The adult male cattle is called a bull.
A bull is a male cattle that has reached adulthood and is used for breeding and for producing beef. Bulls are typically larger and stronger than cows (female cattle) and have distinctive characteristics such as horns and a hump on their shoulders. They play an important role in the agriculture industry, as they are used for breeding to produce more cattle for dairy, beef, and other agricultural purposes.
Ram is a term used for adult male sheep, while boar is a term used for adult male pigs. Duck is a type of waterbird and not a type of cattle.