TENS stands for Transcutaneous Electrical Nerve Stimulation

TENS is a non-invasive, safe nerve stimulation intended to reduce pain, both acute and chronic. While controversy exists as to its effectiveness in the treatment of chronic pain, a number of systematic reviews or meta-analyses have confirmed its effectiveness for postoperative pain, osteoarthritis, and chronic musculoskeletal pain. In palliative care and pain treatment, TENS units are used in an attempt to temporarily alleviate neuropathic pain (pain due to nerve-damage).

TENS has not been used in horses on a frequent basis, but at the EASMC we are running some experimental trials for chronic pain treatment with TENS. The first results are amazing, horses seem to like the treatment when they got used to it (takes 1-2 days).

Also for horses that are tight in their top line muscles TENS treatment seems to do a great job for relaxing the contracted muscles before a workout session.
When a nerve is damaged, recovery of that nerve and conditioning of the muscles which are innervated by the nerve is a great way to use TENS.
Applying TENS treatment to horses is relatively easy to learn, we instruct clients how to use the TENS-unit and then treatment can be applied at home by the handler on a daily basis with very low costs.