Catania Salvatore, Gastaldelli Michele, Schiavon Eliana, Matucci Andrea, Tondo Annalucia, Merenda Marianna, Nicholas Robin A J
Istituto Zooprofilattico Sperimentale delle Venezie, viale Dell'Università 10, Legnaro (PD371735, Italy.
The Oaks, Nutshell Lane, Farnham, Surrey GU9 0HG, UK.
Pathogens. 2020 Jul 4;9(7):537. doi: 10.3390/pathogens9070537.
Italian beef production is mainly based on a feedlot system where calves are housed with mixed aged cattle often in conditions favourable to bovine respiratory disease (BRD). In Veneto, an indoor system is also used for imported bulls around 300-350 kg. Mycoplasmas, in particular and , contribute to BRD in young calves, but their role in the disease in older cattle has not been investigated. In this study, ten heads of cattle were selected from each of the 24 groups kept in 13 different farms. Bulls were sampled by nasal swabbing at 0, 15, and 60 days after arrival for isolation. Identification was carried out by 16S-rDNA PCR followed by denaturing gradient gel electrophoresis. , , and were identified, and prevalence was analysed by mixed-effects logistic regression models. This showed that most bulls arrived free of , but within two weeks, approximately 40% became infected, decreasing to 13% by the last sampling. In contrast, the prevalence of was not dependent on time or seasonality, while only showed a seasonality-dependent trend. The Italian fattening system creates an ideal environment for infection with , probably originating from previously stabled animals.
意大利的牛肉生产主要基于饲养场系统，在该系统中，犊牛常与不同年龄的牛混养在一起，所处环境往往有利于牛呼吸道疾病（BRD）的发生。在威尼托地区，对于体重约300 - 350千克的进口公牛也采用室内饲养系统。支原体，尤其是[具体支原体种类1]和[具体支原体种类2]，在幼龄犊牛的BRD中起作用，但它们在成年牛疾病中的作用尚未得到研究。在本研究中，从13个不同农场饲养的24组牛中每组挑选10头牛。公牛在到达后第0、15和60天通过鼻拭子采样以分离[支原体名称]。通过16S - rDNA PCR随后进行变性梯度凝胶电泳进行鉴定。鉴定出了[具体支原体种类1]、[具体支原体种类2]和[具体支原体种类3]，并通过混合效应逻辑回归模型分析其流行情况。结果表明，大多数公牛到达时未感染[具体支原体种类1]，但在两周内，约40%受到感染，到最后一次采样时降至13%。相比之下，[具体支原体种类2]的流行率不依赖于时间或季节性，而[具体支原体种类3]仅表现出依赖于季节的趋势。意大利的育肥系统为[具体支原体种类1]的感染创造了理想环境，其感染源可能来自先前饲养的动物。
