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2006 Parasitic Disease Forecast

Ms Mary Wallace TD, Minister of State at the Department of Agriculture and Food, today issued the following advice to farmers in regard to parasitic diseases.

Nematodirosis in lambs:

Nematodirosis is a severe disease of 6-12 week old lambs, which become infected through ingesting large numbers of infected larvae present on contaminated pasture. Infection is characterised by profuse diarrhoea and wasting and mortalities in untreated lambs can be high. Larvae invade the intestinal mucosa and death may occur before signs of diarrhoea induced by adult worms are observed.

This disease is best prevented by keeping the current year's lambs off pasture that was grazed by lambs last year.

Meteorological information and soil temperature data for March indicate that the greatest pasture contamination with infective larvae will occur during early to mid-April. Peak hatching of eggs will occur around the 10th April in counties Donegal, Sligo, Mayo, Galway, Clare, west Limerick, Kerry and west Cork i.e. areas west of a line from Malin Head to Mizen Head and also in south Wexford and east Waterford. In the south, midlands and north of the country Nematodirus eggs will hatch between the 12th and 14th of April. In the east hatching will occur on the 16th/17th April. However, in all these areas hatching in pastures on high ground will be delayed by about seven days.

As last month has been the coldest March for several years, lambs will be exposed to higher levels of Nematodirus challenge than in previous years. Therefore farmers should err on the side of caution, especially those with intensive sheep units, where safe pasture is not available and on farms where the nutritional status of the ewe is less than optimal. Lambs should be dosed with a suitable anthelmintic in late April or early May to decrease the likelihood of clinical problems later in the season and also to lower pasture contamination for the next year.

Coccidiosis in lambs:

As distinct from Nematodirosis, it is also important that farmers are aware that other parasites cause diarrhoea in young lambs, such as Coccidia, which require different control measures and medication. Rotation of pasture and frequent movement of feeding troughs and watering points help prevent coccidiosis in young lambs as localised poaching creates moist conditions suitable for the spread of this parasite.

It is advisable to consult a private veterinary practitioner for an accurate diagnosis and advice on appropriate medication if lambs with severe diarrhoea and straining are observed. Faecal samples can be submitted to the Central and Regional Veterinary Laboratories for testing. This service is available through veterinary practitioners and can be used to assess the level of parasite infection on farms and also to assist in the development of parasite control programmes.

11 April 2006


This press release is prepared in conjunction with the Nematodirus Advisory Group. This group comprises representatives from the Department of Agriculture and Food; Agri-Food and Biosciences Institute, Northern Ireland; Teagasc; Met Eireann; University College Dublin and the pharmaceutical industry.

Date Released: 11 April 2006