The Department of Primary Industries is advising dairy farmers to be on the look-out for mycoplasma mastitis.

 DPIPWE Veterinary Officer Dr Debbie Grull said that while mastitis caused by mycoplasma bacteria was relatively rare there had been a number of cases reported recently.

"The key problem with this disease is that carriers can be hard to identify because mycoplasma mastitis does not always show up in milk tests," Dr Grull said.

"Cattle with mycoplasma mastitis generally do not respond well to treatment.

If you have an increase in clinical cases of mastitis that are resistant to usual treatment practices, including dry cow therapy, the cause may be mycoplasma mastitis.

"This disease is highly contagious and can cause significant production losses.

"Regular herd testing is the best way to monitor whether there are subclinical cases of mastitis in the herd.

"As a matter of normal practice, all subclinical and clinical cases of mastitis should be cultured to determine the cause.

"So it is important to consult your veterinarian about mastitis issues in your dairy.

"There are no known effective treatments for mycoplasma mastitis.

"Therapy is often not an economical strategy to control the disease and only prolongs the time before the infected cow will be culled - and that cow can infect others in the meantime," Dr Debbie Grull said.