An either inhale or exhale variation of "screaming" used to signify pigs going to the slaughter. This is also known as a pig squeal. They are performed by vocalists in deathmetal/grindcore bands (As Blood Runs Black, Skinless, Job For a Cowboy, Arsonist Get All The Girls etc). The pitch of the squeal can vary. Deathmetal bands tend to keep squeals lower. Grindcore bands usually have them higher. The sound of the squeal refers to it's name "bree".
1. Hey dude, listen to him bree, that's fucken brutal!