The aim of this study (Longtime Effects from different energy supply to the rumen associated Microbiota of growing goats) was the identification of the bacterial community, that is adherent to the rumen mucosa of young male goats, depending on the feeding ration/regime. For this, a feeding experiment with 3 groups of goats was performed. One group consisted of 5 goats and was fed with hay, the second group contained 6 goats and was fed with hay supplemented with 30% barley and the third group consisted of 6 goats that was fed with hay complemented with 60% barley. After this feeding experiment the goats were euthanized and samples where taken from the ventral and dorsal rumen wall. Samples were washed and fixed with different methods for fluorescence in situ hybridization (FISH) and stored at -20°C. DNA was isolated from three goats (one from each group) followed by a 16S rRNA PCR, cloning and sequencing. The software Mothur was used for sequence analyses and the clones from the 3 goats were classified into 140 OTUs based on 99% 16S rRNA similarity. Members of the kingdom Archaea could not be not found. The clones could be assigned to the phyla Proteobacteria, Bacteroidetes, Actinobacteria, Firmicutes, Spirochaetes, Tenericutes, Fibrobacteres and Synergistetes. The first 4 phyla were found to be the most abundant. The distribution of clones on phylum level as well as genus/species level is distinct. This is most likely explained by the different feeding regimes of the 3 groups. There was a strong increase of the Firmicutes with higher energy ration. Urease genes, as thought to encode a metabolic key function of the epimural microbome, could not be detected. FISH was used to analyze the distribution of the epimural community across the rumen wall in more detail. By comparing 9 to 14 images per goat we found a tendency that the stratum corneum gets desintegrated with increasing grain ration. This process increases the amount of epimural bacteria. Furthermore, it was found that there where larger and more groups of bacteria in the crypts than in the other parts of the villi. These results could be confirmed with HE-images of the same sections.