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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.
These efficiency measures are not correlated to one another and thus selection
on one lone efficiency ratio will not mean the most efficient choice. A balance
of efficiency traits would be suggested.
