A TECHNIQUE FOR THE VENOUS CANNULATION OF THE MAMMARY-GLAND IN THE LACTATING SOW

The objective of this study was to develop a technique to cannulate th e mammary venous system of the lactating sow in conjunction with the c arotid artery. A total of 16 sows were subjected to surgery between d 3 and 6 of lactation. The dams were separated from their litter during the full surgical procedure and the post-surgical recovery period. Th e carotid artery was cannulated according to a previously described me thod. The mammary vein cannulation immediately followed the carotid ar tery cannulation. A small venous branch (approximately 4 mm in diamete r) located on the lateral side of the thoracic region was used to obta in access tp the mammary vein. It was isolated 4 to 5 cm above the pli ca lateralis, between the first and second anterior gland. The venous branch was exposed and a cannula inserted slowly for a distance of 16 cm or until the tip of the cannula would reach the most cranial point of the mammary vein. The cannula was allowed to follow the normal path of blood flow, running in a caudal to cranial direction. After recove ry from surgery (1 to 2 h), the dams were returned to their respective litters and treated with antibiotics for a minimum of 6 d. All sows n ursed and weaned normal litters. Cannulas were flushed with heparinize d saline (20 U/mL) every 8 h and both arterial and venous blood sample s (10 mt) were collected simultaneously at 0700, 1500, and 2300. Arter ial and venous cannulas remained patent for a minimum of 15 d. The loc ation of the cannula in the mammary vein was confirmed by postmortem e xamination.