This research was composed of three experiments:Experiment1:Pregnancy diagnosis experience of Landrace as surrogate sows which generated cloned Wuzhishan minipigsIn this study, the real-time B-mode (brightness mode) ultrasonography associated with the early pregnancy diagnosis kit was used for pregnancy diagnosis in surrogate sows. The best time for early pregnancy diagnosis in cloned Wuzhishan minipigs was the30th day after embryo transfer, when the gestational sac and conceptus reflection can be detected; on the52th day after embryo transfer, the number of fetuses, fetal bones and head and spine can be detected. Also on the87th day the fetal movement could be detected. In addition, throughout the course of pregnancy, the use of real-time B-mode (brightness mode) ultrasonography associated with early pregnancy diagnosis kit for pregnancy diagnosis in surrogate sows, could timely eliminate interference and improve the diagnostic accuracy of pregnancy diagnosis in cloned Wuzhishan minipigs.Experiment2:Ultrasonographic assessment of embryonic and fetal development in cloned Wuzhishan minipigs’gestationThe goals of the present study were to describe the reference standard images of cloned Wuzhishan minipigs in the whole gestation with a3.5-5.0MHz transabdominal B mode ultrasonography and the relationship between evolution of the embryonic and fetal structures’ values and time of gestation.In early gestation, the earliest time to detect the conceptus reflex was25d after mating and then the fetal head and eye orbits first appeared on day40of gestation. From day45of gestation, besides the head and eye orbits, the fetal skeletons and spinal column were clear enough to be measured. In addition, the fetal heart, heartbeats and fetal movements were first detected on day50of gestation, from the date of which the fetal chest, abdomen and the related organs were also present on the B mode ultrasound images.From day18until day50of gestation, the gestational sac and conceptus variation curves for cloned Wuzhishan minipigs were calculated, the equation for relationship between the long axis of conceptus and the gestational age (y=0.2091x-3.815, R2=0.8043), and that for the circumference of conceptus (y=2.0323e00411x, R2=0.8847) had the higher coefficient of determination. However, gestational equations established for the long axis of gestational sac and the circumference of gestational sac as follow:y=0.1875x-0.9564, R2=0.6493and y=0.3942x+0.3829, R2=0.6996, had their low coefficient values. From day50until day108of gestation, the corresponding regression curves were also calculated. The best fitted curve equations were shown as follow:The long axis of the heart:y=0.0019x1.5009, R2=0.8598; Heart circumference:y=0.8254e00199x, R2=0.8257; The long axis of the head:y=1.6227e00117x, R2=0.7918; Head circumference:y=0.6875x06612, R2=0.7976; The long axis of the trunk:y=1.0042e00176x, R2=0.9492; Trunk circumference:y=2.9651e00175x, R2=0.9362; where x represented the gestational age. Results showed that the transabdominal B mode ultrasonography measurements of embryonic and fetal structures’values were useful methods for monitoring and estimating gestational age in cloned Wuzhishan minipigs. Experiment3:Fetal movements’variation of cloned Wuzhishan minipigs during late gestationIn this test, by means of transabdominal ultrasonography fetal movements of cloned Wuzhishan miniature pig during late gestation was studied, including%of fetal movements’ duration occurred within60min, the trend in occurrence over time and heart rate of sows and fetus. The results showed that, incidence and duration time of head movements(HM) was highest, forelimb movements (LM) followed by, general movements (GM) less (P<0.05), rotation(ROT)(P<0.01) occurred rarely. Except that ROT showed no particular trend over time, the occurrence of GM, HM, LM showed a significant decreasing trend towards parturition (P<0.05). Total fetal activity (the sum of the four fetal movements occurred) as gestation progressed, was significantly reduced (from27.23±2.01%to9.05±1.23%). In addition, as gestation progressed, the fetal heart rate gradually decreased, a significant negative correlation was observed between the fetal heart rate and the fetal age, the regression equation was y=-0.854x+213.12(x=Fetal age, y=Fetal heart rate, R2=0.7247), the heart rate of the sows in late gestation gradually increased with progressing gestation and the corresponding regression equation was y=1.596x-44.117(x=Fetal age, y=sows’ heart rate, R2=0.7247).