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Screening for respiratory disease in dairy calves

Theresa L. Ollivett Published on 27 February 2015

It is probably safe to say that respiratory disease in dairy calves (BRD) is an all-too-familiar problem for dairy producers. During late fall and early spring, fluctuating weather is a challenge and typically increases the number of calves treated for BRD.

Failure of passive transfer, scours, commingling and stress from certain management events also increase disease, regardless of the time of year. Controlling these variables is necessary for keeping the level of BRD as low as possible.

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Timely detection and treatment are equally critical for controlling BRD. Early treatment is more effective and results in fewer chronic cases of disease. Chronic cases are most concerning because of poor growth, increased mortality and the spread of disease to other calves.

Since sick calves often do not stand out from the crowd, screening all calves that might become sick will improve detection rates. There are at least five requirements for effective screening for BRD:

1. Competent, dedicated personnel

2. A defined screening exam

3. Posted treatment protocols

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4. Permanent place to record findings and treatments

5. Oversight of records

Personnel responsible for BRD screening should be competent and dedicated. Appropriate training ensures competence and helps the screener understand the purpose of his or her role. As herd size allows, screeners should not work with adult cattle.

This may not be possible in smaller herds, where one person works in multiple management areas. In such situations, precautions such as working with younger animals first, hand-washing, gloves and changing coveralls and boots will help to avoid transmission of disease from older cattle to the younger calves.

Clearly defining the screening exam ensures calves are regularly and consistently examined. Screening the calves most likely to get sick increases the chance a sick calf with subtle signs will be detected early. Additionally, using the same exam over and over will increase the screener’s confidence level and willingness to treat early.

One example of a systematic scoring system that can be implemented by on-farm personnel is the University of Wisconsin Calf Respiratory Score Chart (UW-CRSC), developed by Dr. Sheila McGuirk.

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The UW-CRSC looks for five different abnormalities: fever, cough, nasal discharge, ocular discharge and droopy ears. Each category is scored from zero to 3 points, and a category is considered abnormal if it scores 2 or greater.

Calves are considered sick if there are at least two abnormal categories. Calves scoring a 2 or greater for the ear category are an exception and should be treated for otitis regardless of other signs.

The Food Animal Production Medicine section at the UW – Madison School of Veterinary Medicine has developed an iPad application to aid in the implementation of routine screening (Figure 1). This app will store each calf’s respiratory score and create a list of calves to be treated.

Calf health scorerOther screening systems include the DART system, and more recently, modifications of the UW-CRSC. The DART system (depression, appetite, respiratory, temperature) relies heavily on the presence of depression, inappetence and fever to indicate when treatment is necessary.

Unfortunately, as previously mentioned, these signs are not consistently shown by dairy calves with BRD. The modified UW-CRSCs are intended to reduce handling of calves and can be similarly effective in identifying calves with BRD as the UW-CRSC.

Respiratory scoring, as described above, does not differentiate between upper respiratory tract infections and the more severe cases of pneumonia. If your veterinarian is involved in the screening process, lung ultrasonography can be used to screen specifically for lung lesions, even when the calf does not look sick.

With training, your veterinarian can quickly ultrasound calves using the same portable ultrasound intended for diagnosing pregnancy in adult cattle.

When combined with respiratory scoring, routine ultrasonographic screening provides accurate levels of both upper and lower respiratory tract disease, helps identify animals with irreparable lung damage and helps guide treatment and management decisions.

Work with your veterinarian to make posted, written treatment protocols. In most situations, consistent early treatments using the appropriate dose, duration, frequency and route of an antibiotic are more important than which antibiotic is selected.

The only way to ensure all calves are treated similarly is to post these protocols and train personnel. Stopping treatment protocols early, switching antibiotics and using the wrong dose reduce the likelihood of recovery and increase the costs associated with treatment.

Results from all screening and treatments for BRD should be recorded. Computerized individual calf records are the gold standard; however, Excel spreadsheets and even paper records in a bound notebook can suffice.

Oversight of these records allows you to track increases or decreases in disease, monitor responses to treatment protocols and identify protocol drift. Most importantly, this information can be used to develop prevention strategies.

In addition to screening twice a week, calf personnel should look daily for calves that are depressed, off-feed or isolating themselves from others within the group. These calves should be thoroughly examined and treated according to protocol.

Lastly, work with your veterinarian to define an end point for treatment. This prevents prolonged treatment of hopeless cases, identifies animals for treatment at specialty hospitals if desired and avoids endangering the welfare of severely affected calves.

In summary, trained personnel, a systematic screening exam, written treatment protocols, disease recording and oversight of health records are key factors for early detection and treatment of BRD. Incorporating these elements into your calf management program will help reduce the impact of BRD on your dairy calves.  PD

This article was originally written by the author for Agri-Plastics.

Theresa L. Ollivett
  • Theresa L. Ollivett
  • Assistant Professor Food Animal Production Medicine
  • University of Wisconsin – Madison

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