Gene editing technology produces first BVDV-resistant calf 

For decades, the deadly bovine viral diarrhea disease has been troublesome to dairy and beef producers, as vaccination has been the only thin shield to ease the effects of the virus.

• READ MORE: Gene-edited pigs show resistance to PRRS

Recently, U.S. Department of Agriculture (USDA) scientists have created the first gene-edited calf with resistance to BVDV with the help of CRISPR, a gene-editing tool. Scientists modified the gene cell (CD46), which binds the virus to that receptor and causes infection in cows.

"Our objective was to use gene-editing technology to alter CD46 slightly so it wouldn't bind the virus yet would retain all its normal bovine functions," says Aspen Workman, lead author and researcher at USDA Meat Animal Research Center in Clay Center, Nebraska.

After seeing promising results in cell culture, the team edited cattle skin cells to develop embryos of the altered CD46 gene, then transferred them to surrogate cows to test if this would reduce virus infection in live cows.

In July 2022, the first CD46 gene-edited calf was born. Workman and her team observed Ginger for several months before testing her genetic prowess by pairing Ginger with an infected dairy calf shedding the virus.

As a result, Ginger had reduced susceptibility to the virus and had no adverse health effects. Still, scientists continue to observe Ginger's health and ability to produce and raise calves.

While this is a promising future trait for the U.S. cow herd, gene-editing BVDV-resistant cattle is still in the research phase and will only enter the food supply once more research has been done, says Workman.

• READ MORE: FDA clears CRISPR cattle for meat production

Many cow herds still struggle with BVDV, as there are more than 1,215 cases in the United States, according to the Boehringer Ingelheim Animal Health BVDV tracker.

A recent national survey from Boehringer Ingelheim Animal Health found that 81% of beef and dairy farmers vaccinate for BVDV, the only actual defense farmers have against the disease.

The survey found that most farmers also vaccinated their herds with a modified live virus to protect health and prevent persistently infected (PI) calves, which is the typical way the virus is spread in a herd.

"We know that a newborn calf has a very functional immune system. It's naïve and immature but functional," says Tim Parks, a technical services veterinarian with Merck Animal Health. "We vaccinate animals to stimulate the immune system so they are prepared when they come up against a health challenge."

• READ MORE: China approves safety of first gene-edited crop

Each day a calf gets older, the more responsive the immune system becomes, especially if that calf is prepared for a challenge like BVDV.

"If we can stimulate the immune system and create antibodies, we can create an immunological memory, and the calf will better be equipped to fight the disease," adds Parks.