Robust regulations must be put in place to protect the welfare of farmed animals before genome-editing procedures are approved for commercial livestock, ethicists have warned. Powerful gene-editing techniques have the potential to improve modern farming by making animals resistant to heat and disease, reducing methane emissions and increasing productivity, but the same approaches could also exacerbate animal welfare problems, the Nuffield Council on Bioethics says. Though farms have yet to embrace genome editing for animals, its potential in agriculture has driven intense research efforts around the world, leading to experimental animals that demonstrate the viability of the approach. In September, the UK government announced it would bring forward legislation that would pave the way for some genome editing to be allowed in animal breeding. “There is a need to ensure animal welfare is at the heart of plans to introduce genome editing into farmed animal breeding,” said Danielle Hamm, the director of the Nuffield Council on Bioethics. In a report on the social and ethical issues associated with genome editing in farm animals, the ethicists describe how genome editing could bring real benefits, for example by making pigs resistant to the common porcine reproductive and respiratory syndrome (PRRS) virus, or preventing animals from growing horns that cause injuries to others around them. But other applications could have a major impact on animal welfare, they warn. Elizabeth Cripps, a co-author on the report and a senior lecturer in political theory at Edinburgh University, said a particular concern was the creation of animals that could tolerate poor conditions without it apparently having an adverse health impact. “That could mask the effect that they continue to live in unacceptable conditions,” she said. Another serious concern was the possibility of animals being bred that are no longer physiologically capable of having “a good life”. The ethicists are calling for an “urgent” public discussion before genome editing is approved for commercial farming, and for an independent body to work with breeders and oversee a “traffic light system” that ranks the welfare of farmed animals. Under the scheme, green would mean animals can live a good life in a well-managed husbandry system, amber would mean that further breeding may threaten the animals’ welfare, and red would indicate animals that do not have an acceptable quality of life and should not be used in commercial farming. Bruce Whitelaw, a professor of animal biotechnology at the Roslin Institute where Dolly the Sheep was created, said genome editing had much to offer agriculture. “We have already shown that this technology can reduce the burden of disease in livestock by producing at Roslin pigs resistant to the PRRS virus. If this application progresses to the farm this will have welfare benefits for the animals on that farm,” he said. “It is now timely to have a dialogue to explore how we can use genome editing to benefit agriculture and our food supply. From this, appropriate incentives can be identified which will drive fair and responsible livestock breeding.” Katrien Devolder at the Oxford Uehiro Centre for Practical Ethics said: “Ideally, we would reform farming practices, rather than modifying animals to fit them. But if we can’t achieve the ideal, the best option may be to pursue genome editing while also taking steps to reform factory farming. For example, we could combine genome editing with higher taxes for meat, eggs and dairy from factory farms, or with structural support for the production of lab-grown meat, or alternative and more sustainable farming practices.”