A commonality shared by many of those writing from science studies perspectives – especially sociology, political economy and anthropology – on genomics and the biosciences is an interest in the notion of promise. e conceptions of biocapital discussed in the previous chapter posit the practices of genomics, its rationale and communication, as promissory knowledge claims. As the science of genomics is worked through and presented, it is inseparable from this promissory context. is way of thinking about a ‘promising’ technology – the word switches from adjective to verb – opens up a critical space to think about the fragility of scientic knowledge claims embedded within social, economic and political contexts. is chapter pursues the notion of promise in relation to farm animal genomics, focusing on the positioning of such sciences through a discourse of sustainability. Farm animal genomics is not alone among contemporary biosciences in this positioning – others include marine biotechnology (Helmreich, 2007), GM crops and synthetic biology.1 Two initial points can be made. First, it is important to probe any mobilization of ‘sustainability’, given its nebulous and contested history. And second, it can be argued that such a positioning in the case of farm animal genomics has become precarious given the increasingly publicized link between global livestock production and climate change.