Feed is the largest expense to livestock producers, and this expense is unlikely to decrease in the near future. Producing animals that more efficiently direct dietary energy toward growth and performance is one answer to this problem.
Residual feed intake (RFI) is a measure of feed efficiency that uses advanced statistical methods to take into account multiple growth factors. RFI is defined as the difference between observed and expected feed intakes, where the expected feed intake is calculated based on factors such as average daily gain and backfat.