Double muscling
An inherited condition giving cattle greatly enlarged muscles, especially over the hindquarters.
Also: muscular hypertrophy, culard
Double-muscled cattle carry much more muscle than usual, with rounded, deeply grooved hindquarters, thin skin and little fat. The animals do not have extra muscles; their muscle fibres are more numerous. The Belgian Blue and the Piedmontese are the best known breeds with the trait, and it also occurs in some other European breeds; the French call such animals culard. It is caused by variants of the myostatin gene. Double-muscled cattle give a high share of lean meat, but cows of the most extreme lines more often need help calving, and many Belgian Blue calves are born by caesarean section. Breeders and welfare bodies continue to debate the balance.