A process of artificial selection:
To separate or kill animals with inferior genetics to remove those genetics from the gene pool of a population so that only the animal with desired genetics may live to procreate the next generation which has a superior gene. This process, over time, will make the population have 'better' traits as a whole.
This phrase became famous by the villain of the game Far Cry 5, Jacob Seed, who used this mentality to produce soldiers who may be strong enough to survive the Great Collapse
Jacob Seed: We allow the weak to dictate the powerful and we are shocked to find ourselves adrift. Now, the Collapse is upon us, and this time the lives of the few outweigh the lives of the many. We will cull the herd. We will do what needs to be done.