The adult male cattle is called a bull. A bull is a mature male bovine animal that is used for breeding and producing offspring. Bulls are typically larger and stronger than female cattle, and they have distinctive characteristics such as large horns and a muscular build.
A ram is a male sheep, while a boar is a mature male pig. These animals are not called bulls, as they are not bovine animals.
A duck is a type of bird, and it is not related to cattle or other domesticated farm animals.