Theme 10: Animal Comfort

Description

Dags are the accumulation of faeces on wool in the perianal (breech) region of sheep and are a common problem in sheep fed good quality ryegrass based pastures in New Zealand. Their removal, or prevention, is costly but the consequences of doing nothing are severe. There is a high correlation between dags and flystrike (development of maggots) on sheep with dags, and dags reduce fleece value, live-weight gain and reproductive performance. Information summarised here suggests a range of factors contribute to the incidence of dags: lush (high quality) feeds, high voluntary feed intakes, presence of parasites in the gastro-intestinal tract, ingestion of parasite larvae, ingestion of fungal endophyte and a genetic predisposition to loose faeces. Faecal co elements, dry ground roughage, gums, detergent, serum, lanolin and water and measuring effects on adhesion. Other tests included measurement of faecal form, wool type and diet. Pelleted faeces did not adhere to wool, but interference with faecal form (e.g. mixing faeces) appeared to increase adhesion. It was concluded that faecal form was the most important factor affecting the incidence of dags and although conditions resulting in soft gooey faeces would facilitate their development, the chemical composition of faeces and of pasture were not the principal causes of dag formation. Factors associated with a high incidence of dags may increase the rate of digesta passage through the large intestine and/or alter intestinal function to affect faecal form and the adhesion of faeces to wool.

Share

COinS
 

Dags in Sheep Grazing Temperate Pastures: Causes and Consequences of Faecal Adhesion to Wool

Dags are the accumulation of faeces on wool in the perianal (breech) region of sheep and are a common problem in sheep fed good quality ryegrass based pastures in New Zealand. Their removal, or prevention, is costly but the consequences of doing nothing are severe. There is a high correlation between dags and flystrike (development of maggots) on sheep with dags, and dags reduce fleece value, live-weight gain and reproductive performance. Information summarised here suggests a range of factors contribute to the incidence of dags: lush (high quality) feeds, high voluntary feed intakes, presence of parasites in the gastro-intestinal tract, ingestion of parasite larvae, ingestion of fungal endophyte and a genetic predisposition to loose faeces. Faecal co elements, dry ground roughage, gums, detergent, serum, lanolin and water and measuring effects on adhesion. Other tests included measurement of faecal form, wool type and diet. Pelleted faeces did not adhere to wool, but interference with faecal form (e.g. mixing faeces) appeared to increase adhesion. It was concluded that faecal form was the most important factor affecting the incidence of dags and although conditions resulting in soft gooey faeces would facilitate their development, the chemical composition of faeces and of pasture were not the principal causes of dag formation. Factors associated with a high incidence of dags may increase the rate of digesta passage through the large intestine and/or alter intestinal function to affect faecal form and the adhesion of faeces to wool.