Which cattle breed is famous for its extremely muscular body and Belgian origin?

The Belgian Blue is the cattle breed famous for its extremely muscular body and Belgian origin. Its striking appearance comes largely from a natural mutation affecting the myostatin gene, which regulates muscle growth.

This condition, called double muscling or muscular hypertrophy, produces unusually large muscle mass and a high proportion of lean meat. Belgian Blue cattle are usually blue-roan, white, or black-and-white, despite the breed name.

The breed developed in central and upper Belgium during the nineteenth and twentieth centuries from local cattle and selected British breeds. Its heavy musculature can make calving difficult, so breeders often use planned veterinary and reproductive management.