Laboratório de Bacteriologia Veterinária, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
Programa de Pós-Graduação em Ciências Veterinárias, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
J Vet Diagn Invest. 2022 Jan;34(1):54-60. doi: 10.1177/10406387211050636. Epub 2021 Oct 7.
Poor reproductive performance in beef cattle caused by infectious agents results in major financial losses as a result of reduced pregnancy rates and extended calving intervals. Bulls can be subclinical chronic carriers of bacterial and protozoal agents involved in cow infertility, such as subsp. , , , , and . Bulls harbor these microorganisms in their preputial crypts and transmit the agents to cows during natural mating. To obtain an overview of the etiologic agents in the preputial mucus of bulls, we aimed to identify, by PCR assay, subsp. , , , , and in Brazilian bulls from farms with high infertility rates. We collected preputial mucus from 210 bulls on 18 beef cattle farms in Brazil between 2019 and 2020. We found at least one of the infectious agents that we were studying in bulls on 16 of the 18 beef cattle farms tested. We detected at least one infectious agent from 159 of 210 (76%) bulls tested, namely subsp. , , , , and in 87 (55%), 84 (53%), 45 (28%), 28 (18%), and 1 (0.6%) animal, respectively. We found 95 bulls (60%) positive for only 1 etiologic agent (single infection) and 64 bulls (40%) carried multiple agents. Our results demonstrate the occurrence of bacterial and protozoal infectious agents that may be related to infertility in Brazilian beef cattle herds.
由于受感染的病原体导致的牛繁殖性能低下，怀孕率降低和产犊间隔延长，从而导致了重大的经济损失。公牛可能是导致奶牛不孕的细菌和原生动物病原体的亚临床慢性携带者，例如、、、、和。公牛在其包皮隐窝中携带这些微生物，并在自然交配期间将病原体传播给奶牛。为了了解公牛包皮黏液中的病因，我们旨在通过 PCR 检测鉴定巴西农场中具有高不育率的公牛中的、、、、和 。我们于 2019 年至 2020 年间从巴西 18 个养牛场的 210 头公牛中采集了包皮黏液。我们在 18 个养牛场中的 16 个场的公牛中发现了至少一种我们正在研究的传染性病原体。我们在 210 头公牛中的 159 头（76%）中检测到至少一种传染性病原体，即、、、、和 在 87 头（55%）、84 头（53%）、45 头（28%）、28 头（18%）和 1 头（0.6%）动物中。我们发现 95 头公牛（60%）仅对 1 种病原体呈阳性（单一感染），而 64 头公牛（40%）携带多种病原体。我们的结果表明，巴西肉牛群中存在可能与不孕有关的细菌和原生动物传染性病原体。
