What is the liability if two partners strike their jointly-owned female slave, they both free her, and she subsequently miscarries a dead fetus?

Primary text

Based on the view of Abu Bakr, each partner owes the other partner half of one-tenth the value of the mother (half the Guwarrah). This is because each partner committed an injury against the fetus, and his own half of the fetus is extinguished from his liability. He is thus only liable for the half belonging to his partner, calculated based on the value of the mother at the time of the injurious act.