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Beyond the Bale : September 2019
DAGS. DON’T GET CAUGHT UP S**T CREEK 54 ON FARM In southern Australia, managing sheep to prevent scouring and dag formation is vital to sheep health and well-being, including decreasing their susceptibility to breech strike. It will also save you from an unpleasant task of crutching and its associated labour costs, devalued wool and treatment costs. AWI recently completed a review of the causes, diagnosis, management and treatment of scouring in sheep. The review was conducted by Dr Joan Lloyd, Dr Caroline Jacobson, Dr John Larsen and Dr Brown Besier. From the review, a manual for advisors about dealing with dag and a related fact sheet for woolgrowers have been produced. The review team said there are many and varied causes of scouring and dags in sheep. “High worm burdens are the main cause of scouring and dags in Australian sheep, but are not the only cause,” Dr Lloyd said. The formation of dags is related to the While there are many causes of scouring and dags in Australian sheep, high worm burdens are the main reason. Spring is when there are the most infective worm larvae on the pasture, so now is the ideal time to review your management of dags, which you can do with the help of two new publications from AWI. consistency of faeces, with softer faeces sticking to the wool leading to accumulation of dags. Sheep that are scouring can rapidly form dags, and once dags start forming, more faeces stick to existing dag and the problem gets worse. Dr Larsen said the direct financial costs (see Table 1 opposite) of dags accrues from the need for crutching and the loss of value for the wool, along with treatment costs, and importantly, an increased susceptibility to breech strike . There may also be additional costs at slaughter. DIAGNOSING THE CAUSE “Diagnosing the cause of scouring in a mob of sheep need not be a daunting prospect,” Dr Besier said. “In most cases, taking a systematic approach, working through the potential causes and considering appropriate risk factors – such as age of the sheep and proportion of the mob affected; region, type of pasture and rainfall; and the time of year – will elucidate the most likely cause. “In many cases, the cause of scouring will be relatively simple and directly related to a break-down in on-farm worm control programs leading to excessively high burdens of intestinal parasites.” As such, the best approach to dealing with dags begins with considering the history of the flock and a faecal worm egg count. Results showing high counts (typically >500 eggs per gram) indicate that intestinal worms are the likely cause of scouring. In such cases, drenching with appropriate treatments can be expected to rectify the problem. However, the researchers warn that the link between scouring and worm burdens is complex, and that there are other causes of scouring and dags. “Even on farms with good worm control programs, scouring and dag can be observed in up to 70% sheep, depending upon the area, seasonal conditions and availability of pasture,” Dr Larsen said. “In south-eastern Australia, Crutching costs, reduced fleece value and treatment costs associated with dags impact farm profitability. Preventing scouring and dag formation is also vital to sheep health and well-being, including decreasing their susceptibility to breech strike. PHOTO: John Larsen
In the Shops - September 2019