By Rick Sibbel, D.V.M.
Merck Animal Health was pleased to co-sponsor the 2014 BRD Symposium, and continues with its series on sharing some of the latest research findings and management techniques from this meeting.
Early intervention in a BRD infection greatly improves treatment outcomes. However, cattle are masters at masking the symptoms, so early detection can be difficult.
At the symposium, Dee Griffin, D.V.M., University of Nebraska–Lincoln, Great Plains Veterinary Educational Center, said that because cattle are prey animals, they are excellent at hiding signs of disease from their caregivers, especially if that person has not gained their trust.
In acute cases, depression, appetite loss and abnormal respiration are used to identify BRD, with rectal temperature used to estimate severity of the illness. Rectal temperatures of 104° F to 105° F are used to signal BRD infection and treatment, but cattle with subclinical BRD can have rectal temperatures below the low-end cut-off. Dr. Griffin pointed out something that’s important to remember: “Don’t let a thermometer do your thinking.”
Teaching caregivers to use a stethoscope to evaluate the anterior ventral lung area can be a good addition to a thermometer when evaluating cattle pulled for suspected BRD.
He said lung assessments for anterior ventral (AV) lesions at the packing plant often reveal higher BRD incidence than observed in the feedlot, suggesting subclinical BRD is common. Consequently, scoring lungs gives us more insight into true BRD incidence. Fortunately, there is a lung scoring systemI with three lesion classifications that can be applied in the plant at chain speed.
More accurately identifying BRD infections is not only important for the animal’s health and well-being, but studies show that on average, subclinical BRD reduces average daily gain (ADG) by 0.20 lbs. and drops the USDA Quality Grade by 50 marbling points.
Financially, what does this mean? In Dr. Griffin’s example, a 20 percent subclinical BRD rate deducts $19.44 from every finished animal due to lower weight gain and carcass value. As the value of cattle increase this underestimates the loss in today’s market.
¹ Bryant L.K. (1997). Thesis: Lung lesions in feedlot aged beef calves at slaughter: an observational study to develop methodologies for recording lung lesions at slaughter and investigating their associations with production. P. 1-116. Great Plains Veterinary Educational Center, University of Nebraska-Lincoln, Lincoln, Nebraska.
You can get this presentation or order a copy of the 2014 BRD Proceedings at http://brdsymposium.org/.