The 21st Annual “Distinctly Different”
Angus Bull Sale
Feed Efficiency Definitions
Average Daily Gain (ADG): The rate of weight gain per day over a specified period of time. For example, if a bull
weighs 1,000 pounds on January 1 and weighs 1,100 pounds on February 1 of the same year, then he gained 100
pounds in 31 days. Divide 100 pounds by 31 days, and the ADG is 3.2 pounds per day.
Feed Conversion Ratio (FCR): The dry matter intake divided by weight gain. For example, if a bull ate 18 pounds of feed per day on a dry matter basis, and gained 3 pounds per day, his FCR would be 18 divided by 3 = 6 pounds of feed per 1 pound of gain.
Residual Feed Intake (RFI): The difference between actual feed intake and predicted feed intake based on an animal's gain, body weight and composition. For example, if a bull actually eats 22 pounds of feed per day, but is predicted to eat 24 pounds of feed per day, his RFI is 22 minus 24 = -2.00 pounds of feed per day. Negative RFI is favorable. RFI is independent of growth and mature size, so by selecting for RFI we are not inadvertently selecting for larger mature cattle.