Q: My quarterhorse has had a problem with founder and laminitis. His front left coffin bone has stabilized. He also has a thyroid problem, but current medication has that stabilized. My question is, when we do trail ride, which is mainly walking, but some light trotting up hills, he breaks out in severe sweats with little or no riding. When we stop, his front section will go into slight tremors or leg shakes. I am wondering if I should have further testing done, or if this is normal considering his past issues.
A: How old is your horse? Older horses with founder should be considered as potentially having Cushing's disease. These horses will not shed out well, may drink/urinate more, and can have what we used to consider a low thyroid appearance. The disease makes them more prone to repeat founder episodes but can be controlled with medication. These horses do tend to sweat more, too. Have you tried him on pain meds to see if he still shakes? He may not be handling the trail ride well and it is becoming too painful or too tiring. If it is pain related, he should be better on a test dose of bute (discuss extended use with your vet). If the bute helps, he needs further testing to see if the pain is from his foot or someplace else in his leg. Continuing to ride him on the bute can put him at risk for further injury until you know why he is painful.
If the bute doesn't help, he may not be able to handle the work due to his condition. In this case, a good overall exam may help determine his muscle condition and strength. Cushing's horses tend to lose muscle tone. Muscle biopsies can help diagnose underlying problems and should be considered in younger horses. Electrolyte abnormalities in the blood could also cause the shakes but he would likely be a low risk candidate for this. Finally, if his foot is the issue, there are surgeries to help realign the bone in the hoof to make it less painful for him. We do think that the malalignment leads to stress and pain.
By Erin Malone, DVM, University of Minnesota