Evaluations with your veterinarian should include the following. A complete assessment of the mares physical condition and her prior breeding history. A complete reproductive tract evaluation usually will yield some valuable information. I usually perform all of these with the exception of the vaginoscope exam unless adhesions are anticipated. Later, if the mare does get in foal, then evaluation of Estrone Sulfate and Progesterone levels helps in maintaining a pregnancy as older mares sometimes have hormonal abnormalities.
Results often suggest treatments which are usually beneficial.
Uterine cysts, uterine fibrosis, chronic low grade endometritis, or ovarian inactivity are some of the common reasons given for a poor prognosis to an owner. Even if your older mare does get in foal and survives EED, there are still some increased risks latter in gestation which include rupturing the middle uterine artery which usually results in death, vaginal vein rupture is less severe but can cause hemorrhage problems, premature placental separation, and increasing the severity of existing musculoskeletal problems. The ultimate goal of every breeder is one live foal per mare per year. Older mares certainly can achieve this goal, but owners must realize that the prognosis for fertility ,conception and delivery decreases on a yearly basis. The cost of trying to achieve that goal with older mares can get way out of line in a hurry and a proper evaluation at the right time can not only save many headaches but it can also correct many reproductive problems before you start, giving the mare a much better chance of success.