The last time Red trotted under saddle was September 11, and he'd started to feel not right on September 10. Before that his rehab had been proceeding well. When we looked closely, he had some neurological symptoms again, particularly involving the left hind. Since then, we've been hand walking and walking under saddle, and he's had treatment for another suspected EPM episode - either a new infection or an inflammatory episode linked to having had EPM previously. I've been doing lots of massage on his left hind, which he seems to enjoy, and his neuro signs are all gone. The only deficit he still has is some weakness in the left hind, particular when he has to extend it forward while tracking right. In my massage, I've been paying particular attention to the area of the Achilles tendon bundle above the hock and the set of muscles above it running up next to the tailhead along the back and inside of the hind leg - tightness in this area can restrict forward motion of the leg, and also to the biceps femoralis muscle, which is the big muscle on the side of the hindquarters that has a major role in extending the hind leg forward - he has some slight muscle wasting in this area and I believe this is the muscle area that tires most readily when we work.
The day before yesterday, he was trotting very sound to the left on the lunge, even in the fairly deep new footing of the arena, and still somewhat short-strided with the left hind when trotting right, although very willing to move out - he had some trouble getting that left hind all the way farther forward to make the outside of the arc, but did improve as we lunged and he put more energy into it. After our walk ride in the afternoon, I was able to lead him down the very steep hill to the pasture and he was able to walk down it without dragging his hind leg, and then we rode out in the pasture for a bit, including up the very steep hill back into the barn.
That was quite a workout for him, and I was interested to see how he'd be yesterday. His leg looked and felt the same when I groomed - no heat, swelling or tenderness. We mounted up, and went to work at the walk. The footing at one end of the arena is particularly deep, but we went down there too at the walk. I worked on having him walking energetically - energy is never much of a problem with Red - and using both hind legs equally, particularly when tracking right. At the end of our session, we tried a bit of trot - he seemed pretty happy about the whole thing. For trot, I stayed in the firmer areas of the arena. We only did a few minutes of trot, on the straight and some half-circles to the left. He felt very good, although he tired very quickly.
Wednesday, our vet/chiro is coming to evaluate him and also to do another blood draw for a second EPM test, to see if there is any change in the antibody levels. This is more a matter of curiosity than anything else, as we're already treating him, but if he tests positive it will indicate whether his problems in September were primarily neurological. The mysteries our horses present us with . . .