The size distribution of intramuscular adipocytes (Fig. 5) shows the development from 10 to 26 months of age. A shift towards larger adipocytes became apparent in JB except from 14 to 18 months of age and corresponded to the increase of the average adipocyte diameter. In HS however, the shift to larger adipocytes appeared only from 10 to 14 and 14 to 18 months of age. Later, the histograms were similar. In both breeds and at all ages, small, developing cells were detected.