Table 9.

ABMs of respiratory disorders in individual pens in dairy farms

ABM	Comments
Rectal Temperature	Definition: Rectal temperature above 39.7°C is considered a sign of infection. Sensitivity: High. Sensitivity of high rectal temperature to diagnose respiratory disease is considered to be high in acute cases. Specificity: Low. Other health disorders in calves of the same age may result in high temperature.
Respiratory sounds at lung auscultation*	Definition: Increased respiratory sounds at lung auscultation. Sensitivity: Low. Upper respiratory disease may not always cause increased respiratory sounds Specificity: High.
Coughing*	Definition: Brisk expel of air from the lungs by sudden contraction of the diaphragm and intercostal muscles in response to irritation of the lower respiratory tract. Sensitivity: High in acute cases of BRD. Specificity: High.
Nasal discharge*	Definition: Clearly visible flow from the nostril. Can be transparent, yellow or green (Welfare quality® protocol cattle). Upper and lower respiratory tract infection will cause an increase in mucous or purulent discharge. Sensitivity: Low. Animals with respiratory disease do not always show nasal discharge. Specificity: High.
Ocular discharge*	Definition: Usually bilateral mucous or purulent discharge, because some BRD infectious agents will also cause conjunctivitis. Sensitivity: High. Specificity: Low. Also seen in eye diseases and in dusty environments.
Droopy ears*	Definition: Droopy and sometimes asymmetrical‐positioned ears (additionally, some of the BRD agents will cause otitis). Sensitivity: Low. Not all calves with respiratory disease will show droopy ears. Specificity: Low. Calves with conditions causing apathy, dullness and poor overall condition can also show droopy ears.

^*ABMs included in scoring systems for detection of bovine respiratory disorders.