“If you don’t use lung ultrasound, you won’t catch a lot of pneumonia cases,” says Sebastián Umaña Sedó, assistant professor of production management medicine, VA-MD College of Veterinary Medicine at Virginia Tech.
That statement reflects a growing reality in calf health, and it is backed by field data.
In a new multistate dataset presented by Umaña Sedó of 357 dairy calves across 34 farms in Virginia, Pennsylvania and North Carolina, roughly 30% of calves showed some form of respiratory disease between 22 and 60 days of age. Clinical pneumonia and subclinical pneumonia occurred at nearly identical rates, each accounting for about 10% to 11% of cases.
This is a substantial portion of pneumonia occurring in calves that would appear normal during routine observation.
Why Health Scoring Alone Isn’t Enough
Subclinical pneumonia often goes undetected because calves can appear healthy despite significant lung lesions. Standard respiratory scoring systems remain useful, but they have a critical blind spot.
“Clinical pneumonia is when we have a positive health score and positive ultrasound … subclinical pneumonia is when the health score is negative but the ultrasound is positive,” Umaña Sedó says, emphasizing that ultrasound is essential to identify subclinical cases. Calves can pass a health exam and still have meaningful lung pathology.
“If you do a health score on one calf, you might say the calf is healthy, but in reality it has a compromised lung. So there can be a disassociation between what you see clinically and what is actually happening in the lung,” he explains.
This gap between appearance and pathology allows disease to progress unnoticed, often until treatment becomes more difficult and more costly.
The Real Cost of Delayed Detection
Missed or late-detected pneumonia carries real economic consequences, even when cases are eventually treated.
“A case of pneumonia is around $300, and this is just the first treatment. Most of these animals need two treatments,” Umaña Sedó says.
In addition to direct treatment costs, delayed pneumonia detection is associated with higher retreatment rates, increased antimicrobial use and reduced growth and future productivity. At the same time, subclinical cases may go undetected entirely, quietly impacting performance without ever being formally diagnosed.
What Thoracic Ultrasound Changes
Thoracic ultrasound addresses this gap by allowing veterinarians to assess the lung directly rather than relying solely on outward signs.
“It really helped to change the health of these calves by detecting pneumonia way earlier,” Umaña Sedó says.
With ultrasound, practitioners can:
- Detect lung consolidation earlier
- Differentiate upper versus lower respiratory disease
- Identify cases that actually require antimicrobial treatment
- Monitor response to therapy
This shift enables earlier, more precise and more confident intervention.
Set Ultrasound Benchmarks
As adoption increases, thoracic ultrasound is moving beyond diagnosis and becoming a tool for herd-level monitoring and decision-making.
Umaña Sedó highlights practical Wean Clean benchmarks set forth by The Dairyland Initiative at the University of Wisconsin-Madison that farms can use to evaluate their respiratory programs:
- At the start of weaning: Fewer than 15% of calves should have evidence of pneumonia
- At first treatment: Fewer than 15% of calves should have advanced lung lesions (score greater than 3)
→ Higher levels suggest disease is being detected too late - 7 to 10 days after treatment: Fewer than 15% of calves should still show significant lesions (score greater than 2)
→ Higher levels may indicate treatment failure or relapse
Together, these benchmarks provide a way to evaluate both timing and effectiveness of intervention.
How to Start Using Ultrasound On-Farm
For many operations, implementation begins with a simple, targeted approach.
“The way I started with this was scanning animals that were not getting better … and then showing the producer what we were finding and how treatment could change based on that,” Umaña Sedó explains.
That initial step helps demonstrate value quickly and builds confidence in the tool.
“You start with a few animals, and as you get results, you can expand — scan 10 to 12 calves every week and follow them through weaning,” he suggests.
One structured approach is the 12 × 7 strategy, which involves beginning scans at seven days of age, evaluating a group of 12 calves and repeating that process every seven days. Over time, this helps identify when calves are most at risk and supports more proactive management.
From Better Decisions to Proactive Care
Thoracic ultrasound is not only improving how pneumonia is detected; it is also reshaping how treatment decisions are made.
“Right now, we’re treating some of those cases with anti-inflammatories instead of antimicrobials, because we’re scanning constantly and we have that data,” Umaña Sedó says.
By distinguishing true pneumonia from upper respiratory disease, ultrasound allows for more targeted antimicrobial use, reduces unnecessary treatments and better aligns calf health programs with antimicrobial stewardship goals.
More broadly, thoracic ultrasound reflects a shift in how calf respiratory disease is managed. Instead of reacting to visible illness, veterinarians can detect disease earlier, better understand its true prevalence within a herd and continuously refine treatment protocols based on real data.
In doing so, they are not just improving detection, but redefining what effective pneumonia management looks like.
