Hoose is caused by lungworm and is one of the most important respiratory diseases of cattle. The signs of infection include coughing and difficulty in breathing, especially when exercised. It can result in death without warning where serious infections occur. It is mainly seen from midsummer onwards.
Larvae on pasture are picked up while grazing and make their way to the lungs where they rapidly mature and start laying eggs. These eggs are coughed up and swallowed and incubate in the gut, then are passed out to rapidly again become infective. The whole process takes about 24 days. Larvae can survive over winter on pasture and also be carried by older animals.