Sciences related to animal agriculture are threatened by agenda-driven scientists. It can be shown that too many peer-reviewed articles have dubious quality, including high-profile ones. Better training and higher review standards for rigour, reproducibility and transparency should help alleviate the problem. However, they will not solve the challenge posed by 'cargo cult scientists', as characterised by Richard Feynman. Such agenda-driven scientists pursue an a priori mission, whose achievement justifies any means, even if it includes to willfully manipulate and interpretate data, or to violate good practices of integrity in the sciences. This review explores in three prominent case studies in animal-sourced food related sciences where the dividing line might be between science being poorly practiced (which can be remedied), and scientific channels being abused for agendas (which should not be tolerated). So as to guard both as the individual scientist and as the discipline against the intrusion of such agenda-driven science, this article suggests adopting the Popperian stance to generally refrain from the concept of seeking or establishing a 'scientific truth', and instead to restrict oneself to presenting the 'scientific evidence', both in terms of what the evidence shows, and what it does not.