There are several reasons of uterus prolaps by ewe.
Traumatic (caught up in a rush while feed distribution)
Obstetrical (early contractions)
For ewe, the uterus prolaps is before the lambing. The ewespoon, must be placed after cleaning and placing the genital tractus in its original place. Use always disposable gloves, and obstetrical gel. to keep the ewespoon in place, fix it to the wool, or fix a cord of the ewespoon to the ewe straps. The ewespoon must be released while lambing. Follow carefully ewe carrying an ewespoon to avoid any lambing problems.