FCR is widely used in hog and poultry production, quail meat protein FE is used more commonly with cattle. Animals that have a low FCR are considered efficient users of feed. However, comparisons of FCR among different species may be of little significance unless the feeds involved are of similar quality and suitability.

As of 2013 in the US, an FCR calculated on live weight gain of 4. 5 was in the normal range with an FCR above 6 being typical. Divided by an average carcass yield of 62. The dairy industry traditionally didn’t use FCR but in response to increasing concentration in the dairy industry and other livestock operations, the EPA updated its regulations in 2003 controlling manure and other waste releases produced by livestock operators. In response the USDA began issuing guidance to dairy farmers about how to control inputs to better minimize manure output and to minimize harmful contents, as well as optimizing milk output.

In the US, the price of milk is based on the protein and fat content, so the FCR is often calculated to take that into account. Pigs have been kept to produce meat for 5,000 to 9,000 years. The FCR of pigs is greatest up to the period, when pigs weigh 220 pounds. During this period, their FCR is 3. Their FCR begins decreasing gradually after this period. Because FCR calculated on the basis of weight gained gets worse after pigs mature, as it takes more and more feed to drive growth, countries that have a culture of slaughtering pigs at very high weights, like Japan and Korea, have poor FCRs.