Skip Navigation

Mad Cow Disease

Author(s): Sonia Rahmati Clayton, PhD, James Denk, MA, and Nancy Moreno, PhD

Mad Cow Disease: An Introduction

Mad cow disease (known scientifically as Bovine Spongiform Encephalopathy, or BSE) is a disease that attacks the nervous system of adult cattle. The name "mad cow" comes from the strange behavior and symptoms seen in cattle that have the disease. These behaviors and symptoms include: aggression, lack of coordination with inability to stand or walk, and abnormal posture. BSE was first identified by a veterinarian in England in 1986. BSE is a fatal disease that progresses very slowly.

The name, Bovine Spongiform Encephalopathy, describes characteristics of the disease in scientific language. "Bovine" indicates that it is a disease of cattle. "Spongiform" refers to the spongy appearance of the brains of infected cattle. "Encephalopathy" is a term that refers to a disease of the brain, especially one involving alterations of brain structure.

Scientists believe the disease may have passed to cattle through feeds containing animal proteins from sheep with a similar disease, known as scrapie. The disease may spread to other cattle through feeds containing meat and bone meal from infected cows. In the United States, it has been illegal to feed most animal proteins to cattle since 1997.