LUBBOCK, Texas -- Nearly all cows in the US herd were born after federal feed bans were enacted in 1997 to protect against mad cow disease, according to estimates from industry groups.
The National Cattlemen's Beef Association estimated 97 percent of the 96 million head of cattle in the country have never eaten food tainted with animal parts.
Industry officials said the estimate -- coupled with the fact that only older cows typically get infected -- show that the 12-year-old Texas cow found to have mad cow this week was an anomaly and the risk of the disease is on the decline.
Eating brain and other nervous system tissue of an animal with mad cow is the only way the disease is known to spread.
While the few animals that were born before the ban and are still alive may have eaten tainted food, industry officials said their age alone is an added safeguard for the food supply.