Intensified farming practices to meet the growing demand for milk are pushing dairy cows to "exhaustion" and exacerbating welfare problems such as mastitis and lameness, animal activists claim.
Animal welfare group Voiceless will release a report this week into the dairy industry showing Australian farms are producing more milk using fewer cows in less space than ever before.
Australia's dairy cow population of about 1.8 million has remained stable for the past 30 years, but annual milk production has doubled to 9.3 billion litres in that time, figures from the Department of Agriculture show.
In Victoria, which produces two-thirds of total milk production, the cows' grazing area has shrunk by 35 per cent.
 
"The modern dairy cow commonly suffers from mastitis, lameness, metabolic disorders, mutilation procedures and the inevitability of repeatedly losing her calf," the report reads.
It goes on to say the cows' "pain and suffering" will worsen as farmers strive to balance local consumer expectations for cheaper milk and growing demand from overseas.
In November, the Abbott government signed a free-trade deal with China guaranteeing better access for the dairy industry.
"Reform is needed to address this situation, particularly if the current growth in milk output and the pressures toward intensification of dairying continue," the report says.
But Noel Campbell, president of peak body Australian Dairy Farmers, disputed the authors' conclusions, saying if greater demand pushed production goals to 12 billion litres a year, farmers would increase their herds by 25 per cent.
"My expectation is more land that is currently used for beef land and more land that is currently under-utilised by existing dairy farmers will mean they will milk more cows. They wouldn't be pushing the current cows harder."
Terry Toohey, a fourth-generation farmer on the NSW north coast, said his "healthy" cows were not overworked.
He said he could produce double the milk their predecessors did 30 years ago because of more nutritious feed, advanced technology and better milking practices.
"Also a hundred years ago farmers cleared a lot of the land and removed trees. A lot of farmers in the past 20 years have gone back and planted a lot of trees so they have wind-breakers and shady areas, and more watering points around the farm," he said. "All those add up to a considerable increase in production."
Mr Toohey is aware of some cows that can lactate 60 litres of milk a day. The industry standard is 30 to 50 litres.
Organic milk producer Ulli Spranz, owner of B.-d. Farm Paris Creek in South Australia, said a rate of 60 litres a day was "over the top" and could compromise the quality of the milk.
"You cannot have the same quality milk from those high-producing cows. The calcium content is much less," she said.
Ms Spranz does not let her cows produce more than 20 litres a day.
"Even from a financial point we can see that the cows are healthier, produce better milk, need less veterinary attention, have stronger bones, and live longer, if we keep it at 16 to 20 litres a day," she said.
Voiceless hopes its report will help shape the new cattle welfare code, which is in the final stages of review.
On top of the issue of overworked cows, it raises welfare concerns such as tail docking, dehorning, and disbudding, as well as the treatment of bobby calves.
It recommends developing a national licensing scheme to promote best practice, and an independent assurance scheme to encourage an ethical consumer base.
Voiceless will launch the full report on January 28 and send a digital copy to MPs.
