Belgian Blue - Breed Characteristics

Breed Characteristics

The Belgian Blue has a natural mutation in the myostatin gene which codes for the protein, myostatin ("myo" meaning muscle and "statin" meaning stop). Myostatin is a protein that acts to inhibit muscle development. This mutation also interferes with fat deposition, resulting in very lean meat. The truncated myostatin gene is unable to function in its normal capacity, resulting in accelerated lean muscle growth. Muscle growth is due primarily to physiological changes in the animal's muscle cells (fibers) from hypertrophy to a hyperplasia mode of growth. This particular type of growth is seen early in the fetus of a pregnant dam, which results in a calf that is born with two times the number of muscle fibers at birth than a calf with no myostatin gene mutation. In addition a new born double-muscled calf’s birth weight compared to a normal calf is significantly greater.

Belgian Blue cattle have improved feed conversion ratio (FCR) due to lower feed intake compared to weight gain. The ability for these animals to have improved FCR is due to an altered composition of body weight gain which includes increased protein and decreased fat deposition. Since the Belgian Blue’s bone structure is the same as a normal cow, however holding a greater amount of muscle, causes them to have a greater meat to bone ratio. These cattle have a muscle yield of about 20% more on average than cattle without the genetic myostatin mutation. Because of this breed’s increased muscle yield a diet containing higher protein is required to compensate for the altered mode of weight gain. During finishing this breed requires high-energy (concentrated) feeds, and will not yield the same results if put on a high-fiber diet.

The value of the double-muscling breed is due to their superior carcass characteristics. However with decreased fat content there is decreased marbling of meat, which means the meat tenderness is reduced. Conversely, the Belgian Blue's meat tenderness has been argued to be just as tender because there are a large number of smaller muscle fibers. The Belgian Blue's meat cuts also have a lower collagen content, which allows the protein quality to be improved due to a higher yield of amino acids.