FEMORAL BONE MICROMORPHOLOGY: A COMPARATIVE STUDY BETWEEN WILD (Ovis aries musimon) AND DOMESTIC (Ovis aries aries) SHEEP.

The mouflon (Ovis aries musimon) and the sheep (Ovis aries aries) are the wild and domestic subspecies of the same species. In spite of some different phenotypic features, such as coat color and horn morphology, their skeletons are very similar, so distinguishing bones between these two subspecies is not easy. In this work, mouflon bone micromorphology was studied for the first time and compared to the domestic subspecies, in order to highlight the role played by the lifestyle on bone with special regard to secondary osteon morphology and morphometry. Area, perimeter, minimum and maximum diameter of more than 200 secondary osteons and Haversian canals were measured in cross sections of four adult femurs from each subspecies. Qualitative investigation of bone histology revealed plexiform and irregular Haversian tissue in both subspecies, as previously reported for Ruminants. In addition, the mouflon showed the presence of several secondary osteons clustered in small groups in many regions, which may be consistent with the definition of dense Haversian tissue. Quantitative analysis demonstrated that mouflon secondary osteons are larger than in the sheep and made of a higher number of lamellae (5-7). The wide areas characterized by dense Haversian tissue frequently found in mouflons, as well as the larger dimensions of secondary osteons may be consequent to the habits of wild life typical of that subspecies.