Question
Old McDonald Wouldn’t Recognize This Cow. It’s Been Bred To Be A “Super Cow”
Old McDonald Wouldn’t Recognize This Cow. It’s Been Bred To Be A “Super Cow”
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.
Answers
GPT-4o mini
Selective breeding is a powerful tool that scientists and breeders have utilized to enhance specific traits in animals, and the creation of the Belgian Blue cow demonstrates this process effectively. The Belgian Blue’s unique double-muscling trait is primarily due to a genetic mutation that reduces the production of a protein called myostatin. Myostatin normally inhibits muscle growth, so by producing less of it, these cows are able to have more muscle fibers and thus a heavily muscled appearance.
The history of the Belgian Blue begins in the nineteenth century in Belgium, where local breeds were crossed with Shorthorn cattle from the UK, and possibly Charolais cattle from France. This initial crossing introduced variability that breeders capitalized on. In the 1950s, Professor Hanset focused on a specific trait: the double-muscling caused by the gene mutation affecting myostatin. Through a process known as line breeding—selectively mating individuals that exhibit desirable traits—he was able to maintain and establish this mutation within the population, solidifying the physical characteristics associated with the breed.
Additionally, the gene responsible for this condition was effectively isolated through generations of selective breeding, ensuring that more cattle expressed the double-muscling trait. This resulted in an increased quantity of muscle fibers compared to normal cattle, which leads to leaner meat with reduced fat content—a notable advantage from both a meat quality and health perspective.
In summary, scientists used selective breeding by identifying and perpetuating the desired genetic mutation associated with myostatin levels, allowing for the development of a breed that not only has a unique muscular appearance but also provides nutritional benefits through its lean meat. The Belgian Blue cow is a clear representation of how selective breeding can shape animal physiology for specific outcomes.
The history of the Belgian Blue begins in the nineteenth century in Belgium, where local breeds were crossed with Shorthorn cattle from the UK, and possibly Charolais cattle from France. This initial crossing introduced variability that breeders capitalized on. In the 1950s, Professor Hanset focused on a specific trait: the double-muscling caused by the gene mutation affecting myostatin. Through a process known as line breeding—selectively mating individuals that exhibit desirable traits—he was able to maintain and establish this mutation within the population, solidifying the physical characteristics associated with the breed.
Additionally, the gene responsible for this condition was effectively isolated through generations of selective breeding, ensuring that more cattle expressed the double-muscling trait. This resulted in an increased quantity of muscle fibers compared to normal cattle, which leads to leaner meat with reduced fat content—a notable advantage from both a meat quality and health perspective.
In summary, scientists used selective breeding by identifying and perpetuating the desired genetic mutation associated with myostatin levels, allowing for the development of a breed that not only has a unique muscular appearance but also provides nutritional benefits through its lean meat. The Belgian Blue cow is a clear representation of how selective breeding can shape animal physiology for specific outcomes.