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Interpretive Summary: Growth performance and hematological changes of weaned beef calves diagnosed with respiratory disease using respiratory scoring and thoracic ultrasonography

By Anne Zinn

A study recently published in the Journal of Animal Science investigated the effect of clinical bovine respiratory disease (BRD) and associated lung consolidations on growth performance and hematological profiles of recently weaned beef calves, as well as the relationship between clinical respiratory signs and lung consolidation detected by thoracic ultrasonography.

BRD is a complicated, multifactorial syndrome that can cause substantial economic losses due to decreased animal performance, mortality rates, and increased cost associated with treatments. It is the most prevalent disease of recently weaned feedlot cattle internationally. Despite the existence of numerous tools, such as clinical respiratory scoring systems and automated monitoring systems of behavior, its diagnosis remains a challenge due to the lack of a “gold standard” diagnostic method. Currently, thoracic ultrasonography is being used as a rapid, noninvasive, and on-site diagnostic and prognostic tool for finding lung abnormalities.  Few studies have researched the relationship between clinical respiratory signs and lung consolidation detected by thoracic ultrasonography or have evaluated the impact of BRD diagnosed using both thoracic ultrasonography and respiratory signs on animal growth performance and hematology, hence the need for the current study. 

Results demonstrated that a greater number of BRD-affected calves were detected using thoracic ultrasonography and clinical respiratory score when compared with just clinical respiratory score alone. Results also indicate that the current detection of BRD in feedlots through clinical respiratory score alone may lead to calves going undetected with lung consolidation due to the weak correlation between clinical signs and lung consolidation. Therefore, thoracic ultrasonography could be implemented in feedlots to detect BRD-associated lung consolidation during the first weeks post-entry, when animals are at greater risk of developing BRD. Further research is required and should focus on the evolution of lung consolidation after therapy and its effect on growth performance as well as exploiting the recent advances in sequencing technologies to characterize the microbiome and virome associated with the development of BRD in this cattle population.

The full paper can be found on the Journal of Animal Science website.