Bovine Respiratory Disease (BRD)

- Clinical signs of BRD and clinical respiratory scores of BRD

· Abnormal behaviors such as depression, lowered head position, head tilt,

· Dyspnea, ocular or nasal discharge,

· Fever and anorexia.

· Many of the clinical signs observed with BRD may also be present with other diseases such as septicemia or gastrointestinal disease.

· Scoring system and definitions of BRD in calves (McGuirk and Peek,2014) .

Parameter	Score
Parameter	0	1	2	3
Rectal temperature (°C)	37.5–38.2	38.3–38.8	38.9–39.4	≥39.5
Cough	none	induced-single	induced and spontaneous single (2–3)	spontaneous repeated (>3)
Nasal discharge	serous	small amount, unilateral, cloudy	bilateral, mucus	bilateral, mucopurulent
Head and ear position	normal	ear flick/head shake	slight unilateral ear drop	severe head tilt, or bilateral ear drop
Ocular discharge	none	small	moderate	severe

· All calves with a rectal temperature ≥39.5 °C and at least one parameter ≥2 were defined as ‘at risk’ for BRD

· Calves were only defined as diseased (DIS) if the rectal temperature ≥39.5 °C and at least one parameter ≥2 were present for two consecutive days.