In animal husbandry, feed conversion ratio (FCR), feed conversion rate, or feed conversion efficiency (FCE), is a measure of an animal's efficiency in converting feed mass into increases of the desired output. For dairy cows, for example, the output is milk, whereas animals raised for meat – such as beef cows, pigs,chickens, and fish – the output is the mass gained by the animal. Specifically FCR is the mass of the food eaten divided by the output, all over a specified period.