Gestational Aging and Determination of Parturition Date in the Bitch and Queen Using Ultrasonography and Radiography.

This article provides a complete understanding of how radiography and ultrasound imaging can be used to determine gestational age when inadequate breeding data are available. Formulas for calculation of gestational age using both fetal and extrafetal structures are presented. Ultrasonographic descriptions of organ development and their use in determining gestational age are discussed. This information may be used to monitor the health and development of the fetuses and may be useful when the need to plan an elective or emergency Cesarean section occurs. Ultrasound imaging to assess fetal stress, viability, placental health and to sex fetuses is also described.