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.
Beef cattle in the US, an FCR calculated on live weight gain of 4.5–7.5 was in the normal range with an FCR above 6 being typical. Divided by an average carcass yield of 62.2%, the typical carcass weight FCR is above 10. , FCRs had not changed much compared to other fields in the prior 30 years, especially compared to poultry which had improved feed efficiency by about 250% over the last 50 years. 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. Using an FCR calculated just on the weight of protein and fat, an FCR of 13 was poor, and an FCR of 8 was very good. In the dairy industry, feed efficiency (ECM/intake) is often used instead of FCR (intake/ECM); an FE less than 1.3 is considered problematic.
Pigs Pigs have been kept to produce meat for 5,000 to 9,000 years. , pigs used commercially in the UK and Europe had an FCR, calculated using weight gain, of about 1 as piglets and ending about 3 at time of slaughter. , in Australia and using dressed weight for the output, a FCR calculated using weight of dressed meat of 4.5 was fair, 4.0 was considered "good", and 3.8, "very good". The FCR of pigs is greatest up to the period, when pigs weigh 220 pounds. During this period, their FCR is 3.5. 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. 5 to 6 on some forages of good quality, and more than 6 on feeds of lesser quality. On a diet of straw, which has a low metabolizable energy concentration, FCR of lambs may be as high as 40. Other things being equal, FCR tends to be higher for older lambs (e.g. 8 months) than younger lambs (e.g. 4 months). For hens used in egg production in the US, the FCR was about 2, with each hen laying about 330 eggs per year. When slaughtered, the world average layer flock as of 2013 yields a carcass FCR of 4.2, still much better than the average backyard chicken flock (FCR 9.2 for eggs, 14.6 for carcass).
Carnivorous fish In
aquaculture, the fish feed for carnivorous fish commonly includes fish-derived products in the form of
fishmeal and
fish oil. There are therefore two ratios to be reported: • The regular feed conversion ratio, i.e. output fish mass divided by total feed mass. • The conversion ratio only taking into account the fish-based component of fish feed, called the FIFO ratio (or Fish In – Fish Out ratio). FIFO is fish in (the mass of harvested fish used to feed farmed fish) divided by fish out (mass of the resulting farmed fish). FIFO is a way of expressing the contribution from harvested wild fish used in aquafeed compared with the amount of edible farmed fish, as a ratio. The fish used in fishmeal and fish oil production are not used for human consumption, but with their use as fishmeal and fish oil in aquafeed they contribute to global food production. Fishmeal and fish oil inclusion rates in aquafeeds have shown a continual decline over time as aquaculture grows and more feed is produced, but with a finite annual supply of fishmeal and fish oil. Calculations have shown that the overall fed aquaculture FIFO declined from 0.63 in 2000 to 0.33 in 2010, and 0.22 in 2015. In 2015, therefore, approximately 4.55 kg of farmed fish was produced for every 1 kg of wild fish harvested and used in feed. (For Salmon & Trout, the FIFO ratios for 2000, 2010, and 2015 are: 2.57, 1.38, 0.82.) farm-raised
Atlantic salmon had a commodified feed supply with four main suppliers, and an FCR of around 1.
Tilapia is about 1.5, and farmed
catfish had a FCR of about 1.
Herbivorous and omnivorous fish For herbivorous and omnivorous fish like
Chinese carp and
tilapia, the plant-based feed yields much lower FCR compared to carnivorous kept on a partially fish-based diet, despite a decrease in overall resource use. The edible (fillet) FCR of tilapia is around 4.6 and the FCR of Chinese carp is around 4.9.
Global averages by species and production systems In a global study,
FAO estimated various feed conversion ratios, taking into account the diversity of feed material consumed by livestock. At global level, ruminants require 133 kg of dry matter per kg of protein while
monogastrics require 30 kg. However, when considering human edible feed only, ruminants require 5.9 kg of feed to produce 1 kg of animal protein, while monogastrics require 15.8 kg. When looking at meat only, ruminants consume an average of 2.8 kg of human edible feed per kg of meat produced, while monogastrics need 3.2 kg. Finally, when accounting for the protein content of the feed, ruminant need an average of 0.6 kg of edible plant protein to produce 1 kg of animal protein while monogastric need 2 kg. This means that ruminants make a positive net contribution to the supply of edible protein for humans at global level. == Feed conversion ratios of meat alternatives ==