Research at the University of Illinois shows the value of using real-time ultrasound (RTU) to monitor and assess the reproductive status of sows and gilts.

Researchers Rob Knox and Gary Althouse, DVM, report that the ability to look inside the animal, nonsurgically, gives breeding herd managers and veterinarians a powerful management and diagnostic tool for improving and troubleshooting breeding herd performance.

As research continues on RTU, one of the early benefits has been early pregnancy diagnosis. According to the Illinois researchers, differences between pregnant and non-pregnant females can be visualized as early as day 17 and day 18 after mating and becomes very prominent by days 19 to 20.

The early detection with RTU may allow greater precision in determining pregnancy status than external monitoring procedures. Identifying open sows at that early stage allows for rapid rebreeding and fewer non-productive sow days.

The researchers used RTU to investigate the variation in ovulation after detection of estrus in sow groups weaned at different times of the year, in response to length of lactation, parity and interval from weaning to estrus.

Data collected shows that the greatest number of sows (55%) ovulate from 36 to 48 hours after onset estrus. Approximately 20% of sows ovulate before and another 20% of sows ovulate after the 36- to 48-hour period.

Knox and Althouse also note that the RTU is useful for diagnosing pathologic conditions in sows. For example, cystic ovaries and uterine infections can readily be diagnosed, therefore aiding the veterinarian and producer in treatment, mating or culling decisions.

The University of Illinois Departments of Animal Science and Veterinary Medicine and the Illinois State University Department of Agriculture collaborated on the RTU project. Researchers developed techniques to perform transrectal imaging in standard gestation crates quickly and without stress or strain on the sow.

The technique involves the attachment of the ultrasound probe to a transrectal stabilizing rod. Once inserted into the rectum, the probe allows visualizati on of the reproductive tract.

The technology is based on B-mode ultrasound, which emits and collects ultrasonic waves via a transducer. The waves echo off tissues, with differences between tissues displayed on a monitor in a continuous scale from black to white. The resulting image of the reproductive structures are then interpreted for reproductive status.

The researchers evaluated both portable units and medical grade imaging devices. They found differences between the units in their ability to provide adequate resolution for imaging the ovaries clearly. Knox and Althouse suggest that if monitoring of ovarian activity is desired, the equipment must provide the necessary resolution for differentiating ovarian structures (i.e., follicles, corpora lutea and inactive ovaries).

Researchers: Rob Knox and Gary Althouse, University of Illinois. Phone Knox at (217) 244-5177 or e-mail rknox@uiuc.edu. Phone Althouse at (217) 333-8116.