What To Do
Assess the horse's general health using the Whole Horse Exam (WHE), paying particular attention to their attitude and appetite. Watch them for awhile to see if they are urinating and passing manure normally.
Gently lift the tail and feel and view its full length looking for signs of any abnormality. Raise and lower it. Move it side to side. Feel the muscle and ligament that joins the tail to the hip, the sacrum. Be very careful when handling the tail because manipulation may cause a horse pain. Examine the anal and vulvar area looking for any abnormalities, including injuries or skin conditions.
Share your findings and concerns with your vet.