How to edit a cow? U scientist tinkers with livestock genetics

Dairy cows wait to be milked in West Bend, Wisconsin. (Darren Hauck/Getty Images)

You can edit text. You can edit video. But editing a cow?

There’s still a long way to go to the marketplace, but a University of Minnesota genomics scientist is hard at work to sell a new way to change the genetics of livestock. He’s even started a company, Recombinetics, based in St. Paul.

Scott Fahrenkrug calls his technique gene-editing. He says with it he can splice a desirable genetic change into an animal, without replacing an entire gene or genes. He published his research last week in the  ”Proceedings of the National Academy of Sciences.”

Fahrenkrug likes to use the literary world as a comparison for what he’s doing.

Consider a book containing three billion alphabetical letters. Now imagine changing just one of those letters, say from a “b” to a “t.”  He says that’s the scale of his gene-editing. He says a livestock’s genome contains about three billion ‘letters’ or bits of information. His technique can change one of those “letters” at a time.

“That gives us the ability to copy naturally occurring variations that are present in other breeds of livestock and bring them into the breed that we’re working with,” said Fahrenkrug.

He says he’s focusing on two areas right now. One is medical research. Fahrenkrug says using gene editing he’ll be able to create pigs with medical conditions similar to those humans suffer. It could be a certain type of heart disease for example. He believes medical researchers will be able to test new drugs on the pigs, and have a high degree of certainty that the drug will cause the same reaction in humans as found in the pigs.

The other area is livestock. He says he’s already produced a living cow that has 10 percent to 50 percent more muscle mass than its ancestors. He used a tropical breed of cattle known as the Nellore to achieve the results.

Another goal is to make a cow without horns. Fahrenkrug says that process is underway now, and that he should have a living, hornless animal in a year or so.

Texas A&M University livestock genetics professor Jim Womack says a hornless cow would be a big advancement for dairy and beef producers.  He says the current practice of removing a cows’ horns is dangerous for workers and painful to the animal.

“A genetic solution to dehorning is an absolutely wonderful idea and a great accomplishment,”  said Womack.

All of this must meet government regulatory approval before it reaches the market place, a process Fahrenkrug says could take a couple of years at least.

The public may weigh in as well, and it’s not known yet what sort of opposition his gene-editing technique might face.

  • Craig Laughlin

    This technology is a real game changer. With respect to the agricultural applications, the company focuses on replicating naturally occurring mutations already present within the genome of a species (i.e., editing the “horns gene” in Holsteins to match the 500 year old genetic mutation found in Red Angus that expresses as “no horns”). The technique should therefore be viewed as nothing more than a benign refinement of the selective breeding process – after all, we’ve been eating meat from hornless beef cattle for half-a-millennium. Furthermore, Holstein breeders have succeeding in moving the hornless trait into the breed through selective breeding, but the offspring just don’t give milk like a purebred Holstein because of the unwanted traits that get dragged along in the process. So milk from cows with this particular mutation is already being consumed by humans with no ill effects, the cows are just not great milkers. The gene-edited Holsteins, however, will produce more milk and will be genetically identical to their ancestors, except that they simply won’t have horns. [Full disclosure: I am an investor (and believer) in this company.]