Thoracic ultrasound is a diagnostic tool which can be easily utilized on farm to gain additional information about pulmonary pathology in dairy calves. The purpose of my investigation was to combine Dr Sheila McGuirk's calf respiratory scoring chart, thoracic auscultation, and thoracic ultrasound to evaluate 15 dairy heifer calves.
Calf Respiratory Scoring Chart
The calf respiratory scoring chart was utilized as it is on farm by trained personal – assigning a score for 5 different categories: rectal temperature, cough, nasal discharge, eye scores, and nose score – and adding the numbers to end with a Total Respiratory Score for each calf. Score values of 4 are considered an animal which needs careful observation while scores of 5 or higher requires treatment based off existing farm protocols.
Thoracic Auscultation
Thoracic auscultation has been shown in multiple studies to lack specificity and sensitivity in diagnosing pulmonary pathology but is widely used in dairy calf evaluation. To systematically evaluate the thorax through auscultation, the chest can be divided into 4 quadrants based off those used by Buczinski and her 2014 research “Comparison of Thoracic Auscultation, Clinical Score, and Ultrasonography as Indicators of Bovine Respiratory Disease in Preweaned Dairy Calves.” For my purposes the thoracic was divided as shown below and each quadrant (A, B, C, D) on both the right and left were evaluated for presence of any abnormalities including crackles, wheezes, pleural fiction rub, absence of respiratory noise, or normal.
Thoracic Ultrasound
Ultrasound has been shown to improve specificity and sensitivity in evaluation of pulmonary pathology. Each calf in my investigation was scanned with the BCF ultrasound using a rectal probe and alcohol to flatten the hair. The thoracic images were evaluated for abnormalities including:
One image was obtained from both the right and left as a representative image for each side of the thorax.
Respiratory Score
|
Animal ID |
Birth Date |
Nasal Discharge |
Eye or Ear (highest number) |
Cough – spontaneous or induced |
Temperature |
Total Respiratory Score |
|
4609 |
4-8-17 |
0 |
1 |
0 |
102.0 |
3 |
Thoracic Auscultation
Thoracic Ultrasound
Respiratory Score
|
Animal ID |
Birth Date |
Nasal Discharge |
Eye or Ear (highest number) |
Cough – spontaneous or induced |
Temperature |
Total Respiratory Score |
|
4610 |
4-9-17 |
0 |
2 |
0 |
102.0 |
4 |
Thoracic Auscultation
Thoracic Ultrasound
Right Side – normal pleural surface
Left Side- normal pleural surface
Respiratory Score
|
Animal ID |
Birth Date |
Nasal Discharge |
Eye or Ear (highest number) |
Cough – spontaneous or induced |
Temperature |
Total Respiratory Score |
|
4611 |
4-9-17 |
0 |
0 |
0 |
102.1 |
2 |
Thoracic Auscultation
Thoracic Ultrasound
Right Side – normal pleural surface
Left Side – normal pleural surface
Respiratory Score
|
Animal ID |
Birth Date |
Nasal Discharge |
Eye or Ear (highest number) |
Cough – spontaneous or induced |
Temperature |
Total Respiratory Score |
|
4612 |
4-10-17 |
0 |
0 |
0 |
102.0 |
2 |
Thoracic Auscultation
Thoracic Ultrasound
Respiratory Score
|
Animal ID |
Birth Date |
Nasal Discharge |
Eye or Ear (highest number) |
Cough – spontaneous or induced |
Temperature |
Total Respiratory Score |
|
4613 |
4-10-17 |
0 |
0 |
2 |
102.1 |
2 |
Thoracic Auscultation
Thoracic Ultrasound
Right Side – normal pleural surface
Left Side – normal pleural surface
Respiratory Score
|
Animal ID |
Birth Date |
Nasal Discharge |
Eye or Ear (highest number) |
Cough – spontaneous or induced |
Temperature |
Total Respiratory Score |
|
4614 |
4-11-17 |
0 |
0 |
0 |
102.1 |
2 |
Thoracic Auscultation
Thoracic Ultrasound
Respiratory Score
|
Animal ID |
Birth Date |
Nasal Discharge |
Eye or Ear (highest number) |
Cough – spontaneous or induced |
Temperature |
Total Respiratory Score |
|
4616 |
4-12-17 |
0 |
0 |
0 |
101.5 |
1 |
Thoracic Auscultation
Thoracic Ultrasound
Respiratory Score
|
Animal ID |
Birth Date |
Nasal Discharge |
Eye or Ear (highest number) |
Cough – spontaneous or induced |
Temperature |
Total Respiratory Score |
|
4617 |
4-13-16 |
0 |
0 |
0 |
