US and Japanese researchers may have developed an breed of genetically-engineered cows that can resist Mad Cow Disease (also known as bovine spongiform encephalopathy or BSE). They used a method known as gene targeting to get rid of the prion-protein gene, which is known to be a causing factor in Mad Cow Disease and also various brain diseases in humans. The cows in this experiment are now 2 years old and completely healthy but it is not yet known if they can breed normally yet. These cows will be used to study prion-protein processes, which may one day be useful in brain disease research in humans as well.
Source: Environmental News Network, Gene-Engineered Cows Resist Mad Cow Disease, by Reuters, January 2