30 August 1996

Lamb worm threat

LAMBS that have been grazing dry pasture all summer could now be exposed to a sudden worm challenge after rain in some areas.

Most susceptible will be those six months old which, where its been dry, will have had little previous exposure to infection, says Dr John Vipond of the Scottish Agricultural College.

Heavy rain will release and disperse worm larvae previously locked inside dung pats.

They thatch and migrate up the grass stems ready to infect lambs when eaten.

Dr Vipond warns that worm infection will reduce feed intake and protein absorption – so checking growth.

"It could even cause sudden deaths without scouring," he says. He suggests that, when possible, lambs should be weaned, dosed, and moved on to a clean aftermath.

Previously grazed areas should be reserved for ewes. When no clean grazing is available, lambs must be dosed every three weeks – ideally with a long acting wormer.