Diseases threaten dairy industry
THEY’RE battling with deregulation and major supermarket chains over prices and now dairy farmers should be worried about the threat of four emerging cattle diseases that could threaten the industry.
Dr Rob Bonanno, who will talk at the Australian Veterinary Association’s conference in Adelaide this week, said the diseases need to be monitored closely.
“These four new diseases are a fatal cattle liver disease thought to be caused by an annual grass and a plant fungus, lameness caused by hairy heel warts, Haemorrhagic Bowel Syndrome and the growing issue of zinc toxicity,” Dr Bonanno said.
“Many of these new cattle diseases have become increasingly common due to the extremely wet weather conditions we have been having in recent months.
"A trend towards larger herd sizes is also correlated with many emerging diseases of importance.”
According to AVA and Dr Bonanno, the cause of Acute Bovine Liver Disease, which has been recorded in Western Australia, South Australia, Tasmania and Victoria, is not clear but it is associated with warm humid conditions and the presence of an annual grass called Rough Dog’s Tail which has a specific fungal growth. Symptoms of ABLD can include sudden death, severe milk drop, acute abdominal pain and sensitivity to sunlight with marked photosensitisation (sunburn).
“(Hairy heel warts) disease has become one of the leading causes of lameness in confinement dairy herds in North America and Europe, and is being diagnosed increasingly in Australia, especially on farms that have adopted intensive systems of production,” Dr Bonanno said.
The disease is caused by exposure of the feet to a slurry of manure resulting from poor drainage or poor hygiene protocols, damage to the feet caused by rough flooring or poor pathways wear damage due to sand or poor tracks, and maceration of the skin due to wet muddy conditions.
Haemorrhagic Bowel Syndrome is being reported with increasing frequency in lactating dairy cattle in recent years. This sometimes presents as a cause of sudden death, but also sudden milk drop, abdominal pain, and loss of appetite.
The exact cause of HBS is not known, however risk factors may include rumen and post rumen acidosis, fungal infections such as aspergillus, or clostridial bacterial infections.
Although zinc toxicity is rarely seen in Australia, it can be a symptom of use of excessive supplementation in the diet to prevent Facial Eczema or zinc sulphate contamination of feed.