In the late 18th century, shorthorn cattle were specifically bred for their beef qualities. Later, some shorthorns were developed for optimal milk production, and shorthorn types were divided; today there are milking shorthorns and beef shorthorns. Both kinds are known for their mild temperaments and their ability to crossbreed favorably with just about any other type of cattle.
Genetic Defect - Tibial Hemimelia
Two serious genetic defects exist in a popular bloodline of shorthorn cattle. One is tibial hemimelia. As the shorthorn is often bred with other cattle types, the disorder has spread to other breeds and is not exclusive to the shorthorn. The lethal genetic defect results in calves born with deformed legs, abdominal hernias, skull deformity and fused joints. Deformed calves are unable to nurse and often don't survive long after birth. Those who do survive are put down in order to stop the spreading of the genetic mutation.
Pulmonary Hypoplasia With Anasarca
In 2005, Dr. Chuck Hannon discovered pulmonary hypoplasia with anascara in the shorthorn breed while he was investigating tibial hemimelia. It is traced to the Maine-Anjou breed and is thought to have originated from a bull born in 1970. PHA is a lethal malady that results in fluid buildup in the skin and body cavities of calves. This results in heavier and larger fetuses. Dead calves with PHA are also found with underdeveloped lungs.
Out-Competed for Milk Production
While milking shorthorns were bred to develop their milk-producing abilities, they originated from the same shorthorns, which were developed for optimal beef quality in the late 18th century. Thus, milking shorthorns cannot compete with other breeds like the Holstein when it comes to milk production quantity.
Diluted Bloodline
Milking shorthorn cattle have been crossed with outside breeds in an effort to increase their milk production, resulting in a decline of the pure bloodline. Many shorthorns that are registered now are actually half Holstein or more. The milk production increased, but the genetic uniqueness of the breed declined -- certain traits shorthorns were known for have lost consistency, such as the ability to produce on grass. In the United States, conservation of purebred shorthorns is a priority because of the decline in their pure bloodline.