Scientists have collaborated to produce the first gene-edited calf that’s resistant to the bovine viral diarrhea virus, a disease that costs the U.S. cattle sector billions of dollars annually.
Don’t worry, though: GM beef won’t be hitting the shelves anytime soon — this promising trait is still in the research phase.
The scientists first tested this idea in cell culture. After seeing promising outcomes in the laboratory, Acceligen scientists edited cattle skin cells to develop embryos carrying the altered gene. These embryos were transplanted into surrogate cows to test whether this approach might reduce virus infection in live animals.
Over the past 20 years, the scientific community discovered the main cellular receptor (CD46) and the area where the virus binds to that receptor, causing infection in cows. Scientists modified the virus binding site in this recent study to block infection.
It worked. The first CD46 gene-edited calf, Ginger, was born healthy on July 19, 2021. The calf was observed for several months and then later challenged with the virus to determine if she could become infected. She was housed for a week with a BVDV-infected dairy calf-born shedding virus. Ginger’s cells displayed significantly reduced susceptibility to BVDV, which resulted in no observable adverse health effects.
Scientists will continue to closely observe Ginger’s health and ability to produce and raise her calves.
Aspen Workman, the lead author and researcher at the U.S. Meat Animal Research Center in Clay Center, Nebraska, said, “Our objective was to use gene-editing technology to slightly alter CD46 so it wouldn’t bind the virus yet would retain all its normal bovine functions.”
The recent study published in PNAS Nexus results from a collaboration between the USDA’s Agricultural Research Service, the University of Nebraska–Lincoln, the University of Kentucky, and industry partners, Acceligen and Recombinetics, Inc.
Why is BVDV important to address?
BVDV is one of the most significant viruses affecting the health and well-being of cattle worldwide, and researchers have been studying it since the 1940s when it was first recognized.
This virus does not affect humans but is highly contagious among cattle and can cause severe respiratory and intestinal diseases. In particular, BVDV can be disastrous to pregnant cows because it can infect developing calves, causing spontaneous abortions and low birth rates.
Some infected calves survive to birth and remain infected for life, shedding massive amounts of virus to other cattle. Despite over 50 years of vaccine availability, controlling BVDV disease remains a problem since vaccines are not always effective in stopping transmission.
This proof-of-concept study demonstrates the possibility of gene editing reducing cattle’s burden of BVDV-associated diseases. The edited calf also represents another potential opportunity to lessen the need for antibiotics in agriculture since BVDV infection also puts calves at risk for secondary bacterial diseases.
Related: ‘Fitbits’ on cows? How technology and health monitoring helps dairy farmers
