Steak back on the menu after mad cow disease tests prove negative

Beef and steak lovers in the U.S. can relax and throw a few more steaks on the barbie, now that tests on over 60 cows culled from the same herd of an animal which was found to be infected with mad cow disease, have tested negative.

The U.S. Agriculture Department has confirmed that the testing, which was conducted by the National Veterinary Services Laboratory in Ames, Iowa, found the 67 cows removed from the herd on a ranch in Texas were negative for the disease.

Texas, which is the leading beef producing state in the nation has 13.8 million head of cattle.

According to the department the 12-year-old cow, which was the first infected animal, had spent its entire life at the ranch.

The animal was sold at a livestock market in November but was dead on arrival at a slaughterhouse a few days later.

It was then taken to a pet food plant in Waco, Texas, but apparently the animal was not used for food, and its brain tissue was removed for testing.

While one test indicated the presence of mad cow disease, results from a further test were negative.

Public concern was raised when months later, the department's inspector general ordered a third test, which showed the disease.

The presence of the disease was confirmed after a series of tests at a laboratory in Britain.

This is only the second case of mad cow disease to ever appear in the United States.