Health disorders caused by feeding are a common problem in cattle keeping. For this reason the personal computer program, FURAT, was developed for the calculation and optimization of ruminant feed rations with respect to physiological aspects. With this program, weighed feed rations selected from the feedstuff on the standard list or from a self-drawn up feedstuff list can be tested for their content of various nutrients and compared with the requirements of the animals to be fed. Subsequently in an optimization program using the same feedstuff rations can be worked out for various performance categories ensuring the best possible feeding from the health aspect. With a free choice within a feed range and taking into account the physiological limits of the rumen (maximum compound intake, minimum raw fiber amount in the dry matter, minimum structure in the raw fiber, maximum raw fat in the dry matter) the ration is calculated to achieve a balanced protein-energy ratio. One of the two main nutrients--protein or energy--must amount exactly to the target value in the ration, and the other has to be as close as possible to its target value. From among up to 12 different feedstuff the computer will choose the optimal ration which can be printed with a precise indication of all parameters. The rations worked out for the various performance categories are stored and, at the end of the program, are printed in short form in a letter addressed to the farmer that also lists necessary mineral supplements.