It is obligatory for him to have a female offspring of one year; because the loss is first allocated to the exemption, and if the loss does not exceed the exemption, the obligation remains as it is. If the loss exceeds the exemption, the loss is allocated to the threshold that follows the exemption, as in the case where fifteen out of forty camels perish; the four are allocated to the exemption, then eleven are allocated to the threshold that follows the exemption, which is between twenty-five and thirty, until a female offspring of one year becomes obligatory. See: Sharh Al-Wiqayah by Ibn Malik, p. 54/A-B, and Radd Al-Muhtar 2: 21.