Selective Breeding: The Belgian Blue Cattle

Abstract
When comparing a Siberian husky to a Rottweiler there is a vast number of differences in their appearances; ears, color of coat and tails just to name a few. However, these dogs originate from the same species, but through artificial selection have become very different. Canines are one of the most common species that has been genetically altered to achieve a desirable appearance more pleasing to humans. Artificial selection is the process of selective breeding of closely related species (plant or animal) to achieve a more desirable trait in their offspring. Many different species have been altered through selective breeding. Selective breeding is a very common practice in the livestock breeding and has impacted the livestock industry
Cattle breeders begin to breed select breeds of cattle that appeared larger together in hopes of producing offspring with a larger quantity of meat. The selective breeding began with the Durham Shorthorns and Friesian cattle. (Lee, 2004) The result of the selective breeding produced 3 different strands of cattle breeds the Belgian Blue, Piedmontes and Parthenias. These breeds of cattle all have one similarity, that has proved to be very valuable, the inactive Myostatin protein. Due to the inactive Myostatin protein these cattle produce roughly 20 % more meat than other cattle. The Belgian Blue cattle are a common breed of cattle in the beef and livestock industry representing the double muscle trait caused by the inactive Myostatin protein.

Myostatin
In 1997 a research team from John Hopkins School of Medicine led by geneticists Dr. Se-Jin Lee and Alexandra McPherron released information from their research on how proteins regulate the growth of tissue in mice. Through their research the team unintentionally discovered the growth differentiation factor 8 (GDF-8) also known as Myostatin protein. With the discovery of the Myostatin protein the team decided to produce a mutant strain of mice that did not have
Cow breeders, who were under economic pressure from cheaper imports and high production costs, wanted to increase their yields and began to select for the double-muscling trait, which had been reported as early as 1807. Before long, nearly every beef cow in Belgium was a purebred double-muscled animal. (Dickman, 1997) Belgian Blue male cattle can weigh up to 1047lbs at one year old and up to 1709lbs at two years. The female Belgian can weight 816lbs at one year and 1102lbs at two years. In an extensive 3 year test, done by the USDA at the Meat Animal Research Center, Clay Center, Nebraska, the Belgian Blue crossbred cattle were tested with the industry standard Warner-Brazner shear test for tenderness. The Belgian Blue cattle had a lower shear value than the Hereford-Angus contemporary average, 12.8 versus 12.9, with comparable tenderness and flavor on the sensory panel. Belgian Blue cattle also exhibited less than half the fat cover, .21 inch cover versus .45 inch cover, a 53% reduction. Belgian Blue is on line for the new standards. The Belgian Blue also showed 16% less marbling and 14.2 more ribeye area than the average carcass. (Oklahoma State university,