Hoof tester application - used to determine if there is a pain response
Gait can be defined as a coordinated pattern of repetitive limb movements used in locomotion.
When performing a gait assessment what are you looking at associated with the horses limbs?
Vertical head and pelvic movements
What is the order of foot movement during a walk?
RH, RF, LH, LF
What is the order of foot movement during a trot?
RH-LF, suspension, LH-RF, suspension
In a normal horse, how many times does the head/pelvis move up and down during one complete stride?
Twice (once with each limb)
When does minimum and maximum head height occur?
Minimum - mid-stance
Maximum - just prior to impact of the opposite limb
When does minimum and maximum pelvic height occur?
Minimum - during stance phase
Maximum - at the end of stance phase or 'push off'
What other observations can be made to determine lameness? (But are not as reliable as vertical head and pelvic movements)
Hindlimb protraction - this is when you observe the distance between the ipsilateral fore and hind feet. Greatest hindlimb loading occurs during the first half of stance phase/greatest forelimb loading occurs in the second half of stance phase. The distance between the forelimb and hindlimb will increase if the horse is lame on its hindlimb. By decreasing hindlimb protraction the horse is able to move its hoof impact away from the centre of gravity and reduce loading.
Joint angle changes - flexion/extension of the fetlock joint reflects ground reaction force
Stride length, foot placement, tripping or toe drag
Describe how a head nod can be used to aid in forelimb lameness assessment
"The head will drop when the sound foot lands and will rise when weight is placed on the unsound foot." The downward head movement will be less during stance phase on the lame limb - this is to try and reduce the image and make the limb less weight bearing. The upward head movement will be less after stance phase on the lame limb compared to after the stance phase of the non-lame limb.
With regards to forelimb lameness:
a) the minimum head height will be higher/lower on the lame limb during impact and stance
b) the maximum head height will be higher/lower after stance phase of the lame limb
What will you see with regards to head movement if the horse is experiencing impact pain?
There will be less downward head movement during stance phase of the lame limb/less upward movement after stance phase of the lame limb. You will see a difference in minimum and maximum head height between lame and non-lame limbs.
What is a 'hip hike'?
When there is a difference in minimum pelvic height between the lame and non-lame limbs i.e. greater minimum pelvic height on the lame limb
What is a 'hip drop'?
When the upward pelvic movement will be less after stance phase of the lame limb.
What are some of the limitations of lameness scoring systems?
There can be differences in severity at a walk, trot, lunge, when ridden, etc so these should be graded independently.
There is limited 'granularity' but you can use 1/2 grades. Granularity is important when you wish to document subtle changes e.g. following a nerve block or treatment. However, the more points on the scale the less reliable it will be.
Grading systems should not be used interchangeably so there must be good communication between the vets/farrier/insurance to ensure they are all using the same system