Re: Question - laminitis or too much trim?
You've done a lot of good things to get your girl into an overall better place. Now you need to fine tune things so that they are optimal instead of just "better".
Allowing grazing for an IR horse is playing Russian Roulette with her health. A Greenguard muzzle is not suitable to keep an IR horse safe if turned out on grass as it won't prevent her from eating the grass. It doesn't sound as if you've had the hay actually mineral balanced - which means her diet isn't as tight as it could be. Whether the Amino Trace Plus is a good fit for her hay or not is an unknown. Do you have a copy of the current hay analysis that you could share?
The timing of the soreness makes it suspicious for the trim being at least part of the problem. Trimming off frog from a barefoot horse is generally unnecessary, except for isolated ragged spots. Scraping off sole is also not needed as a barefoot horse will shed exfoliating sole on its own. August and May lameness incidents in an EMS/IR horse also coincide with times when insulin tends to spike due to ACTH increases heading into the fall (August) and spring grass growth. It could be that the trim pushed her over the edge if she had some sole removed while she was also spiking insulin due to the increased grazing time - perfect storm of problems occurring at once. Being more sore on one foot can point to a possible abscess that may have been mobilized due to the trim. It would be really helpful to see a full set of current hoof pix so we can see what is happening with her trim as the last ones were from over a year ago. Here's the link to what photos would help:
Lavinia, George Too, Calvin (PPID) and Dinky (PPID/IR)
Nappi, George and Dante Over the Bridge
Jan 05, RI