头水牛，是西方世界最大的生产国。这项研究旨在评估使用三种不同浓度（100、200和400μg）非纯化重组蛋白（Vrec）的重组疫苗对BoNT血清型C和D接种水牛后的12个月内的体液免疫反应）以及二价商业类毒素（Vcom）。Vrec400是测试过的最好的疫苗，因为它可以诱导更高水平的抗体并在最长的时间内保持更高水平的抗体，而Vrec200被认为是大规模生产中最具成本效益的疫苗。在目前的巴西疫苗接种方案建议的期限内，没有一种疫苗能够促进持续的免疫保护。进一步的研究应侧重于疫苗的调整，以确保持续的体液保护免受肉毒杆菌中毒。