Real-Time Ultrasonography and Diagnosis of Pseudopregnancy in Swine
North Carolina State University Swine Reproduction Research from 2001. The effectiveness of using real-time ultrasonography for diagnosis of pseudopregnant sows was evaluated using 2000 sows on a commercial swine operation in N.C. Sows that were diagnosed as pregnant on day 28 of gestation were randomly assigned to receive either no further evaluation for pregnancy status (control, n=1000) or examination with a 5.0-MHz linear probe between days 65 and 75 of gestation (n=1000). More sows presumed to be pregnant at day 28 failed to farrow in the control treatment (132/905) than in the real-time ultrasound treatment (23/898). Nine of the 23 sows misdiagnosed with real-time ultrasound had fewer than 4 viable fetuses. These results demonstrate that real-time ultrasonography can be used as a management tool to effectively identify pseudopregnant sows.