I thought this may be interesting for others to see.
On April 28th I went out in the morning to find Ace looking like this
I was horrified, and called the vet out, I was then even more horrified to get a bill for over $200 just to have her drive out take one look at it, announce that she couldn't stitch it, because it was to old, advise treating with unpasteurized honey, and then she left. Now to be fair it was the weekend, because horses only ever get injured out of hours, anyone else scared this long weekend! It was also so wet and flooded around here that I couldn't trailer her into the vet.
I didn't have any honey to hand, but did have some Underwoods left, so I started with that, hosed the wound thoroughly to start with, even though you don't have to with Underwoods, and have treated her twice a day from then.
I don't know how her healing is compared to not doing anything, or using a different product, but so far I'm happy with the progress.
At one week, it looked gunky so I hosed it again, not as reccomended, but I felt it needed it, only the second washing it got.
At two weeks from injury it was looking a lot better, apart from some straw stuck in it, but I left it alone.
Today 3 weeks from the original injury, looking pretty good.
I have never dealt with a cut like this before, so can't say if the Underwoods is a magic potion, but I am really please with the progress.