Most U.S. Dairy Cows Are Descended From Just 2 Bulls. That's Not Good.

Merin Porter
Merin Porter Posts: 1,026 admin
edited October 2020 in Other News

"....A few years ago, Dechow and some of his colleagues at Penn State made a discovery that shocked a lot of people. All the Holstein bulls that farmers were using could trace their lineage back to one of just two male ancestors. "Everything goes back to two bulls born in the 1950s and 1960s," he says. "Their names were Round Oak Rag Apple Elevation and Pawnee Farm Arlinda Chief."

This doesn't mean that the bulls in the catalog are genetically identical. They still had lots of different mothers, as well as grandmothers. But it does show that this system of large-scale artificial insemination, with farmers repeatedly picking top-rated bulls, has made cows more genetically similar. Meanwhile, genetic traits that existed in Holstein cows a generation ago have disappeared.

"We've lost genetic variation," Dechow says. "Now, some of that variation was garbage that we didn't want to begin with. But some of it was valuable stuff."

To see what might have been lost, Dechow decided to do an experiment. He located some old semen from other bulls that were alive decades ago, with names like University of Minnesota Cuthbert and Zimmerman All-Star Pilot. You might call them heirloom bulls. The U.S. Agriculture Department keeps samples of their semen in deep-freeze storage in Fort Collins, Colo.

Dechow used that semen to impregnate some modern cows. They gave birth, and now it's possible to see some lost pieces of the Holstein family tree come to life in a barn at Penn State — in the form of three cows...."


  • Obiora E
    Obiora E Posts: 517 ✭✭✭✭

    Thank you for sharing. I heard a portion of the story on NPR last week. And in some ways, this may help to explain the reason that lactose-intolerance and other issues tied to cow's milk has increased since the 1990s in the United States.

  • LaurieLovesLearning
    LaurieLovesLearning Posts: 7,375 admin

    @Obiora E I think that issue has more to do with feeding/supplement choices through processing.

    We know a good Mennonite small dairy farmer (30 cows) here in Canada who selects for stockier stock. They look more like the traditional Friesan seen in Europe than what is normally seen in North America. They actually look more plump & shorter than the usual. He says that they are healthier. They still have large udders and give plenty of milk. He is happy with them.

    I prefer their looks way over the ultrabony Holstein. Unfortunately, our last Milking Shorthorn, as most Guernseys are today, do have Holstein blood due to what was considered "superior" bloodlines to create more milk with way less cream. It was not stated by the dairy guy (but it was obvious through certain traits). It is a sad state of affairs (in my opinion) as it affects many of their traits negatively, not staying true to breed.

  • Obiora E
    Obiora E Posts: 517 ✭✭✭✭

    You could be right, or we both could be right?! I have no idea but I guess one day we will know.

  • Obiora E
    Obiora E Posts: 517 ✭✭✭✭