Old McDonald Wouldn’t Recognize This Cow. It’s Been Bred To Be A “Super Cow”

Question

Meet the Belgian Blue, the cattle version of Arnold Schwarzenegger! Contrary to what you may think, these bovine bodybuilders aren’t the result of intensive steroid use. Similarly, to the featherless chicken, this man-made monstrosity is a prime example of the genetic power that selective breeding holds.

History & Origins

As suggested by its name, the breed originates from central and upper Belgium. Its history tracks back in the nineteenth century, from crossing local breeds with a Shorthorn breed from the U.K. Possibly, the Charolais cattle (a heavy breed from France) was cross-bred as well.

The modern version of the breed was developed in the 1950's by Professor Hanset, who worked at an artificial insemination center in Liege province. The gene mutation responsible for the breed’s heavily muscled stature (more on this later) was maintained through line-breeding, to the point where the condition became a fixed property of the Belgian Blue breed.

The breed was introduced in the United States in 1978, by Nick Tutt, a farmer from central Canada who immigrated to west Texas and exhibited the Belgian Blue to the local universities and breeders.

Why is the Belgian Blue so Muscular?

The Belgian Blue's sculpted, heavily muscled, bodybuilder-like appearance is known as "double-muscling." The condition is heritable and results from an increased number of muscle fibers (hyperplasia) rather than the normal enlargement of individual muscle cells (hypertrophy).

The increased muscle tissue is due to a natural mutation in a gene which is involved in muscular hypertoryphy. This gene is responsible for the expression of a protein called myostatin ("myo" meaning muscle and "statin" meaning stop). You probably guessed it right, myostatin inhibits muscle growth. Essentially, the breed produces less myostatin and thus produces more muscle tissue than the average cattle. Furthermore, the same mutation apparently interferes with fat deposition, resulting in very lean meat.

Physical Characteristics

The Belgian Blue is a large sized cattle breed, with rounded outline and prominent muscles on the shoulders, back, loin and rump. The back is straight, rump is sloping, tail set is prominent and the skin is fine. The legs are thin but strong. Individuals vary in color, which may be while, blue roan or sometimes even black.

Meat Quality and Nutritional Value

Several studies have shown that the meat and milk produced by Belgian blues can be consumed with no risk by humans.

In an extensive 3 year examination, done by the USDA at the Meat Animal Research Center, Clay Center, Nebraska, it was observed that Belgian blue meat contains less fat and more protein.

Constructed Response Question
The Belgian Blue is a special breed of cow which has a special double-muscled body. Because of this trait, Belgian Blue cows have reduced fat meat. Using information from the passage and your understanding of science, explain how scientists have used selective breeding to create the Belgian Blue Cow

Answer 1

Selective breeding is a process where humans choose certain traits that they want to see in an organism and intentionally breed individuals with those traits together in order to pass them on to future generations. In the case of the Belgian Blue cow, scientists have used selective breeding to create this double-muscled trait.

The gene mutation responsible for the heavily muscled stature of the Belgian Blue is maintained through line-breeding, where individuals who already possess the desired trait are bred together to increase the likelihood of passing on that trait to offspring. By selecting for individuals with the gene mutation that leads to increased muscle mass and less fat deposition, scientists have been able to create a breed of cow that is known for its lean meat and muscular build.

Through this process of selective breeding over generations, the Belgian Blue has become a "super cow" with unique physical characteristics that are not found in other cattle breeds. This demonstrates the power of genetic manipulation through selective breeding in creating desired traits in organisms for human benefit.