Use of Thoracic Ultrasonography to Improve Disease Detection in Experimental BRD Infection

Abstract

Bovine respiratory disease (BRD) is caused by complex interactions between viral and bacterial pathogens, host immune status, and environmental stressors. In both clinical and research settings, current methods for detecting BRD in calves commonly focus on visual indicators such as attitude, nasal discharge, and cough, in addition to vital signs such as rectal temperature and respiration rate. Recently, thoracic ultrasonography (TUS) has become more commonly used in clinical settings, in addition to physical examination to diagnose BRD. To assess the value of performing TUS during experimental BRD infection, 32 calves were challenged with bovine respiratory syncytial virus, to mimic a viral infection, and 30 calves were infected with Mannheimia haemolytica, to mimic a bacterial infection. TUS was performed at regular intervals using a standardized method and scoring system in addition to daily clinical scoring. Although overall correlations between clinical scores and TUS scores were generally weak (maximum R2 = 0.3212), TUS identified calves with abnormal lung pathology that would have otherwise been misclassified on the basis of clinical scoring alone, both on arrival and throughout the studies. In addition, TUS had an increased correlation with gross lung pathology on necropsy (maximum R2 = 0.5903), as compared to clinical scoring (maximum R2 = 0.3352). Our results suggest that TUS can provide additional information on calf health at enrollment and throughout a study and may provide an alternative to terminal studies, due to the high correlation with lung pathology at necropsy.

Evaluation of a Respiration Rate Sensor for Recording Tidal Volume in Calves under Field Conditions

“…Furthermore, simultaneous recording of RR and Vt would be possible in a larger number of animals due to less personnel and resource requirements. This non-invasive approach of data recording is also an advantage over other methods of lung examination, such as ultrasound [ 13 , 14 , 15 ] and blood sampling [ 11 , 12 ], where a fixation of the calf is mandatory. The IOS was used as the gold standard because (i) it had previously been thoroughly evaluated for pulmonary function testing in calves, and (ii) it is suitable for the assessment of spirometric parameters of spontaneous breathing.…”

“…Therefore, a lot of research has been published on the study of pulmonary diseases in calves and to diagnose them early [ 7 , 8 , 9 , 10 ]. Besides the analysis of biomarkers in the blood [ 11 , 12 ], also ultrasonic methods [ 13 , 14 , 15 ] and different sensors [ 16 , 17 ] have been tested as diagnostic methods.…”

Comparative diagnoses of respiratory disease in preweaned dairy calves using sequential thoracic ultrasonography and clinical respiratory scoring

“…3,18 Although at the group level cough monitoring holds potential as an early warning sign, clinical assessments such as temperature and behavior have been shown to have a weaker association with lung consolidation on necropsy and to fluctuate throughout disease progression. 19,20 On the other hand, TUS has been shown to be associated with necroscopic lung consolidation based on percentage consolidated. 19,20 Additionally, TUS has been shown to detect lung lesions when clinical signs are not present, potentially providing guidance for early treatment decisions and insight into disease progression.…”

“…19,20 On the other hand, TUS has been shown to be associated with necroscopic lung consolidation based on percentage consolidated. 19,20 Additionally, TUS has been shown to detect lung lesions when clinical signs are not present, potentially providing guidance for early treatment decisions and insight into disease progression. 21,22 In a study using experimental infection with Mannheimia haemolytica, TUS lesions manifested within hours and were present when clinical signs were not, indicating the possibility that TUS may offer earlier diagnosis of BRD.…”

“…TUS has been shown to have a higher sensitivity and specificity than CRS for detecting BRD, although the use of a CRSC is typically considered a faster and simpler method 3,18 . Although at the group level cough monitoring holds potential as an early warning sign, clinical assessments such as temperature and behavior have been shown to have a weaker association with lung consolidation on necropsy and to fluctuate throughout disease progression 19,20 . On the other hand, TUS has been shown to be associated with necroscopic lung consolidation based on percentage consolidated 19,20 .…”