What you see. The starting point for addressing any equine health related issue is your observation.


Lump, Bump, Growth on Shaft of Tail


Hard lumps and bumps in this area may result from infected wounds or abscesses. If the horse is a gray, a hard bump here is melanoma until proven otherwise. Fractures can also cause hard lumps on the tail. A quickly growing mass here in a non-gray horse can be a form of melanoma.

  • Code Orange

    Call Your Vet at Their First Available Office Hours
    • If the mass is large, painful or seems to be growing rapidly.
  • Code Yellow

    Contact Your Vet at Your Convenience for an Appointment
    • If you consider this a chronic and relatively mild problem that is not changing rapidly.

your role


What To Do

Assess your horse's general health using the Whole Horse Exam (WHE), examine the area, and take a photo of it to send to your vet. Feel the area for swelling, redness, or a pain response. Is the lump hard or soft? How large is the lump?

If the horse is a gray and a melanoma is suspected, a dated photo provides a baseline for comparison later. Check the other common areas where melanomas develop, around the anus, on the sheath, behind the jaw, and within the tissue of the lips. If the horse is a non-gray then it is important to get veterinary evaluation quickly. Share your findings and concerns with your vet.

your vet's role

Your vet will evaluate the area and may suggest a biopsy or treatment, depending on the characteristics of the mass, and their approach.
Questions Your Vet Might Ask:
  • When did you first notice this problem?
  • Is the horse a gray horse?
  • Has the swelling changed in size and character since you first noticed it?
  • What are the results of the Whole Horse Exam (WHE)?

Author: Doug Thal DVM Dipl. ABVP