Sometimes when you see something suddenly in a pattern of facts, things snap into focus. I've been mulling over the odd timing of Pie's nightly colic pain and gas after eating and trying to figure out why it happens then and what might be causing it. It's clear that there's some underlying condition - stones in the bile duct or the small intestine, or an infection/inflammation caused by something - encysted small strongyles or tapeworms (he's been treated for both and his recent fecal test was negative but those might not have shown up), bacteria or even the protozoa that cause EPM. But something aggravates the condition every evening, about 30 minutes to an hour after he eats dinner, and the timing and the specific elevated liver enzymes clearly indicate a problem with the bile ducts/small intestine. The underlying condition is not stomach ulcers - he doesn't present like a horse with ulcers - no unhappiness at feeding time or refusal to eat pellets - in fact he's an eager eater. It isn't likely to be sand colic - there's no diarrhea and his weight is good and he's eating eagerly. It isn't an impaction in the large colon - his manure if anything is a little loose after being on the antibiotics, and is profuse.
So what could it be? Nothing has changed in his diet, but if his sensitivity to whatever it is has increased, as a result of a change in the underlying condition perhaps triggered by his vaccinations a week ago, there's some component of his evening feed that's causing him extra distress. (He's not 100% normal the rest of the time, but about 90% OK until after evening feeding, when his condition becomes very uncomfortable very fast, and then usually improves again just as rapidly after a period of extreme discomfort.)
So I reviewed what goes into his evening feed - mineral/vitamin balancer pellets, magnesium/chromium powder, U-Gard and cocosoya oil. But wait! Bile is produced specifically to digest fats, and its production is increased as fats are presented to the digestive system. It could be the oil . . .
Tonight we're trying a test - we're giving him only his pellets, his Uniprim antibiotics and a little water to hold it together. We'll see what happens . . .
And our vet/chiro was out to look at him. She didn't do a full adjustment - until we get at whatever is making him feel punky, any adjustment she does won't stick, but she did some little things to make him feel better. She also did a neurological exam - I love that our chiro is a vet as she's useful for this stuff and very well informed. Pie has a couple of neurological oddities - one test is to pick the horse's foot up and put in in an odd position to the side and see if the horse corrects it - horses that are normal neurologically do this on their own. Pie was good with the fronts - the test is to place them to the side away from the body - Pie said "no, they belong here" and moved them back to center. The test with the hinds is to place one hind leg across and behind the other - Pie moved his right hind back immediately but would leave the left hind in the odd position for quite a while without moving it. When turned in a tight circle, he also didn't move his left hind completely normally, wanting to rotate on it and not lift it and cross it over. He's also had two incidents - one today - where he's stepped on his left hind with his right hind, once on the heel and once on the inside of the pastern, while running around. This could mean that his kinesthetic sense of where his left hind is located isn't quite right. This could be his normal, related to some stifle issues, or it could be a sign of something going on (that might or might not be related to his digestive difficulties). We did a blood draw to rule out EPM - the definitive results from the new ELISA test, which is inexpensive, should be back in a few days.
Pie has also developed a couple of sarcoid-like spots - one on his right barrel and one on his neck - that could also be an immune system response to the vaccinations - sometimes when a horse's immune system is challenged, either by illness or vaccination, other things that have been brewing and that the horse has been able to manage until then pop up and become symptomatic. I'll keep an eye on those spots - for now they're not a problem.
Our regular vet is coming back tomorrow to do a blood draw to recheck his liver enzyme levels - we want to be sure things aren't moving in the wrong direction and I want to discuss whether it makes sense to refer him to a vet clinic, where we could do a liver and spleen ultrasound and also a liver biopsy if that were warranted - we've got a couple of good clinics within two hours of us.
Keeping fingers crossed that we'll figure this out and get it under control, and we'll see if removing the fats from his dinner helps him be more comfortable.
Update at almost 2 hours after feeding time - so far Pie is feeling fine, no colic, no symptoms of any pain! Hoping this is a good sign, or that at least we've figured out how to keep him more comfortable while we're figuring out what the underlying problem is.