Nematodirus battus

What are the effects of Nematodirus battus?

• Causes diarrhoea, weight loss, dehydration and death
• Usually in lambs eating grass at 6-12 weeks of age
• High-risk lambs are ones challenged concurrently by coccidiosis, newly weaned, triplets or had low colostrum intake
• On pasture grazed by lambs last spring
• Lamb-lamb spread, adults are immune
• A sudden cold snap followed by a warm period causes the eggs to all hatch together after over-wintering on the pasture
• The faecal egg count doesn't rise in a flock sometimes until days-weeks after exposure as it is larval stages causing disease, so a FEC in early spring can be a false negative if clinical signs are being seen
• Acts rapidly and can cause high incidence of lamb mortality

What you can do to avoid Nematodirus affecting your flock:

• Don't graze at-risk lambs on pasture that had lambs on last spring
• Use a white wormer (benzimidazole) and
• Check the SCOPS Nematodirus forecast https://www.scops.org.uk/forecasts/nematodirus-forecast ¹
• Lancashire is currently low risk (as of 27/03/2020)

1. https://www.scops.org.uk/forecasts/nematodirus-for ecast/