A very severe disease which affects lambs from the age of 6 weeks to 12 weeks, Nematodirosis is a disease which enters the system through grazing on contaminated pastures.
How it occurs -
Lambs become infected after ingesting large numbers of infective larvae present on contaminated pastures.
The soil contamination is caused by the Nematodirus battus worm. This worm takes approximately 12months for its eggs to hatch, releasing infected larvae into the soils. In Spring when soil temperatures increase after winter, the mass hatching of larvae usually occurs. The main times for the occurrence of the Nematodirus disease is from April to June.
Mortality rates can be high in untreated lambs and after ingestion, Nematodirus larvae invade the intestinal mucosa. The main characteristics of a Nematodirosis infection are diarrhoea, weight loss and severe dehydration. In extreme forms of the infection, death may occur before any signs of diarrhoea can be identified.
Signs - The main signs of an infection, as mentioned, are any signs of diarrhoea, such as a soiled fleece, stained wool and an overall weak state. Other signs include a lack of appetite, weight loss, and weakness.
This disease is best prevented by keeping the current crop of lambs off pastures that were grazed by lambs or young calves last year.
It is also important that farmers are aware that other parasites cause diarrhoea in young lambs also, meaning they will require different control measures and medication. Nematodirus can be wrongly assumed to be the cause of severe diarrhoea in lambs when in fact the cause is a coccidial infection.
This is why seeking advice from a veterinary professional is both vital and can sometimes prove vital in saving an animal’s life. Both nematodirosis and coccidiosis can occur at the same time in the same lambs, so treatment may need to be targeted at both pathogens.
Other methods of prevention include the rotation of pastures and the frequent movement of feeding troughs and watering points to drier areas. This will primarily help prevent coccidiosis in young lambs as localised poaching creates moist conditions suitable for the spread of this parasite.
Raising feeding troughs will also help reduce the contamination of feed with faeces.