Use of fever detection in combination with thoracic ultrasonography to identify respiratory disease, and compare treatments of antimicrobials and NSAID: a randomised study in dairy calves.
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引用次数: 3
Abstract
Background: This study explored the combined use of fever detection and thoracic ultrasonography to identify calves with early onset bovine respiratory disease (BRD). Thoracic ultrasonography was then used to assess the efficacy of antimicrobial and non-steroidal anti-inflammatory drug (NSAID) treatment for early onset BRD through a randomised study design.
Methods: Calves were recruited from a single dairy farm in the UK, and fitted with a TempVerified FeverTag, which was activated when a calf developed fever (a temperature of 39.7°C for six hours). On identification of fever, a Wisconsin calf score was used to provide a diagnosis of BRD by exclusion of other causes. Calves were randomly assigned to experimental groups; group 1 (NSAID) received flunixin meglumine, group 2 (antimicrobial) received florfenicol, group 3 (both) received both drugs. A thoracic ultrasound was conducted within 48 hours of fever detection, and again 14 days later to assess lung pathology.
Results: A total of 152 calves were recruited, with a relative BRD prevalence of 49 per cent (74/152). Thirty-two calves required a secondary treatment (due to continued fever), causing exclusion from statistical analysis of the change in ultrasound score and resulting in the study being underpowered for detecting statistical significance. Initial thoracic ultrasound scores were very low, with 70/74 calves scoring either 0 or 1, indicating few comet tails and no lung consolidation was seen and potential overdiagnosis of BRD. For assessment of therapy efficacy, no effect of experimental group was detected on average daily growth rates (mean 0.85 kg/day, P=0.89). Calves also displayed very few clinical signs at the time of fever detection. These factors combined suggest a high rate of false positive identification (low specificity) for BRD through fever detection alone. Calves given the NSAID only were more likely to require repeat treatments due to fever recurrence (OR=3.10 (95 per cent CI 0.86 to 11.15), P=0.083). Also calves affected by their first case of fever at an older age (21 v 28 days old) were less likely to go on to have further fever episodes (OR=0.95 (95 per cent CI 0.90 to 0.99), P=0.026).
Conclusion: This study demonstrated calves given only an NSAID at occurrence of fever due to BRD may be more likely to require repeat treatments throughout the preweaning period. The use of fever detection alone for BRD indicated a low specificity for definitive diagnosis as shown by the low thoracic ultrasound scores and lack of clinical signs. The study was underpowered to assess the ultrasonic effects of the different treatment protocols on lung pathology.
背景:本研究探讨了结合发热检测和胸部超声检查来识别犊牛早发性牛呼吸道疾病(BRD)。然后通过随机研究设计,使用胸部超声检查评估抗菌和非甾体抗炎药(NSAID)治疗早发性BRD的疗效。方法:从英国的一个奶牛场招募小牛,并安装了温度验证发烧标签,当小牛发烧时(温度为39.7°C,持续6小时),该标签就会被激活。在确定发烧,威斯康星小牛评分被用来提供诊断BRD排除其他原因。将犊牛随机分为试验组;组1(非甾体抗炎药组)给予氟尼新大聚胺,组2(抗菌药物组)给予氟苯尼考,组3(两组)同时给予两种药物。48小时内进行胸部超声检查,14天后再次进行肺部病理检查。结果:总共招募了152头小牛,相对BRD患病率为49%(74/152)。32头小牛需要二次治疗(由于持续发烧),导致超声评分变化的统计分析被排除在外,导致研究在检测统计意义方面的能力不足。最初的胸部超声评分很低,70/74的小牛得分为0或1,表明很少有彗星尾,未见肺实变,可能过度诊断BRD。在评估治疗效果时,实验组对平均日生长率无影响(平均0.85 kg/day, P=0.89)。小牛在发热检测时也表现出很少的临床症状。这些因素综合起来表明,仅通过发热检测,BRD的假阳性鉴定率很高(特异性低)。仅给予非甾体抗炎药的小牛更有可能因发烧复发而需要重复治疗(OR=3.10 (95% CI 0.86至11.15),P=0.083)。此外,犊牛在较大年龄(21日龄或28日龄)出现首次发热的可能性较小(OR=0.95 (95% CI 0.90至0.99),P=0.026)。结论:本研究表明,在BRD引起发烧时仅给予非甾体抗炎药的犊牛更有可能在整个断奶前需要重复治疗。单独使用发热检测BRD表明明确诊断的特异性较低,这体现在胸部超声评分较低和缺乏临床体征。该研究不足以评估不同治疗方案对肺部病理的超声影响。
期刊介绍:
Veterinary Record Open is a journal dedicated to publishing specialist veterinary research across a range of topic areas including those of a more niche and specialist nature to that considered in the weekly Vet Record. Research from all disciplines of veterinary interest will be considered. It is an Open Access journal of the British Veterinary Association.