By taking a muscle biopsy roughly the size of an eraser head under local anesthesia, researchers can then isolate satellite cells following enzymatic digestion of the tissue to separate individual cells. Although I am unsure exactly how bovine satellite cells are isolated, it is likely through a fluorescent- or magnetic- activated cell sorting protocol (FACS or MACS). Essentially, these processes allow for the separation of cell types based [usually] on the proteins present on their surface or other features (size, shape, etc). In this case, both of these methods utilize antibody-based sorting via specific proteins expressed on the surface of the satellite cell, typically a population positive for proteins such as Integrin α7, CD34,CD56, CXCR4, Vcam1, CD82 and negative for Sca1, CD45, CD31, and CD11b [15, 16, 17, 18, 19]. Once sorted, the satellite cell population can be confirmed with immunocytochemical staining for markers such as PAX7 and expanded in vitro.