The infection, as evidenced from pathogenic bacteria being grown from biopsies and culture swabs, is located some 16 to 20 inches into the mare's reproductive system from her vulva.
Most of these chronic infections are in old mares that pool urine and/or get fecal contamination from an old, worn out vulva. Traditionally, most of these old mares have either had several foals and/or have dropped in their backs from age and years of riding which has contributed to their uterus being located lower than their vulva and much lower than it was at one time.
Also, traditionally, most of these mares have been sent to a sale or a 'trader' that comes through and offers slaughter prices for them. At some point, their value hits a point where the money needed to keep them breeding or comfortable enough to continue riding hits a point where it is not worth what is costs to keep them either breedable or rideable. They are then sold or put down.
Now, as commercial breeders unload these older problem mares, individuals have stepped up and tried to 'rescue' them. So, many of the older mares with chronic uterine infections are absolutely miserable, get thinner and thinner, and live that way for years rather than being dumped on the market or put down. It is just as unfair to a good old mare to keep her around this way as it is to keep one around that is 3-legged lame. Same difference to me.
Anyone that owns one of these old miserable wrecks just needs to set a dollar amount and a point at which they give up trying to save one of these mares. If they insist on trying to keep one comfortable as long as they can, then they need to haul her to the nearest LARGE breeding farm with a GOOD resident reproduction Vet or to a Vet School that teaches advanced reproduction techniques to graduate students. These severe problems do not respond to back-yard home do-it-yourself techniques. If they can be corrected at all, you are looking at $1500.00 to $2500.00 at the very least and you still have an old mare and a temporary fix.
A chronically infected old mare is MISERABLE. That is why they get thin and keep going downhill.
This is not a very cheery post, but it is the hard reality and truth about older mares.