The causes of prolapse of the vagina prior to calving are probably multiple but are related to relaxed, stretched or long pelvic ligaments, with or without pelvic pressure.
Causes include:
1. Hereditary or genetic factors (relaxed or long)
2. Elevated estrogen hormones (relaxed)
3. Previous parturitions (stretched)
4. Over-distention of abdomen (pelvic pressure)
5. Excess pelvic fat (pelvic pressure)
Vaginal prolapses are often repeatable. If the cow has a vaginal prolapse and then is bred again, there is an increased likelihood that she will prolapse during the next pregnancy. In addition, there seems to be genetic component to vaginal prolapses. Therefore, culling these cows and not keeping their offspring as replacements makes sense.
