NEMATODIRUS, IF YOU WAIT, IT COULD BE TOO LATE
Unpredictable weather patterns could result in a high Nematodirosis risk in 2019. This is why it's vital this year, more than ever, to keep checking the Nematodirus forecast.
Nematodirosis is caused by the parasite Nematodirus battus and causes intestinal damage leading to profuse, watery diarrhoea. Nematodirus battus causes disease in young lambs which have never been exposed previously and so have no acquired immunity.
Nematodirus battus is transmitted from the lambs grazing the pasture in the previous season to those grazing in the current season making it particularly difficult to control.
L3 larvae ingested from the pasture develop into adult worms which produce eggs. This takes as little as 14-21 days.
These eggs then pass out in the faeces resulting in greater pasture contamination. These eggs will either go develop into infective larvae which can infect lambs immediately or they will lie dormant until the following Spring when they can infect the new crop of lambs which have no natural immunity.
Thankfully once lambs have been exposed they begin to develop natural immunity however nematodirus is capable of causing a great deal of damage, and even death, before this immunity develops.
WHEN IS THE RISK?
Frustratingly the highest risk period will vary slightly from year to year making it difficult to counteract. There are two significant factors to consider:
1 ENVIRONMENTAL CONDITIONS
If the weather suddenly changes from cold, frosty mornings to mild, warmer spring weather, a mass hatching of parasites on the pasture occurs.
2 LAMB AGE/WEANING
If this mass hatching occurs around the same time that lambs are beginning to consume significant amounts of grass (6-12 weeks) then the risk will be very high.
WHAT OTHER RISKS ARE THERE?
- Grazing lambs on the same pasture which they were grazed on last spring
- Presence of other parasites e.g. coccidiosis
- Other stress, triplets, fostered lambs etc.
- Sudden onset profuse diarrhoea
- Faecal staining of tail and perineum
- Dull/depressed lambs
- Lambs which stop sucking
- Gaunt condition
- Rapid loss of body condition
- Lambs congregating around water to rehydrate
WHY SHOULD I BE WORRIED?
First and foremost - lamb welfare. Secondly the cost of nematodirus is high, 5% of the lamb crop may be lost and the surviving lambs will take longer to finish.
The Department of Agriculture recommend that, if treatment is required, a group 1 (white/1-BZ) wormer should be used. When treating lambs weigh them and dose accurately to ensure that treatment is effective and to help protect anthelmintics from resistance. Faecal worm egg counts 7-10 days after treatment are vital for determining efficacy of the treatment.
A broad spectrum, multi-purpose anthelmintic for the control of mature and developing immature forms of gastro-intestinal roundworms, lungworms, tapeworms and adult liver fluke in sheep and cattle. It is also ovicidal against fluke and roundworm eggs.
*Endospec 2.5% contains albendazole 25 mg, selenium (as sodium selenite) 0.27mg, cobalt (as cobalt sulphate) 0.624mg per ml. The following active ingredients have indications for nematodirus in sheep. Please consult your vet to determine which is most appropriate and consult the SPC data sheet for further information.