A mulitfactorial etiology is assumed with this disease. Concurrent disease, close confinement, poor ventilation and hygiene, vitamin A deficiency and infection with F. necrophorum are all implicated. Mixed upper respiratory infections (IBR, Mycoplasma spp, Pasteurella spp and Haemophilus spp) may exacerbate illness.
This disease primarily presents as acute fever, anorexia, toxemia, coughing, dyspnea and stridor in young cattle. Older cattle, between 3 and 18 months can be affected though less severe signs are evident. Ptyalism, dysphagia, purulent nasal discharge and halitosis may also be present. In severe cases, aspiration pneumonia and permanent distortion of the larynx may ensue.
In calves which are euthanased or have died, postmortem findings are characterised by acute, suppurative andnecrotic laryngitis. In chronic cases, lesions consist of necrotic cartilage associated with a draining tract surrounded by granulation tissue.
Diagnosis is based on presenting clinical signs, postmortem findings, and supportive diagnostic tests.
A range of broad-spectrum antimicrobial drugs have been used to treat this disease, including:
- Sulfonamides, enrofloxacin, ceftiofur or tetracyclines
- Penicillins - e.g. procaine penicillin (22,000 U/kg, IM, bid)
- NSAIDs - e.g. Tolfedine, aspirin or ketoprofen
A tracheostomy is indicated in calves with severe dyspnea.
Prognosis is guarded in severely affected calves.