Internal parasitic infection can pose major health problems in young livestock and this is particularly so in the context of lambs in organic production systems. In the context of sheep production on an organic farm the challenge to control parasite infection is especially difficult in situations where crop production is absent or a minor element of the whole farm system. Our investigations, to date at Athenry, have concerned an exploration of lamb production in an all-grass farming setting with particular attention being paid to the breeds employed and the seasonal patterns of gastrointestinal parasite challenge. This flock (about 110 ewes plus replacements) is wintered indoors and lambs in early March each year
