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Lungworm in Cattle

Hoose or lungworm infection, can be widespread and infection this year may be more severe with the heavy rain that followed the long dry spell. Drystock Specialist Martina Harrington has advice on the identification, management and treatment of the disease.

Lungworm infection or hoose is one of the most important respiratory diseases of cattle in Ireland. Outbreaks can be widespread and unpredictable resulting in reduced animal performance and in severe cases animal losses. Infection can also be more severe when a long dry period is followed by heavy rain which leads to a large hatch, this is particularly relevant now. 

It is caused by a parasitic larvae ingested by animals off grass and is most commonly seen in the second half of the grazing season, when large numbers of lungworm larvae have built up on pastures. Young dairy bred calves and autumn born suckler calves are in the biggest danger bracket as they are eating more grass than spring suckler calves on milk plus they have little or no resistance. It becomes more important later in the season in spring born calves as they consume more grass. Lungworm can also be seen in older cattle who have failed to develop or maintain immunity in the first grazing season.

Clinical signs of disease include

  • Intermittent coughing particularly after moving stock.
  • Moderately affected animals will have coughing bouts even when they are resting and may show signs of increased difficulty in breathing.
  • Heavily affected animals suffering from respiratory disease have an increased breathing rate accompanied with opened mouth breathing with head and neck outstretched. The tongue will also appear as they try to cough. The cough will be the harsh deep ‘husk’ cough. Cattle can lose condition rapidly.
  • The nature and severity of lungworm infection depends on the number of larvae that are present.

Always be looking for signs of animals coughing, this is key!

The three major groups of anthelmintics are all effective against lungworm. If coughing is detected in a group of cattle at grass and hoose is suspected, all cattle in the group should be dosed. Cattle should be moved to a ‘clean’ pasture or an anthelmintic with persistent action may be used to prevent re infection.

Calves that were heavily infected need to be closely observed in the 1-2 days post treatment.

Dung sampling is not relevant in the case of lungworm as by the time eggs reach the dung, the damage is already done.

As a word of caution care needs to be taken when using long acting anthelminthics in the 1st grazing season because you may limit the animals exposure to lungworm larvae and cattle will remain susceptible to reinfection the following season due to not developing natural resistance.

Further information on lungworm is available in the AHI leaflet at the link below and always talk to your vet