Acute bovine liver disease (ABLD), previously known as phytotoxic hepatitis, is a disease of beef and dairy cattle. Tasmanian livestock owners and veterinarians are being asked to be on the lookout for symptoms of ABLD in their herds, following a recent episode that is highly suspicious of ABLD on a property in northern Tasmania.
The signs of ABLD are variable. Affected cattle may be distressed, agitated, seek shade and develop sunburn on the muzzle and areas of pale skin, such as white faces, white patches, udder and vulva. Other signs may include fever, a drop in milk production and depression. Other species such as sheep and horses are not affected.
An annual grass known as rough dog's tail (Cynosurus echinatus) is often associated with cases of ABLD, however it is unknown whether the plant is directly involved or whether it is merely an 'indicator' of some other factor.
Because many cases of ABLD are associated with warm, moist weather in autumn or spring, a fungal toxin associated with rough dog's tail has been suggested as being a possible cause. To date a fungus species, Pyrenophora (previously known as Dreschlera), has been identified as a candidate however this is yet to be confirmed. There is no current evidence that the plant itself is toxic. State departments of agriculture and primary industry are currently studying cases in an attempt to identify the cause(s).
There is no known cure for the condition. Although recovery is normally prolonged, early intervention by a veterinarian may assist with recovery by the use of medications such as anti-inflammatories, anti-histamines and zinc.
Paddocks may remain 'toxic' for variable lengths of time (hours to months) following an ABLD event. It is unknown whether 'toxic' paddocks will be 'toxic' in future years.
Management options include:
- eating out the paddock with sheep to reduce the amount of dry standing material,
- cultivation of high risk paddocks,
- avoiding grazing cattle on paddocks with an abundance of dry material which have been spelled for extended periods of time, and
- trying cattle again but with only a few animals at first to test for 'toxicity'.
Cattle should be frequently observed if grazed on 'at-risk' paddocks during 'danger' periods, particularly during autumn and spring. Cattle should be moved off the paddock immediately if any unusual signs are observed.
If you suspect a case of ABLD, contact your veterinary practitioner promptly.