Just wondering how do you do it?
I was taught to watch the head movement, but does it always work? I mean if head moves normaly then horse definitely isn't lame?
Does the head move differently if horse is limping on hind leg too?
So it doesn't depend only on the head/hip dropping, if limping is not so noticable it's possible that there won't be head/hip dropping?
Last year I couldn't figure out which leg it was, because there was no unusual head/hip moving, but something didn't seem right... I helped myself with moving my legs in the same rythm as horse and then asking myself which leg hurts :P (I was trying to find out which leg is loaded less as Alwaysbehind said, but I can't do it just by watching)
I wondered if there was an easier to tell, but it doesn't seem so.
Another thing that makes lameness a bit tricky is if they have bilateral lameness. Navicular, arthritis, and OCD are just a few of many diseases that occur bilaterally and if the pain is approximately equal then you will be very hard pressed to see outright limping unless you do a nerve block on one leg. With this in mind trotting them on a hard, level surface on a stright away and on a circle (in both directions) can give you some hints as to what is happening.
You can also look at the limb flight, fetlock dropping, do flexion and extension tests (usually done by a vet) to exacerbate lameness.
The head bobbing can also be difficult as a horse can drop its head when the lame hind leg hits the ground (i.e. Opposite to what happens with a front let).
One of the best things to do is take a video from as the horse is being trotted past you, away from you and towards you which then allows you to look in detail/over and over/slow motion to try and spot the lameness. Posted via Mobile Device
I am not so good at the lameness diagnosis, but I look for the leg that moves faster. Only in the case of unilateral lameness (one leg on one side) So , if right rear leg moves faster , then the left rear is likely the Off leg. He moves the one leg faster because he wants to get it back to taking weight as quick as possible so that he can reduce the amount of time that the bad leg must bear weight.