The effects of chiropractic, massage and phenylbutazone on spinal mechanical nociceptive thresholds in horses without clinical signs

Equine Vet J. 2008 Jan;40(1):14-20. doi: 10.2746/042516407X240456.


Reason for performing study: Common methods used to treat back problems in horses need to be assessed objectively.

Objectives: To measure spinal mechanical nociceptive thresholds (MNTs) and evaluate the effects of chiropractic, massage and phenylbutazone, compared with active and inactive control groups.

Methods: Baseline MNTs at 7 sites within the thoracolumbar and sacral regions were measured in 38 healthy mature horses exhibiting no clinical signs of lumbar pain. Horses were assigned to one of 3 treatment groups: instrument-assisted chiropractic treatment, therapeutic massage and phenylbutazone; or 2 control groups: ridden exercise (active control) or routine paddock turnout with no ridden exercise (inactive control). MNT measurements were repeated at 1, 3 and 7 days post treatment. The percentage change from baseline MNT values was calculated within groups.

Results: On Day 7, the median MNT had increased by 27, 12 and 8% in the chiropractic, massage and phenylbutazone groups, respectively. MNT changes of <1% were seen within the active and inactive control groups.

Conclusions: Chiropractic treatment and massage therapy increased spinal MNTs within horses not exhibiting signs of lumbar pain.

Potential relevance: Pressure algometry provides an objective tool to evaluate the effects of commonly used, but currently unproven treatment modalities on spinal MNTs. Future studies need to evaluate combined treatment effects and longer-term MNT changes in horses with documented back pain.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Animals
  • Anti-Inflammatory Agents, Non-Steroidal / therapeutic use
  • Back Pain / drug therapy
  • Back Pain / therapy
  • Back Pain / veterinary*
  • Biomechanical Phenomena / methods
  • Combined Modality Therapy / veterinary
  • Female
  • Horse Diseases / therapy*
  • Horses / physiology*
  • Lumbar Vertebrae / physiology
  • Male
  • Manipulation, Chiropractic / methods
  • Manipulation, Chiropractic / veterinary*
  • Massage / methods
  • Massage / veterinary*
  • Nociceptors / physiology
  • Pain Threshold / physiology*
  • Phenylbutazone / therapeutic use*
  • Physical Conditioning, Animal / physiology
  • Pressure
  • Thoracic Vertebrae / physiology
  • Treatment Outcome
  • Weight-Bearing / physiology


  • Anti-Inflammatory Agents, Non-Steroidal
  • Phenylbutazone