The way we breed cows is setting them up for extinction
There are more than 9 million dairy cows in the United States, and the vast majority of them are Holsteins, large bovines with distinctive black-and-white (sometimes red-and-white) markings. When researchers at the Pennsylvania State University looked closely at the male lines a few years ago, they discovered more than 99% of them can be traced back to one of two bulls, both born in the 1960s. “What we’ve done is really narrowed down the genetic pool,” says Chad Dechow, one of the researchers.