It can detect the status of pre-ovulatory follicles, and help your veterinarian accurately predict the onset of ovulation even if the mare shows none of the classic behavioral signs. Zajac points out that rectal palpation is still an important adjunct for the detection of ovulation. Just before ovulation, there's a softening, and it feels mushy. That's something you can only tell by palpating. Fertility Problems Revealed Yet another avenue in which ultrasound has proven invaluable is in the diagnosis of infertility problems in mares.
Uterine cysts are one common occurrence, especially in older mares.
The cysts make it difficult for a conceived embryo to attach itself to the uterine wall. Present before breeding, these cysts usually are fluid-filled and thus show up black on an ultrasound scan. They can be in practically any position in the uterus. Sometimes they're innocuous and don't interfere with a pregnancy, but sometimes they do. What's particularly tricky about uterine cysts is that they might masquerade as a pregnancy.