College of Food, Agricultural, and Environmental Sciences, Department of Food Science and Technology, The Ohio State University, Columbus, OH, USA.
College of Veterinary Medicine, Department of Veterinary Preventive Medicine, The Ohio State University, Columbus, OH, USA.
Prev Vet Med. 2021 May;190:105323. doi: 10.1016/j.prevetmed.2021.105323. Epub 2021 Mar 5.
Calf gastrointestinal disease remains one of the main causes of productivity and economic losses on dairy operations. The majority of pre-weaned calf mortality is attributed to diarrhea or other digestive problems. Five enteric pathogens are commonly associated with diarrhea in dairy calves, including bovine rotavirus, bovine coronavirus, Escherichia coli, Salmonella spp., and Cryptosporidium parvum. Pathogen-associated differences in health outcomes and case fatality rates have not been well-characterized. Additionally, updated prevalence estimates may reflect important changes in the epidemiology of the pathogens on dairy farms. For this cohort study, fecal samples were collected from 276 clinically ill calves across 5 central Ohio dairy farms on the first day of diarrheal diagnosis. Genomic techniques, including reverse transcription polymerase chain reaction (RT-PCR) and droplet digital polymerase chain reaction (ddPCR) were used to test for the presence of the five enteric pathogens. A Poisson regression model was used to estimate the relative risk of mortality, and a survival analysis with a Cox regression model was used to analyze time to return to a healthy clinical status by pathogen. Rotavirus was the most frequently identified at 68.1 % (188/276), followed by F5 (K99)E. coli at 42.5 % (114/268), C. parvum at 28.4 % (66/232), coronavirus at 5.8 % (16/276), and Salmonella had the lowest prevalence at 3.7 % (10/268). Risk of mortality tended to be higher for calves infected with Salmonella (RR = 3.83; 95 %CI: 0.93, 16.02, p = 0.062); however, the time to return to a healthy clinical status was not different for different pathogens. Only farm was a significant predictor of time to return to health (p = 0.017); the within-farm median duration of signs substantially varied between 2 and 7 days. The results suggest that the prevalence and distribution of rotaviral infections is higher than reported in prior studies. With the exception of infections caused by Salmonella spp., pathogen diagnosis on the first day of diarrhea was a poor predictor of the outcome and duration of disease. These results are critical to guide the implementation of prevention measures to detect, treat, and prevent calf diarrhea.
犊牛胃肠道疾病仍然是奶牛养殖场生产力和经济损失的主要原因之一。大多数未断奶犊牛的死亡归因于腹泻或其他消化问题。有五种肠病原体通常与奶牛犊牛腹泻有关，包括牛轮状病毒、牛冠状病毒、大肠杆菌、沙门氏菌和小隐孢子虫。与健康结果和病死率相关的病原体差异尚未得到很好的描述。此外，更新的流行率估计可能反映了奶牛场病原体流行病学的重要变化。在这项队列研究中，从俄亥俄州中部 5 个奶牛场的 276 头临床患病犊牛中采集了粪便样本，这些犊牛在腹泻诊断的第一天采集。采用逆转录聚合酶链反应（RT-PCR）和液滴数字聚合酶链反应（ddPCR）等基因组技术检测五种肠病原体的存在。采用泊松回归模型估计死亡率的相对风险，并采用 Cox 回归模型进行生存分析，按病原体分析恢复健康临床状态的时间。轮状病毒的检出率最高，为 68.1%（188/276），其次是 F5（K99）大肠杆菌，为 42.5%（114/268），小隐孢子虫为 28.4%（66/232），冠状病毒为 5.8%（16/276），沙门氏菌的检出率最低，为 3.7%（10/268）。感染沙门氏菌的犊牛死亡风险较高（RR=3.83；95%CI：0.93,16.02，p=0.062）；然而，不同病原体之间恢复健康临床状态的时间没有差异。只有农场是恢复健康时间的显著预测因子（p=0.017）；农场内的症状持续中位时间在 2 至 7 天之间变化很大。结果表明，轮状病毒感染的流行率和分布高于之前研究报告的水平。除了由沙门氏菌引起的感染外，腹泻第一天的病原体诊断对结果和疾病持续时间的预测不佳。这些结果对于指导实施预防措施以检测、治疗和预防犊牛腹泻至关重要。
