The protein requirement of cattle is shown in the tables as a percent of the diet dry matter or as pounds per day. Similar to energy, a cow's protein requirements change throughout the year. The requirement for protein is dependent upon the age of the cow, stage of production, and level of production.

Cattle have a daily requirement for a certain quantity of specifi c nutrients such as protein, calcium, and vitamin A. The necessary concentration of these nutrients in the diet (to meet the animal’s requirement) is then determined by the amount of feed consumed. For example, steer calves gaining 2 lb per day may require 1.6 lb of protein per day.

Cattle protein requirements vary with stage of production, size of the animal, and expected performance. During lactation, larger cattle typically require more pounds of crude protein per day than smaller cattle but as a lesser percentage of their total dry matter intake.