Michael McGowan is Professor of Livestock Medicine and Head of the Veterinary Population Health and Production section in the School of Veterinary Science at the University of Queensland.

Mr McGowan informed the group that after foot and mouth, BVDV was the next most important viral infection and was found in cattle throughout the world.

He said that to date, the infection had been slipping under the radar, but with modern farming techniques it had become easier to detect, but also easier for transmission of the virus.

The virus is in all body fluids of infected animals and simple nose touching can cause the virus to be transmitted from animal to animal.

In 1967 it was discovered that 90 percent of cattle tested in one herd had been infected, and it can now be found in all major beef-breeding areas in Australia, the US and the UK.

There are two known types of the virus, type-1 and type-2, with type-2 being the most virulent, with an outbreak in the north of the US and Canada re-sulting in a 40pc mortality rate.

Type-2 has not been detected in Australia and the Australian Quarantine and Inspection Service has been put on notice to test all incoming live cattle.

Many cattle become infected in the womb.

Most of these are aborted or die early, but those that survive to adulthood are known as permanently infected animals (PIs) and these cattle are the major source of infection for other cattle.

Cattle can be tested for antibodies to BVDV by an ear knot test and a vaccine, Pestiguard, is available for BVDV, but to vaccinate big herds would be extremely expensive.

Prof McGowan suggested that seedstock producers should be conducting their own bio-security by testing all animals they purchase, as semen from infected sires will transmit the virus every time it is used.

Symptoms of BVDV include ulcers in the throat and bowel, but there is no public health risk in consuming BVDV animals.

Recent tests done on a property in the Mount Surprise area that had experienced a 50pc drop in calving rate revealed the herd had become seriously infected by PI cattle brought on to the property last year.