Lung ultrasounding is proving to be a valuable diagnostic tool in evaluating the respiratory status of dairy calves.
By Sam Barringer, D.V.M., and Liz Adams, M.S., D.V.M.
Using an ultrasound machine for pregnancy diagnosis has proven to be a valuable tool on many dairies. Not only can a veterinarian confirm if a cow is pregnant, but also if the cow is pregnant with multiple fetuses, as well as the health and sex of the fetus(es). There’s a growing interest in a second use of ultrasound on dairies – lung ultrasounding. It’s proving to be a valuable diagnostic tool in evaluating the respiratory status of dairy calves.
Merck Animal Health is training veterinarians to use lung ultrasounding as a new diagnostic tool for better managing respiratory health in dairy calves.
The ultrasound provides a quick and non-invasive way to view the lungs of the calf. The linear ultrasound probe that most practitioners use for rectal ultrasound fits well between the rib spaces of calves and can penetrate to a depth of up to 13 centimeters. With good animal restraint and practice, the exam takes approximately two minutes for each calf.
When selecting the most appropriate animals for lung ultrasound, consider the following:
• Calves 2 to 6 months of age that have a history of pneumonia treatment,
• Calves that are smaller than their peers,
• Calves that have been through a period of stress, such as shipment, pen movements or comingling of new groups, and
• Groups of calves when assessing the performance of a vaccine or treatment protocol.
Lung ultrasounds shouldn’t be used for diagnosing acutely sick pneumonia calves. Decisions on which calves to treat for pneumonia should still be based on physical exams.
What can be learned from lung ultrasounding?
The purpose of ultrasounding lungs is to look for evidence of previous pneumonia – typically one week, one month or longer after the illness – and to identify continued signs of respiratory disease. More specifically, there are three key areas of benefit.
1. Lung ultrasounding allows calves to be identified that will have sub-optimal performance. It has always been presumed that once a calf got broncho pneumonia and lung tissue was impaired that the lesion lasted a lifetime. Emerging evidence from lung ultrasounding has shown that we need to rethink that paradigm. In fact, some lesions appear to resolve. However, in the process of resolution, the impaired lung capacity will lead to decreased performance.
2. Another benefit off lung ultrasounding relates to the rise in genomic testing of animals. If technology is being used to select for genomically superior animals, it is intuitive that any calf prior to selection should have a clean lung field to even qualify for genomic testing. Is it prudent to have a genetic score yet not have the lung capacity to perform?
3. Lung ultrasounding also can be used to assess population medicine interventions. The information gathered on groups of calves is being used to assess vaccine and treatment protocols, facilities, management and employee training. Lung ultrasounding allows us to more precisely measure and manage respiratory disease and its long-term effects.
There are likely additional uses for the data generated from lung ultrasounding. It is an easy noninvasive rapid diagnostic technique using equipment that most veterinarians already have on their truck. As research continues, lung ultrasound scores can be a predictor of productivity and longevity of a dairy cow and perhaps even a predictor of average daily gain or feed conversion in steers sent to the feedyard.
Respiratory disease has been a challenge to the dairy industry for decades. With lung ultrasound, we can now see the impact of our vaccinations, treatments and management changes, so we can move forward with strategies to prevent and minimize pneumonia. On individual animals and groups of animals as a whole, lung ultrasound provides the producer with more information to make informed decisions for the future of his operation.
Merck Animal Health is training veterinarians to use lung ultrasounding as a new diagnostic tool for better managing respiratory health. Contact your veterinarian or your Merck Animal Health representative for more information.
Dr. Sam Barringer is a technical services manager for Merck Animal Health and specializes in calf health management, population medicine and vaccinology. He lives in Colorado Springs, Colo., and can be contacted at firstname.lastname@example.org.
Dr. Liz Adams is a graduate of the University of California, Davis and practices in Central Valley California. Her areas of interest include calf health, utilizing new technologies on-farm and the Jersey cattle breed. She can be reached at email@example.com.