Named Sheep (and maybe other animals aren't effected by /effect command

I Had Some Named Sheep In Creative Mode And One Was Named ffffff The Other Was Named Bobby I GAve All Shepp In The Minecraft World Health Boost 255, And When I Hit One Of Them With A Netherite Sword, It Died, I Hit It With The Sword To Test Out If It Got The Effect Or Not *Note That It may work in other versions, but i don't know how to create a svae in 1.12, or 1.17, etc, etc................