There are many different kinds of exams and procedures that owners may elect to do, it just depends on what they are trying to find out. There are physical exams, ultrasounds / palpations,cervical examinations, uterine cultures, uterine cytology, and a uterine biopsy. These exams can be used to see the conditions of a mare's uterus to determine the best course of action, and figure out if the mare is a candidate for breeding.
These exams can be very significant to know more about a mare's reproduction. They can help determine if she is not getting pregnant or keeping the pregnancy - Why?