Trace minerals (TMs) are pivotal for animal wellbeing and appearance. This study evaluated the effects of TM (Zn, Mn, Cu, and Fe) sources on senior dogs' haircoat and activity. Dogs (mean age 9.16 yr) were fed a control diet (inorganic TM) for 14 d before being assigned to one of three treatments for 3 mo. Treatments included inorganic (Control