WASHINGTON -- A government official said the second confirmed case of mad cow disease in the United States was a cow from Texas killed last November.

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The officials didn't want to be identified because the Agriculture Department plans an announcement later.

The case was announced Friday, after tests were conducted in a laboratory in England to confirm it.

The infected cow was said to be traced to a rendering plant for animals unfit for human consumption. The cow -- a "downer" that could not walk -- was more than 8 years old when it arrived at the plant. The officials said that could mean the animal might have contracted the disease through animal feed that included cow parts.

The United States banned using cattle parts in such feed in 1997 following an outbreak of mad cow disease in Britain. Eating the brain and other nervous tissue of an animal with the brain-wasting ailment is the only confirmed way the disease is transmitted.

The first case of mad cow disease in the United States was confirmed in 2003 and involved a dairy cow imported from Canada. Mad cow disease has killed about 150 people worldwide, mostly in Britain.

Meanwhile, the chairman of the House Agriculture Committee said a livestock tracking system is needed "as soon as possible."

But Virginia Rep. Bob Goodlatte said he believes the beef industry can implement a tracking system faster than the government.

A lobbyist for the National Cattlemen's Beef Association said the group is creating its own identification system to track the country's 96 million cattle.

The goal is to start testing that plan in October 2005 and have it fully in place by October 2006. The government's goal is to make a system mandatory by January 2009.