Belgian Blue cattle are also called "monster cows". They are a heavily-bred breed, producing incredible amounts of meat. The problem is that they are often unable to give birth without caesarean section.
Some countries (including Sweden) do not allow Belgian Blues.
This breed has a natural mutation of the gene that codes for myostatin, a protein that counteracts muscle growth. The truncated myostatin is unable to function in this capacity. This mutation also interferes with fat deposition, resulting in very lean meat.
Their sculpted, heavily muscled appearance is known as "doubled muscled", and is a trait shared by the Piedmontese breed.
- Discover magazine, January 2005, "Secret of Superboy's Strength Revealed"