This could be totally un related, or not. I almost
lost my border collie this past winter to a blood disorder. What finally
showed up as a problem was her gums started bleeding. I thought maybe
she had gotten kicked in the mouth by one of the horses. But after a
trip to the vet, all sorts of questions about poison, the vet decided to have
some blood tests run ASAP at the local hospital. The results came back
that almost all the white cells in her blood were missing. So she was
not clotting and starting to bleed out. Long story short she was given a
blood transfusion and is now in good health and going with me on training
rides.
I sure hope this is not what is going on with your
horse. But if the discoloration continues or bleeding starts it might be
something to look into.
