Researchers Select For Horn-Free Trait in Dairy Cattle

Scientists discover gene-editing technique to produce horn-free dairy cattle genetics

Published on: Sep 18, 2013

Researchers at the University of Minnesota have discovered a gene-editing technique that may do away with the hassle and cost of dehorning dairy animals.

The technique is similar to selective breeding, but this uses genetic markers and speeds the process. To select for hornless animals specifically, scientists transmitted genetic variants from Red Angus to Holstein to create dairy cattle without horns.

Farmers typically dehorn to avoid injury to handlers and other animals.

"We demonstrated that a sequence associated with horns in dairy cattle could be converted to a natural beef cattle variant that is hornless, providing a strategy to improve animal welfare by genetic instead of physical or chemical dehorning," Fahrenkrug says.

Scientists discover gene-editing technique to produce horn-free dairy cattle genetics
Scientists discover gene-editing technique to produce horn-free dairy cattle genetics

"Livestock genomes are made up of about 3 billion letters (A, G, C, T)," he says. "We showed we could change one letter of the genome in livestock cells without changing anything else."

The results suggest that gene editing can be incorporated into selection programs to accelerate genetic improvement when selective breeding is either inefficient or impossible, Scott Fahrenkrug, associate professor of animal science in the College of Food, Agricultural and Natural Resource Sciences and study author said.

"The platform promises to revolutionize livestock genetics by accelerating breeding," he says. "What traditionally (by selective breeding) takes eight generations (24 years in cows) can now be accomplished in a single generation by gene editing."

Enabling the use of livestock traits will likely enhance animal welfare, health, sustainability and efficiency of protein production, all while decreasing environmental impact. It will also have positive implications for human health, researchers believe.

Collaborators on the paper include Perry Hackett, professor in the department of genetics, cell biology and development and the team from Recombinetics, a company created in 2009 to commercialize technology created at the University of Minnesota.

Read the paper online at www.pnas.org.