Mad cow disease is one of a family of illnesses known to infect animals such as cattle, sheep, elk and deer. Federal regulators and experts say there's no reason to worry about pets getting sick from pet food and no evidence to suggest any tainted meat has made its way into the pet food supply. Experts say the chances of cats in the United States contracting the disease are slim, though not impossible. Mad cow has been found in a small number of cats - about 100 - in the United Kingdom, as well as a handful in other European countries. There's never been a reported case of a dog getting it. The Food and Drug Administration sought comment last year as it considered a ban on using cattle brain and spinal tissue in food for dogs, cats, pigs and poultry. An FDA spokeswoman said no final decision has been made.