High winter temperatures across most parts of the country could impact on parasite infectivity at turnout for both sheep and cattle, according to NADIS.

The statement came as part of the groups March parasite forecast, sponsored by Merial Animal Health, which recommends that farmers plan their parasite control now for this year's grazing season.

In sheep the winters higher than average temparatures indicate a moderate to high risk of chronic liver fluke disease in parts of the UK, with Scotland, North Wales and North West England predicted to experience the highest incidences of disease.

Sioned Timothy, Merial's veterinary advisor, said: "Treating ewes to remove patent, egg-shedding liver fluke infections will help to reduce subsequent fluke challenge to growing lambs later in the year.

“As chronic fluke disease is caused by the adult stage of the liver fluke it is not necessary to use a triclabendazole-based product that targets all stages of the parasite at this time of year.

"Alternative flukicides that target the more mature life stages of the parasite such as, nitroxynil, closantel, albendazole or oxyclozanide may be more appropriate at this time of year.

"Once treated, sheep should be moved to clean pastures.”

“After turnout, young cattle rapidly become infected from overwintered larvae on the pasture.

“Strategically treating youngstock at grass can help prevent parasite burdens from increasing and avoid high levels of pasture contamination later in the grazing season.

"This lessens the risk of parasitic disease and can protect growth rates and overall production.

“Cattle can be treated with an appropriate pour-on or injectable wormer such as those containing ivomectin.

"Cattle treated strategically should remain set-stocked, or moved to safe pastures when these become available.

“I would encourage cattle farmers to plan their lungworm prevention strategy now, especially where there is previous history of the disease on farm.

“Vaccination of calves over two months-old requires two doses of the lungworm vaccine four weeks apart with a second dose at least two weeks before turnout, so time is of the essence.”

The principle aim of parasite control at lambing is to minimise pasture contamination with eggs passed from adult parasites.

The likelihood of lambs and ewes becomming infected when grazing can be determined by the previous use of pastures.

Maximising the use of 'safe grazing' at turnout will help avoid the risk of nematodirosis, and parasitic gastroenteritis in lambs later in the season.