Join Date: Sep 2009
Location: Taranaki New Zealand.
I am going to be of no help and offer two possibilities, I would start with the shoulder. You may have to get a horse specialist to diagnose a problem in the shoulder as lameness in the shoulder can be very subtle and difficult to pinpoint. If it is the shoulder, or infact any kind of muscle, tendon, sprain/strain then you need to be resting that horse. I recommend magnetic boots for strains and sprains, they really help. Also this is just a personnel opinion okay? But be careful with bute because it masks pain without actually treating an injury and injuries can be exacerbated by over rigorous exercise while the horse feels no pain. If the horse is not in excruciating, unbearable pain then maybe lay off the bute, a small amount of pain will help the horse rest and not put pressure on the injury.
On the other hand the problem with really good doers is that we limit their food which can lead to ulcers. It is not uncommon for ponies that are prone to founder developing ulcers through their owners over zealous weight watching. You said that she is a really good doer and that you have muzzled her thus preventing her from grazing so I would really look at ulcers too if I was you. I sympathize with your food predicament, I struggle with my horse in that regard as well and have to find the balance between filling her foraging requirements while limiting her food intake. This is made harder by the fact that my horse pushes over fences to get to food and would eat till she popped if given half the chance.
So probably no help but those are the two things I would be looking at.