Dags in sheep; a look at faeces and reasons for dag formation

Dags represent a major cost to sheep farmers, in both monetary terms and because of the stress associated with flystrike. Historically, the incidence of dags has been attributed in large part to worm burdens, but other causes may be more important, viz parasite larval challenge, fungal endophyte and selection of sheep for resistance to worms. These and other factors associated with the incidence of dags are summarised, together with variations in faecal types (physical and chemical composition) which affect their capacity for adhesion to wool. Much of these data emphasise the importance of differences or changes in intestinal function being responsible for the loose and gooey faeces which develop into dags. Flystrike is strongly correlated with dags, and this scenario cannot be tolerated in a country claiming to produce good, clean food.