102.4 |
2 |
Thoracic Auscultation
Thoracic Ultrasound
Respiratory Score
|
Animal ID |
Birth Date |
Nasal Discharge |
Eye or Ear (highest number) |
Cough – spontaneous or induced |
Temperature |
Total Respiratory Score |
|
4618 |
4-13-17 |
0 |
0 |
0 |
102.3 |
2 |
Thoracic Auscultation
Thoracic Ultrasound
Right Side – normal pleural surface
Left Side – normal pleural surface
Respiratory Score
|
Animal ID |
Birth Date |
Nasal Discharge |
Eye or Ear (highest number) |
Cough – spontaneous or induced |
Temperature |
Total Respiratory Score |
|
4619 |
4-14-17 |
0 |
1 |
2 |
102.1 |
5 |
Thoracic Auscultation
Thoracic Ultrasound
Right Side – comet tail and pleural thickening
Left Side – normal pleural surface
Respiratory Score
|
Animal ID |
Birth Date |
Nasal Discharge |
Eye or Ear (highest number) |
Cough – spontaneous or induced |
Temperature |
Total Respiratory Score |
|
4620 |
4-14-17 |
0 |
0 |
0 |
102.4 |
2 |
Thoracic Auscultation
Thoracic Ultrasound
Right Side – normal pleural surface
Left Side – normal pleural surface
Respiratory Score
|
Animal ID |
Birth Date |
Nasal Discharge |
Eye or Ear (highest number) |
Cough – spontaneous or induced |
Temperature |
Total Respiratory Score |
|
4621 |
4-14-17 |
0 |
1 |
0 |
103.1 |
4 |
Thoracic Auscultation
Thoracic Ultrasound
Right Side – comet tail
Left Side – normal pleural surface
Respiratory Score
|
Animal ID |
Birth Date |
Nasal Discharge |
Eye or Ear (highest number) |
Cough – spontaneous or induced |
Temperature |
Total Respiratory Score |
|
4622 |
4-14-17 |
0 |
0 |
0 |
102.7 |
2 |
Thoracic Auscultation
Thoracic Ultrasound
Right Side – comet tail and pleural thickening
Left Side – comet tails
Respiratory Score
|
Animal ID |
Birth Date |
Nasal Discharge |
Eye or Ear (highest number) |
Cough – spontaneous or induced |
Temperature |
Total Respiratory Score |
|
4623 |
4-14-17 |
0 |
0 |
0 |
102.3 |
2 |
Thoracic Auscultation
Thoracic Ultrasound
Right Side – comet tail
Left Side – comet tail
Respiratory Score
|
Animal ID |
Birth Date |
Nasal Discharge |
Eye or Ear (highest number) |
Cough – spontaneous or induced |
Temperature |
Total Respiratory Score |
|
4624 |
4-15-17 |
0 |
0 |
0 |
102.0 |
2 |
Thoracic Auscultation
Thoracic Ultrasound
Right Side – comet tail
Left Side – comet tail
Conclusions:
In my evaluation of this set of heifer calves, clinically they all appeared normal (except for several elevated temperatures, attributed to the extremely hot day). Similar to other studies I found thoracic auscultation to lack a lot of sensitivity and specificity. All the calves auscultated the same despite varying degrees of differences including comet tails and pleural irregularities as my most common findings. This indicates to me the differences in the pulmonary pathology of these calves which is not detectable through auscultation but recognized only with ultrasound imaging.
Through this project, I also found an appreciation for the technique required to image the thorax. Although images are easily obtained, forming quality images for interpretation, as well as understanding clinical relevance requires a little more work. In my experience, liberal amounts of alcohol as well as slightly older calves (larger rib spaces) enabled me to learn the best technique for scanning both sides of the chest efficiently and to produce quality images. As far as clinical relevance, I believe this area requires more investigation. All of these calves clinically appear normal, but still show differences with the ultrasound, in my opinion only time will tell if there are truly production differences in these heifers. Additionally, external factors will affect these heifers throughout their life which may or may not limit their production.
Overall, I find the ultrasound is an efficient way to evaluate the chest and obtain information beyond auscultation and physical appearance. However, long term production outcomes comparing calves with varying pulmonary pathology are still necessary before I’d be willing to make any decisions on the potential consequences of pathology seen in these calves.
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