If your veterinarian has an ultrasound machine, it has tremendous value to your herd beyond diagnosing pregnancies.
Theresa Ollivett, Assistant Professor in the Food Animal Production Medicine Section, School of Veterinary Medicine at the University of Wisconsin-Madison, has become a pioneer in using thoracic (lung) ultrasounds to manage the healthy development of dairy calves.
Ollivett recently shared her knowledge of lung ultrasounds via webinar with the Dairy Girl Network. She said trained veterinarians can perform lung ultrasounds in less than one minute per calf with about 88% diagnosis accuracy. Comparatively, clinical evaluation has about 60% accuracy, and listening to lungs with a stethoscope has just 10% accuracy.
“It’s interesting to note that severity of lung disease is not well-coordinated with clinical signs in calves,” she said. “About a third of all new cases of pneumonia are subclinical, meaning they only can be detected via ultrasound. And there are 2 to 4 subclinical cases for every clinical case of pneumonia we diagnose.”
Also, calves that appear to have pneumonia actually may be struggling with another condition. Ollivett said she is seeing a rising incidence of Salmonella in calves, many of whom may appear to have pneumonia, but actually have fairly healthy lungs. That differentiation only can be achieved via ultrasound.
Ollivett utilizes lung ultrasound in conjunction with the University of Wisconsin Calf Health Scorer, which is available as an app on the I-Tunes App Store. Like the Health Scorer, she utilizes a 0-5 scoring system, with 0 being completely healthy lungs, and 5 being lungs with consolidated tissue in at least three lobes.
“With treatment, calves can return to healthy lung tissue, except in cases in which we detect necrosis or abscesses,” she shared. Ollivett also noted that an antibiotic treatment duration of longer than three days may be necessary to achieve a complete cure, which she has learned by using lung ultrasound to evaluate long-term treatment outcomes.
While it’s probably not practical to have your veterinarian ultrasound every calf in your herd, Ollivett noted several practical applications of the technology, including:
- Monitoring outcome of treatment of clinical cases. In other words, have your veterinarian check calves you have treated based on clinical signs.
- Checking newborn calves at less than a week old for improper tube feeding, which can cause aspiration pneumonia. At this age, 80% or more of calves should display healthy lungs.
- Evaluating a subset of calves on a continuum to determine at which age, if any, pneumonia cases spike. Identifying that stage can help pinpoint necessary management changes.
- Making culling decisions if a herd has excess heifers.
- Investigating poor growth performance.
- Evaluating the success of an intervention, such as installing ventilation tubing, or changing a vaccine protocol.
- Screening purchased animals.
Ollivett noted that the impact of pneumonia on future herd replacements cannot be underestimated. “Pneumonia – whether clinical or subclinical – can impede growth and make calves less capable of responding to vaccines and antibiotics,” she said. “Long-term data evaluation also shows that any heifer calf that has had pneumonia is affected for life. She is more likely to die or be removed from the herd before her first calving; have lower pregnancy rates; and produce an average of 1,200 pounds less milk in her first lactation – even if she responds well to treatment.”
Consult your herd veterinarian on how lung ultrasound could be routinely incorporated into your health program. One note of caution: if lung ultrasounds are performed on regular herd-health days, be sure your veterinarian performs them first, before working with older animals.
To read more advice and updates on lung ultrasound from Ollivett, you can follow her “Lung Ultrasound and Bovine Respiratory Disease” Facebook page here.