Pulmonary Ultrasound in the Diagnosis of Respiratory Disease in Dairy Calves - Systematic Review / Ultrassonografia Pulmonar no Diagnóstico de Doença Respiratória em Bezerras Leiteiras- Revisão Sistemática

Bovine respiratory disease (BRD) is a common health challenge for dairy calves during the first weeks of life. It can be caused by several environmental factors and pathogens, such as bacteria and viruses, presenting alterations called pulmonary consolidations. BRD shows nonspecific clinical signs, a high rate of subclinical cases and triggers several health consequences, such as impaired growth, reduced weight gain, interference in production and reproduction during the first lactation, and in some cases, animals can also die. In addition economic losses such as: increase in the rate of involuntary culling and reduction of the source of replacement of productive cows in the herd can also occur. There are some forms of diagnosis evaluating clinical signs such as fever and discharges. However, these methods are not sufficient to confirm the clinical diagnosis and do not allow the measurement of the degree of pulmonary lesions. However, the disease can also be diagnosed by pulmonary ultrasound, presenting a high rate of accuracy.  This study reviews systematically the main studies that performed pulmonary ultrasound evaluation in the diagnosis of BRD and reported results that showed the efficacy of the use of this method in the clinical diagnosis of the disease. The technique is considered noninvasive, fast, capacity of detecting animals with subclinical BRD and uses the same ultrasound device used in the reproductive management of cows. In addition, ultrasonography has other benefits such as cost reduction, reduced use of antimicrobials, evaluation of the extent of lung lesions, positive influence on animal health and support of profitability of a dairy operation.