 Most schemes use a calculation based on the weight of the animal.Some use figures for animals of different sizes which are directly proportional to their weight – for example the 2006 UK Government scheme uses a figure for ruminants of the animal's weight (in kilogrammes) divided by 650.Others include an adjustment for the proportionally higher metabolic rate of smaller animals, according to Kleiber's law, which states that the metabolic rate of most animals varies according to their weight raised to the power of approximately 0.75.