The incidence of lungworm disease in Ireland continues to rise, potentially costing farmers significant losses. The combination of mild winters and variable rainfall increases infection risks. Unfortunately for farmers, what is usually seen as good grass growth weather is also the optimal conditions for parasites. The grass growth which is driving the Irish dairy industry is also an influential factor in the increase in lungworm prevalence over the past decade. As farmers learn to maximise pasture, cows are at a higher stocking density in paddocks and are grazing the grass to a lower level. Larvae spread in dung on grazing blocks means that the infection process can repeat over time until there is a sizable outbreak on the farm.
The persistency of this parasite is a big challenge for Irish farmers as larvae can overwinter within faecal paths and carrier animals exist within the herd. An outbreak of lungworm will cause significant financial loss to the farm, up to €159-€167 per cow, through reduced milk yield, mortality, reduced fertility and diagnostic and treatment costs (Holzhauer et al 2011). Animal health and welfare is a concern as lungworm can cause parasitic pneumonia and death. If coughing is detected in a group of cattle at grass and lungworm is suspected, all cattle in the group should be treated with anthelmintic and cattle should be moved to a ‘clean’ pasture to prevent reinfection.
Holzhauer M, van Schaik G, Saatkamp HW, Ploeger HW. Lungworm outbreaks in adult dairy cows: estimating economic losses and lessons to be learned. Vet Rec. 2011 Nov 5;169(19):494. doi: 10.1136/vr.d4736. Epub 2011 Aug 18. PMID: 21856653.