Gastric cannulation of pregnant sows.

The purpose of this project was to study the effect of superalimentation in lactating sows through permanent, surgically placed, gastric cannulas. A surgical technique was developed to install gastric cannulas into pregnant sows to allow superalimentation by introducing feed through the cannula. After induction of general anesthesia, a flexible, T-shaped cannula (22 mm outside diameter) was surgically placed in the dorsal portion of the greater curvature of the stomach and exteriorized through the tenth intercostal space approximately 30 cm left of the dorsal midline. Cannulas were installed on day 85 +/- 5 days of gestation. Anesthesia, surgical procedures, and the subsequent presence of the cannula did not affect the size or number of live pigs at birth. In addition, the prevalence of stillbirths and mummified fetuses was not significantly different than that of noncannulated sows. The gastric cannulas did not affect lactation performance, as litter size and weight were unaffected when compared with that in noncannulated controls. Postmortem examination of euthanatized sows revealed adhesions of the gastric wall to the abdominal wall, thus eliminating the possibility of leakage of the gastric contents into the peritoneum. Detrimental effects of the cannulas on gastric function or capacity were not detected, and cannulas could be maintained through multiple parities.