Once again......stumbling

[bgoodwin]

5 y/o Racking mare lands toe first. She only stumbles at a walk and usually only flat, or close to, ground. It appears she "knuckles over", and has went to her knees a couple of times. Any help would be appreciated. Also she is very sure-footed in the rack.

[Rick Burten]

Repetitive/continuous toe first landing is one definition of lameness. This may be due to incorrect trimming, conformation issues, or other factors, but always indicates pain, and that pain is generally confined to the rear third of the hoof, with the heel area being the most suspect.

What diagnostics have been performed?

Considering that this horse is having problems at the walk, there is no way I'd work it at speed.