Staff from Agriculture Victoria worked with local private vets and farmers near Mirboo to assess cattle losses and determined that theileriosis was the most likely cause.
Also known as bovine anaemia, the disease is caused by the Theileria orientalis group of parasites.
It strikes when ticks carrying the parasite feed on cattle.
Once in the bloodstream, the parasites can cause damage to red blood cells, potentially making the animal anaemic.
Signs of the disease are those associated with anaemia and include lethargy, lack of appetite, cattle lagging the mob when being moved and gasping for breath if running.
The gums of anaemic cattle will be pale or yellow.
Agriculture Victoria Senior Veterinary Officer south-east Dr Dianne Phillips said Agriculture Victoria is keen to provide advice to farmers to help with issues associated with theileriosis, even though there is no vaccine for the disease.
"From time to time, we do see cattle losses from theileriosis, which is spread by bush ticks," Dr Phillips said.
"As the weather warms up moving into spring, local tick populations may become more active, resulting in exposure of animals to this disease.
"Unfortunately, treatment options for theileriosis are limited to supportive care and treatment of symptoms.
"Pregnant cattle are particularly at risk and the introduction of these into theileria-prevalent areas should be avoided."
Dr Phillips said animals which were in good health with appropriate vaccinations, nutritional intake and vitamin and mineral status have a better chance of surviving infections.
Cattle which are clinically affected should not be moved and ideally not handled, allowing them to quietly recover in a paddock with good feed, water and shelter.
If animals must be moved, it is necessary to move them slowly to avoid problems.
Dr Phillips said producers should speak to their veterinarian or Agriculture Victoria staff if they have any concerns about the health of their livestock.