Video: Genetically edited dairy cows raised at UC Davis
The two calves that grace a muddy pen on the UC Davis campus will never grow horns typical of their breed. Instead, they’ll always sport soft hair on the parts of their heads where hard mounds normally emerge.
Named Spotigy and Buri, the calves were designed in a petri dish at a Minnesota-based genetics lab, with the goal of making them easier to pack into pens and trucks without the nuisance of their horns taking up valuable space. Their offspring may also lack horns, and generations of hornless cows could follow, potentially saving the dairy and cattle industry millions of dollars, said Alison Van Eenennaam, a geneticist at UC Davis’ College of Agriculture and Environmental Sciences who worked with the Minnesota lab Recombinetics.
This first-of-a-kind result of a process called genetic editing is a test run that’s expected to deeply impact the cattle and dairy industry and the entire food supply, Van Eenennaam said. It’s also part of a flurry of research looking at how to make cattle easier to maintain, transport and turned into food. The research has raised concerns among some farmers and animal-rights activists who warn of the health and ethical risks of consuming genetically modified food, but so far, that hasn’t stopped the research drive.
At UC Davis, animal geneticist Pablo Juan Ross has been trying to perfect a technique developed a decade ago but now gaining more acceptance to design cattle that produce only male offspring.
“Males grow faster than females, and in beef production they are more desirable,” Ross said.
Another project uses stem cells to produce a clone animal, Ross said. Genetic editing could also help design cows that are less prone to pneumonia, which would reduce their need for antibiotics.
Van Eenennaam is keen on using word processing as an analogy to describe the differences between genetic editing and engineering. She likens genetic editing to changing the spelling of a word within a document and genetic engineering to pasting in a word from a completely different document.
“You’re not bringing in something foreign ... like introducing a protein from a tomato into a fish, which is what is associated in genetic engineering,” she said.
With the two dairy calves, a precise section of DNA responsible for horn growth was knocked out and replaced with a precise section from a cow that does not produce that trait. Many cattle varieties do not grow horns, including Angus cattle. With dairy cattle – both male and female – horns are a given, and the animals are dehorned soon after they’re born.
Once the cows are sexually mature, Van Eenennaam will collect semen from the bulls to inseminate horned cows – the route by which most cows are impregnated in the cattle and dairy industry. The plan is to track the calves’ growth and development and see whether the two faithfully transmit the hornless trait to their offspring.
“The odds are 100 percent if Mendelian genetics holds true,” she said.
She added that it’s not clear whether other, unexpected effects of editing will appear. If successful, it will allow the industry to bypass decades of breeding for polled, or hornless, cows.
Oroville cattle rancher Megan Brown raises polled Herefords, which she purchases dehorned. Those animals were selectively bred for that trait, but the demands of breeding a cow reduce a cow’s dairy output.
“I’d definitely buy the gene-edited cows” over the bred variety, Brown said.
She also sees polled cows as a big safety improvement. “We’d always have cows trying to gore us,” she said.
Typically, the horns are cut out out of the animal, which can involve heavy expenses and lots of suffering for the animals. “The cost of dehorning can be a lot, especially if the cow gets an infection from the removal and dies,” Brown said.
At the University of Missouri, researchers focus on genetically modifying pigs to remove genetic traits for maladies such as retinitis pigmentosa, hemophilia and cystic fibrosis, said Randall Prather, an animal geneticist at the school.
“Until now, physicians had nothing until we made these pigs,” Prather said. “There was nothing to experiment on except kids that had cystic fibrosis. Now they can go in and monitor the progression of this disease and come up with treatment and cures that you couldn’t try on humans first.”
The Australian-born Van Eenennaam makes no apologies for genetic editing in a state where genetically modified food has been a hot-button issue. She bristles at the notion that genetically modified organisms bring health risks.
In fact, she believes genetic editing can be as good for animal health as it is for the food supply. Scientists at Washington State University have already identified a gene edit that makes cows less susceptible to respiratory disease. Some of those cows that carry the edited gene in utero are scheduled to be shipped to UC Davis in 2016, although the university has not yet received the funding to continue that research.
Pneumonia is no small matter in the cattle industry. An estimated 16 percent of cattle in feedlots show signs of respiratory disease at some point during the feeding period, a U.S. Department of Agriculture study found in 2011.
USDA data show that nearly a third of all cattle deaths are due to respiratory issues and peg the cost to producers at $643 million annually.
“The public ... will consume animals who may have never been sick,” Van Eenennaam said.
She said genetic editing also offers an environmental benefit, especially with cow-produced methane identified as a significant contributor to global climate change. “When you’re able to breed animals that are healthier and better suited to the environment,” she said, “you need less of them to produce the same amount of product.”
Edward Ortiz: 916-321-1071, @edwardortiz