Today the topic is horse urine - that's right, horse urine. The reason for the topic is that Red had an odd little episode late last week. I'd groomed and ridden him as usual in the afternoon. In the early evening I came back to ride Pie - a group of us often get together on Thursday evenings. I discovered Red in his stall, swishing his tail, kicking at his belly and with urine dribbling out of his sheath. He wasn't dropped. I took him out and used some warm water and gauze to clean things out a bit - he was fairly dirty and once he figured out I was going to be gentle and that I was making things better, he stopped trying to cow kick. He seemed more comfortable after that, and the problem didn't reoccur.
But I usually have the boys cleaned (those of you with gelding know what I mean) twice a year - Pie in particular tends to get very dirty and also gets lots of beans. I usually do this at the time of spring and fall vaccinations, but my appointment for Pie's rabies shot this fall was a quick add-on to someone else's appointment and I didn't think about sheath cleaning.
So the vet came out this week to clean up the boys. Both had to be sedated. Pie was pretty good. Red was less cooperative and had to have extra medicine so he wouldn't kick. Red only had one small bean and wasn't too dirty; Pie as usual really needed to be cleaned, and had several fairly large beans. But the vet said that Red's problem was probably due to a crystal in his urine getting slightly stuck or irritating things as it passed - not a full-sized kidney stone (horses do get these too on occasion), but just due to the composition of horse urine. Apparently horses have crystals in their urine - who knew?
Here's some information:
Urine is a complex and supersaturated solution of many substances, including mineral salts that might precipitate out of solution into crystals under certain conditions; kidney/bladder stones are formed by combination of many small crystals into a larger conglomerate. Variation in the mineral content of feeds and water can influence the formation of stones. In some instances, a change in the acid-base relationship (pH) in the thick "soup" of urine can also trigger formation of stones. If you have ever seen your horse pass urine, you likely have recognized a couple of differences from the urine voided by dogs (or by yourself). First, horse urine is very cloudy. Cloudiness is a consequence of the large amount of calcium carbonate crystals that horses normally excrete in urine. While humans and dogs tend to regulate calcium absorption from the diet at the level of the intestine, horses tend to absorb excessive amounts of calcium from the intestine and must eliminate it via urine. If urine is collected in a transparent container and allowed to sit for a few minutes, these calcium carbonate crystals will actually settle to the bottom of the container--imagine one of those travel souvenirs that you shake to disperse "snowflakes" throughout the water, only to have them settle at the base of the Empire State Building. Second, horse urine is very bubbly (almost foamy) when it is first passed. This is due to the large amount of mucus in horse urine. In fact, a concentrated urine sample can be quite stringy and viscid (thick). Mucus is secreted from the innermost portion of the kidney (the renal pelvis), which is the start of the drainage system through the ureter. Mucus acts as a lubricant that can help prevent small calcium carbonate crystals from forming into stones. (thehorse.com article on urinary tract problems)All seems well with Red for now, which is a good thing. If he'd had a true stone, he'd have shown more pain signs, possibly blood in his urine and likely have been trying to urinate without being able to produce much.
Maybe more than you wanted to know, but interesting none the less (at least to me).