SHEEP farmers have been advised by the Dept. of Agriculture to be aware of the health risks posed to young lambs and calves by what are known as Nematodirus worms.

These worms – which invade the wall of the intestine leading to severe diarrhoea, illness and even death in severe cases – typically hatch out through the months of March and April.

The Dept. of Agriculture along with Met Éireann can predict the peak times likely to produce surges in the numbers of infected larvae on pastures based on increasing soil temperatures after the colder winter period.

Farmers have been advised by the Department that ‘at-risk’ lambs – six to 12 weeks age group – should be dosed two weeks after the peak of the egg hatching with Benzimidazoles (white drenches) the treatment of choice for the infection.

A tell-tale sign of the disease in young lambs is when they start congregating around water troughs due to the severe thirst that develops – adult sheep are unaffected by the virus.

“This disease is best prevented by keeping the current year’s lambs off any pasture that was grazed by lambs or young calves (which can be carriers of infection) in the previous year. Enterprises with high stocking rates are particularly vulnerable.

“Note that twin lambs, or single lambs born to ewes of poor milking ability may be at a greater risk of developing the disease as they begin consuming greater amounts of grass earlier in life. If ‘clean’ pasture is available, preference should be given to moving these lambs first,” the Dept. advises.

According to the Department’s and Met Éireann data, the peak dates for Nematodirus egg hatching in Galway and Mayo were from April 7 to 10, which means that the best time for dosing would be April 21 to April 24.

However, the Dept. also advise that some farmers may have to make individual decisions to dose earlier where there are clinical signs of the infection.

Pictured: Young lambs are particularly vulnerable to worm or coccidiosis infections.