Hooves are barometers, with a time lag. The last time Grace had a jab she had an allergic reaction and it has shown up as a significant event line on her hooves.
I wonder if her tying up yesterday will present itself as another event line in the weeks to come?
This is one of my issues with horse shoes. They don't just cause damage in themselves, they mask the symptoms of other health issues which need addressing, but because the horse is wearing shoes the problems go unrecognised.
With Grace being barefoot I know that if I don't manage her diet properly she will get footy. I can address this quickly and she will recover quickly. Depending on how deliquent her diet was and for how long she might not even get an event line.
But I see horses with countless event lines; indicating a more severe problem, which have not shown any lameness; probably because they are wearing shoes. As the shoes restrict the circulation to the foot, the horse can't feel them properly, so vital feedback is denied.
Which of course is why we shoe horses. It allows us to work animals that are sick and to ignore the consequences.