Horse has stopped moving around in his pasture
As some of you may know, I own a horse "in absentium", I study abroad and while I'm away my stable owner takes care of him like her own. Yesterday I got a message saying he'd developed a large swelling in his sheath, she called the vet and he was there within 20 minutes, he gave two injections and a supplement to help him pee more. He didn't know WHY, but said it should go away over the weekend.
My stable owner attached in the message a worry that he's stopped moving around in his pasture, whether it's snowy, icy or bare. This has been going on for a while, she says. So it probably isn't related to his sheath issue.
He's a 13 year old STB off the track for a few years. He's barefoot. She's put studded boots on him now to see if he's just unsure of his footing, but I doubt that'll solve the problem.
He doesn't walk with any lameness (he's been lame several times so both I and my stable owner are experienced at seeing when it appears). But he'll go out into his pasture, and spend his day just standing by the hayrack while his buddy is all over the place.
This is not behaviour that is like my horse. He's always running around, looking for grass straws, investigating stuff. I've recently had a reminder that behavioural changes in horses should be taken seriously.
I'm pretty lost for ideas but I'm thinking ... could a possibility be back issues? I'm struggling to find the English word here but a common issue especially in ex-racehorses is that they get what we call "lockages" in their backs and/or necks. It's an issue equine chiropractors deal with, I'm really sorry I can't find the technical term for it but I'm sure some wiz on here will be able to recall the English word.
He was also vaccinated (and teeth floated) a few weeks ago, and I'm wondering whether he could be having a reaction to his vaccines? Unlikely, but I'm putting it out there.
I'd really appreciate some input on this, problem-solving from afar is a bit difficult but I'm doing what I can!