One of the objects that can be crafted and added to a settlement is the heads of a brahmin mounted on a plaque.
A brahmin feed trough can be crafted in a settlement, and will cause the brahmin to stay close to the trough. Having brahmin on the trough will improve productivity, hence increasing food output rate into the workshop inventory. They also produce fertilizer - a component for chemistry. One can only have one brahmin producing fertilizer per settlement, so one only needs one trough.
Kelly will sell a brahmin to the player character for 100 caps. The player character will need to choose a settlement to send the brahmin to. This can be done multiple times.
Once the Starlight Drive In has been won over by the Sole Survivor, brahmin will eventually appear on their own.
Brahmin in some occasions may end up in a player character's built house or in a pre-existing house. This can be problematic as when they do get inside they can block doorways and entry.
Some settlement brahmin drop a synth component upon death.
When a brahmin is attacked in one of your settlements, the settlers will turn aggressive against you. Going away and returning after 24 hours will make the settlers become passive again.
