Gene editing's successful application to benefit farm animals' welfare is unlikely in the short to medium term, particularly in low- and middle-income countries (LMICs), given the high costs and low rates of success to date in research settings.
Reasons: 1. Gene editing is biased toward outcomes that can be easily measured and assessed. More complex traits associated with animal welfare such as behavior or condition are less likely to be targeted using gene editing. 2. Gene editing has been designed for use in vertically integrated production systems as livestock breeding is centralized and breeds themselves are highly standardised in these systems. Many LMICs lack vertically integrated production systems, have higher numbers of smallholder farmers, lack investment by companies and NGOs to promote these technologies, lack gene editing researchers, and have limited local support for biotechnology research and training.
Potential downsides of gene editing: 1. Where the intensification of livestock production is growing, gene editing is likely to further accelerate intensification and disadvantage farmers relying on less intensive production systems. 2. Genetic diversity across traditional breeds is valuable and should be maintained. It is not clear how gene editing could affect this diversity.
There may be specific applications that could lead to improvements in animal welfare in certain LMICs, for example: 1. Using gene editing to bias sex ratios could be particularly valuable in India, given the country's extensive dairy industry. 2. Sex selection in layer hens in Egypt, given hens there are raised in an increasingly vertically integrated production system. 3. Producing polled cattle and eliminating the need for mechanical dehorning as currently occurs in many locales.
Many farm animal welfare issues in LMICs are less likely to be addressed through applications of gene editing as opposed to lower technological measures such as better access to veterinary services, better management practices, improved biosecurity, and poverty reduction.