Feed intake and digestibility are indicators for the assessment of the nutritive value of feed-stuffs, supply situation of the animal and prevention of related diseases and developmental disorders. Plant and external alkanes can be used to determine feed intake and digestibility. Such markers should not be resorbed, altered or synthetized during gut passage. Nevertheless, faecal recovery is often not complete or too high, which requires a correction and limits the application of the method. Problems with dosing and administration of an external alkane may increase the error of estimation. In three studies, it has been investigated if (1) feed in-take and digestibility can be estimated without a correction as well as (2) the dosing of exter-nal alkanes can be improved and (3) their complete and repeatable ingestion can be assured in horses. Methodical preconditions for application of a marker-based method have been worked out, which also allow the measurement of intake and digestibility in growing horses on pasture. This is an important requirement for an adequate supplementary feeding of grazing horses.