Calf Lung Ultrasounding – A new tool for sub-clinical pneumonia diagnosis

Pneumonia is one of the most significant diseases affecting calves. Often, by the time outward pneumonia symptoms, such as snotty nose and coughing, can be seen by producers, lung damage has already occurred. This can make treating pneumonia more challenging, and the calf may have residual lung damage for the rest of its life. Thoracic ultrasound  is one new tool that can help veterinarians diagnose sub-clinical pneumonia early before significant lung damage occurs.

The main goal of performing thoracic ultrasound is to wean calves with clear, healthy lungs. Calves with minimal lung damage are better able to maintain growth during the weaning period and will be less likely to need antibiotics to treat respiratory disease following weaning. Your veterinarian can ultrasound calves at four distinct time points to evaluate your current diagnostic and treatment strategy. Upon scanning, each calf is given a lung score from 0-5 to indicate the severity of lung changes. This scoring system was developed by Dr. Olivett at the University of Wisconsin and is used in both practice and research. A score of 0 indicates no lung damage, scores of 1 and 2 indicate minor lung damage, and scores of 3, 4, and 5 indicate significant lung damage affecting entire or multiple lobes. Damage is most commonly seen in the ventral portion of the lungs, and most initial lung damage occurs in the right cranial cranial lobe. To begin, your veterinarian can scan 12 calves in seven-day age intervals to evaluate which age group has the highest risk of pneumonia. From there, using the farm’s treatment records, they can scan all calves following their first antibiotic treatment. Then, a scan can be performed again at 7-10 days post-antibiotic treatment to assess treatment efficacy. The final group to be evaluated is weaning-age animals. Weaning age animals with lung changes may need to be managed differently than clean animals.

At each point in production, the goal should be for less than 15% of calves to have significant lung changes. If too many calves have damaged lungs at weaning, it could be because they were not treated, not treated correctly, or they have poor innate immunity, leading to treatment failure. If too many calves have normal or very high lung scores at time of first treatment, workers could be missing the first signs of clinical disease, not spending enough time evaluating the right calves, or other diseases such as sepsis or acidosis are showing up as pneumonia.

If many calves have high lung scores after the first treatment, it could be due to using the wrong antibiotic or using the right antibiotic in the wrong way. Your veterinarian should be able to use the results of a lung ultrasound to make any necessary changes to your evaluation and treatment protocols. They can train workers to be better at assessing calves for symptoms of clinical pneumonia, and they can train workers to give the right antibiotic based on what they see.

Evaluating all these calves takes time. If you want your veterinarian to perform lung ultrasounds, let them know what time of day works best when they can avoid interrupting the flow of chores. Ultrasounding often requires 2-3 minutes per calf, depending on the individual calf’s cooperativeness and the housing layout. It is much easier for the veterinarian if the calves are housed individually in a barn, but scanning can be done in hutches or in group housing. If you plan to ultrasound larger calves, a chute system is necessary for safety and efficiency. Weaning calves with minimal or no lung damage will lead to a better-growing calf and a more productive adult cow. By working together and using diagnostic, prevention, and treatment tools, including lung ultrasound, we can improve animal welfare and increase productivity in the herd.