It's great to see so many people getting involved in this blog (I know that's a horrible word, but it's what we call a site like this). I just want to get all smug and self-satisfied about the fact that I've been doing it for years. I started my blog, pretentiously titled Investigations of a Dog, in 2006. It covers my research interests in horses and military history, and all kinds of other things, so there should be plenty to interest people here. In future I might cross-post horse stuff that would be relevant here, but for now you can explore my archives. In the sidebar of my site there's a cloud of keywords (eg horses, cavalry), and clicking on one of them will bring up all the posts tagged with that word.
Some things which people might find particularly useful:
My Social-Political Animals paper. Not just about horses, but suggests a more materialist approach to bringing the non-human into early-modern social history.
A whole series of posts on cavalry charges. Say no to equine battering rams!
Somewhere there are also some tentative thoughts on the gendering of war horses, although I've changed my mind about a lot of it since then. The points Erica raised about horse clothes might change things even more. It's probably about time I wrote something new on this to see where I've got to. I've been thinking about it for 3 years but I'm still not entirely sure what questions I should be asking, let alone how to answer them.