While bulls eat the same diet of grains and grass that cows do, bulls used for rodeo competitions eat a high protein diet supplemented with vitamin B12. Cattle are fed with feedstuffs, a mix of roughage, oilseeds, grains and by-products, such as corn and bakery waste.
For roughage, cattle are usually fed hay, silage and grass. Silage refers to preserved, partially fermented grass or maize. Roughage makes up the bulk of their diet, providing fiber and filler but relatively little caloric energy. It is balanced out by grains, usually corn, barley or oats. As cattle age, their diets include more grain to help them gain weight before being sold on the market. Cattle get the bulk of their protein from oilseeds such as soybeans and canola meal.
The amount and composition that a cow or bull eats depends on the animal's age, weight and lifestyle. Beef cattle are fed to maximize weight gain, while rodeo bulls are kept in peak physical condition. However, rodeo bulls are typically still butchered. In Spain, some restaurants serve bull meat, qualifying that the beef comes from bulls that are removed from the selection process. Because the bulls are killed regardless of the demand for meat, the beef is sold at a low price.