So I’m the panicky type. And I have a horse that is about to make me explode out of my mind (some days, other days she’s perfect). So I get where the paranoia comes from. I have also been privileged to manage a private farm with a young gelding that was pretty sure he was in training to be a stunt man. So I know when to hold off on calling a vet as well.
I tend to try and assess causation with any injury. The big (more common) red flags for me are: non-weight bearing lame, swollen shut eye(s), unusual laying down (rolling, thrashing, groaning, etc), bleeding that won’t stop, if it needs stitches, excessive swelling, and high fever.
Horses are going to run around and twist their fetlocks/knees/hocks/etc in the field every now and then and there will often be some minor swelling and a minimal lameness from it. Some pain meds and some rest and the horse should improve quickly, if it gets worse or there is no change in 72 hours I call the vet.
Eyes are bad, eyes always need a vet, there is no reason (when dealing with an injury to the actual eye) NOT to call the vet. I’ve seen some horses injure their lids superficially without injury to the eye but if you suspect an eye injury, CALL THE VET. Oh and if you have to do eye meds, CATH THE EYE (it makes life easier).
Colic is a tricky thing. If you aren’t going to call the vet, I’d suggest only giving HALF a dose of banamine as a full dose of banamine can mask a surgical colic. If your horse is still in pain after half a dose, call the vet. I just call the vet.
Wounds are frustrating. Anything that penetrates the full thickness of the skin requires some attention. If it over a joint and there is some joint swelling, call the vet. Your horse can get a joint infection, go septic, do all sorts of nasty things even with a reasonably benign seeming cut. I like anything over an inch long that penetrates the full thickness of the skin to be stitched. If it’s in a highly mobile area, I might go as low as a 3/4 inch. Any cut that is accompanied by a fever requires vet attention as well. There is a window of time when stitching is an option and then you are out of it so, ideally, if you think your horse needs stitches you should text an image of the cleaned up injury to your vet. Also, any cut that doesn’t stop bleeding, horses can lose quite a bit of blood but you (ideally) want the vet there before the horses goes down from blood loss.
Excessive swelling may indicate many different problems including lymphangitis, cellulitis, allergic reaction, or internal injury. If it’s a wrap-able area I’ll usually wrap it until the vet gets there. It’s not going to magically go away between the time you call and the time the vet gets there.
High fever is the other reason to call a vet. Often times it is an indication of infection or disease but may be a symptom of something else such as a snake bite. In this instance, it might be pertinent to know things such as: is any other horse sick at the barn, does my horse have any open wounds, and is there any localized or systemic swelling?
Some other things to note would be: If he’s out all day and is in all night, he may be a little swollen come morning from standing in his stall all night. Vets usually don’t mind you texting them, just clear it with your vet first.