The unsurpassed efficiency of CRISPR technology helps to sustain animal health and welfare through reducing the number of animals sacrificed. CRISPR tools are also used to create animals that are genetically designed in a more sophisticated fashion. In vitro technologies should ideally be complemented by animal studies. We previously  claimed the benefits of refining guide RNAs in CRISPR technology and we, as researchers who are engaged in producing and using model mice on a daily basis, also support the welfare and health of animals.
Source: Bio Technology