The Belgian Blue is a breed of beef cattle from Belgium. It may also be known as the Race de la Moyenne et Haute Belgique, or dikbil. Alternative names for this breed include Belgian Blue-White; Belgian White and Blue Pied; Belgian White Blue; Blue; and Blue Belgian. The Belgian Blue's extremely lean, hyper-sculpted, ultra-muscular physique is termed "double-muscling". The double-muscling phenotype is a heritable condition caused by a deletion in the myostatin gene, resulting in an increased number of muscle fibres (hyperplasia), instead of the (normal) enlargement of individual muscle fibres (hypertrophy).