Nasal discharge is an excess of fluid material from the nasal cavity. Nasal discharges can originate from either the respiratory or gastrointestinal tracts. However excessive or abnormal discharge is usually an indication of upper respiratory tract disease.
Sheep breeds with convex facial profiles such as Suffolk and Border Leicester are reputedly more susceptible.
Nasal discharge is detected during pen inspection. Discharges may be serous (thin, clear and colourless), catarrhal (grey, flocculent) purulent (thick, yellow), or haemorrhagic (red). A discharge may change in colour and consistency over time depending on the progression of underlying disease. Colour, consistency and content will often reveal the source. Presence of food or stomach content indicates obstruction of the oesophagus or gastrointestinal tract, respectively - generally accompanied by distress and severe systemic signs. Unilateral discharges indicate localized conditions involving the nose or sinuses whereas bilateral discharges may indicate thoracic or systemic conditions.
The most likely differential diagnoses in shipboard cattle with nasal discharge include:
In sheep and goats common causes of discharge in multiple animals include nasal bots, dusty feed, ammonia vapor, fly worry and upper respiratory tract infections due to viruses or bacteria. Fly worry will occur on land, and other causes may occur at all stages of the export process. When single animals are affected, differential diagnoses may include tumours, foreign bodies and facial trauma distorting the nasal passages.
Differentiation may be assisted by presence of other signs such as sneezing, coughing, eye discharges, attempts to hide the face and whether the discharge is unilateral or bilateral. Unilateral discharge usually indicates local involvement of one nasal passage. Bilateral discharge may indicate systemic disease affecting the upper respiratory tract. Close examination for presence of mucus, pus, blood or foreign material may offer clues.
Choice of treatment is dictated by the diagnosis.
If infectious respiratory disease is suspected then administration of parenteral antibiotics (ceftiofur sodium, florfenicol, tilmicosin, tulathromycin, procaine penicillin, oxytetracycline, erythromycin, or tylosin) is warranted.
With dusty feed, the problem may be related to a batch of feed which when changed, resolves the problem.
With reduced grooming of the nose, feeding chaff or hay may stimulate appetite and rumen function. The animal will then start licking its nose. Treatment with glucocorticosteroids or other injectables purported to stimulate appetite is not recommended.
Prevention in the live export process relies on careful screening during selection and on controlling flies, dust and ventilation during the export process.
Vaccination of cattle against IBR and Mannheimia haemolytica have been reported to reduce risk of infectious respiratory disease in export consignments.
If dusty feed is suspected, dampening the feed may help but may result in mouldiness and palatability problems. Other preventative measures are determined by hazards and risk factors specific to the consignment.