Department of Internal Medicine, Reproduction and Population Medicine, Faculty of Veterinary Medicine, Ghent University, 9820 Merelbeke, Belgium.
Department of Internal Medicine, Reproduction and Population Medicine, Faculty of Veterinary Medicine, Ghent University, 9820 Merelbeke, Belgium; Department of Biomolecular Health Sciences, Faculty of Veterinary Medicine, Utrecht University, 3584 CL Utrecht, the Netherlands.
J Dairy Sci. 2022 Jul;105(7):6111-6124. doi: 10.3168/jds.2021-21570. Epub 2022 May 6.
Bovine respiratory disease (BRD) continues to be a leading cause of economic loss, hampered animal welfare, and intensive antimicrobial use in cattle operations worldwide. Reduction of antimicrobial use is hindered because it is still unclear which clinical signs are best monitored to reliably detect pneumonia. Also, these clinical signs may vary according to age and between breeds. The objective of this cross-sectional study was to identify clinical signs associated with ultrasound-confirmed pneumonia (lung consolidation ≥1 cm depth) pre- and postweaning in different production types (dairy, beef, and veal) and breeds. A total of 956 calves (70% Holstein-Friesian dairy and 30% Belgian Blue beef) from 84 herds were clinically examined using 24 parameters, scored using the Wisconsin and California BRD clinical scoring systems and subjected to thoracic ultrasonography. Of the calves, 42.8% and 19.5% had a lung consolidation ≥1 cm and ≥3 cm, respectively. Cough, both spontaneous and induced, was the only and best-performing clinical sign statistically associated with lung consolidation in all production types. Fever (rectal temperature ≥39.4°C) was the second most promising factor, being significant in beef and veal calves but not in dairy calves. Postweaning, none of the clinical signs studied were statistically associated with pneumonia, with the exception of cough in dairy calves. Spontaneous or induced cough as a single clinical sign outperformed any combination of clinical signs, including the Wisconsin and California respiratory disease scoring systems, but sensitivity remained low. This information can be useful to select appropriate clinical signs for continuous monitoring in precision livestock applications, targeted to a given breed and age. As a cross-sectional measurement, diagnostic accuracy of spontaneous cough (accuracy = 65.1%, sensitivity = 37.4%, specificity = 85.7%) is too low to be used as a criterion to select animals with pneumonia for antimicrobial treatment. At the group level, cough monitoring holds potential as an early warning sign, after which lung ultrasonography should follow.
牛呼吸道疾病（BRD）仍然是导致经济损失、动物福利受损和全球牛群中广泛使用抗生素的主要原因。减少抗生素的使用受到阻碍，因为目前尚不清楚哪些临床症状最适合监测，以可靠地检测肺炎。此外，这些临床症状可能因年龄和品种而异。本横断面研究的目的是确定不同生产类型（奶牛、肉牛和小牛肉）和品种中断奶前后与超声确认肺炎（肺实变≥1 厘米深度）相关的临床症状。从 84 个牛群中共有 956 头小牛（70%荷斯坦-弗里森奶牛和 30%比利时蓝肉牛）接受了 24 个参数的临床检查，使用威斯康星州和加利福尼亚州 BRD 临床评分系统进行评分，并进行了胸部超声检查。在这些小牛中，42.8%和 19.5%分别有肺实变≥1 厘米和≥3 厘米。咳嗽，无论是自发的还是诱发的，是所有生产类型中与肺实变唯一且表现最佳的临床症状。发热（直肠温度≥39.4°C）是第二个最有希望的因素，在肉牛和小牛肉牛中具有重要意义，但在奶牛小牛中则不显著。断奶后，除了奶牛小牛的咳嗽外，没有任何研究中的临床症状与肺炎有统计学上的关联。作为单一的临床症状，自发或诱发的咳嗽优于任何组合的临床症状，包括威斯康星州和加利福尼亚州呼吸疾病评分系统，但敏感性仍然较低。这些信息可用于选择适合特定品种和年龄的精确畜牧业应用中进行连续监测的适当临床症状。作为横断面测量，自发性咳嗽的诊断准确性（准确性=65.1%，敏感性=37.4%，特异性=85.7%）太低，不能作为选择肺炎动物进行抗生素治疗的标准。在群体水平上，咳嗽监测具有作为早期预警信号的潜力，之后应进行肺部超声检查。
