http://www.digitaljournal.com/tech-and-science/science/one-bull-gave-rise-to-2-million-great-grandaughters/article/478897

One bull gave rise to two million great-grandaughters

Posted Nov 5, 2016 by Tim Sandle
One bull, called Pawnee Farm Arlinda Chief, had more than two million great-granddaughters, making him the most successful bovine in history. However, it also appears he had a genetic defect and this has spread through Holstein populations.
Holstein-Friesian milk cow
Holstein-Friesian milk cow
Keith Weller / USDA
A bull called Pawnee Farm Arlinda Chief (often abbreviated to just 'Chief') was probably the most successful bull of all time. The bull, through regular mating exploits, gave rise to 16,000 daughters. After this came 500,000 granddaughters, and then a mind-boggling two million great-granddaughters. According to The Atlantic, the bull's genes account for 14 percent of all DNA in Holstein cows. The bull was born in 1962, a time that coincided with advances in artificial insemination (which accounts for the widespread use of the bull's semen).
Holstein cows are the most popular breed in the U.S. dairy industry. Holstein Friesians (most commonly called Friesians in Europe, and Holsteins in North America) originated from the Netherlands. Holsteins have distinctive markings, usually black and white or red and white in color. The cows are renowned for their milking qualities.
Despite Chief's success in breeding, geneticists later identified that the bull carried a single copy of a serious mutation, and this mutation spread through the Holstein cow population. The mutation has caused several unborn calves to die in the womb, up to 500,000 spontaneous abortions and this has cost the U.S. dairy industry $420 million in losses.
On the other hand, the Chief's breeding is estimated to have added $30 billion dollars in increased milk production over the past 35 years to the U.S. dairy industry. In this sense, the increased milk production, and the value of a prized bull, outweighs the loss of cows. On the other hand, as genetics advances, the risks of over-reliance upon one prized male are manifest in the loss of calves.