DALLAS -- State researchers tracking the herd associated with the nation's first domestic case of mad cow disease found that most of the cattle were slaughtered before federal officials started their inquiry and that incomplete records hampered the investigation.
One offspring of the infected cow could not be located and might have entered the food supply, the researchers said. However, transmission of the disease to a cow's offspring or to people is unlikely, a US Department of Agriculture official said yesterday.
The federal government closed its investigation in August, saying it could not pin down how the cow became infected with the brain-wasting ailment. The Agriculture Department and the Food and Drug Administration traced 413 animals and reported that 147 herd-mates and offspring of the infected cow were presumed to have been slaughtered for food, livestock feed, or other use, and that 21 could not be traced. The USDA killed and tested 67 animals, all of which tested negative for mad cow disease.
However, reports compiled for the Texas Animal Health Commission and obtained by the Dallas Morning News show that about 350, or 85 percent, of the 413 cows were sent for slaughter.
The state investigators found that many records were no longer available and they ended up using the state's own cattle health records from the county where the herd was located to get a picture of the herd's animals, the Morning News said.
The ranch where the infected cow was raised has not been publicly identified.
''If it were not for our brucellosis information and database, we would have had extraordinary difficulty in conducting this investigation," said Dr. Max Coats, deputy director for animal health programs at the Texas Animal Health Commission.
Brucellosis is a bacterial disease in cattle and other animals that can be passed to humans.
Researchers tracked 213 calves to find two that had recently been born to the diseased cow.
They were unable to specifically identify the two calves, but found that 208 went into feed and slaughter channels, entering the food supply, the newspaper reported. Four more probably did. One calf was untraceable.