Human nutrition
The protein requirement for each individual differs, as do opinions about whether and to what extent physically active people require more protein. The 2005 Recommended Dietary Allowances (RDA), aimed at the general healthy adult population, provide for an intake of 0.8 grams of protein per kilogram of body weight. A review panel stating that "no additional dietary protein is suggested for healthy adults undertaking resistance or endurance exercise."
Beef cattle
On average, cattle will consume 1.4 to 4% of their body weight daily. There are a range of types of feed available for these animals. The standard text in the United States, "Nutrient Requirements of Beef Cattle", has been through eight editions over at least seventy years. The 1996 seventh edition substituted the concept of "metabolizeable protein" for the sixth edition's "crude protein". In the 20th century, Canadian practice followed the American guidance. Already in 1970, the Food and Drug Administration was regulating pharmaceutical supplements in beef cattle feed such as hormones and prophylactic antibiotics.