Technical note: ruminal vein catheterization and continuous blood flow measurement in ruminal arteries of sheep.

Eight wethers were used to test the technique. Silicone rubber catheters were introduced into both ruminal veins so that their tips lay a few centimeters from the splenic vein. Arterial blood flow to the rumen was measured by an ultrasonic transit-time flow meter with 3-mm probes implanted around the left and right ruminal arteries. No loss of patency of the venous catheters was observed before slaughter (2 to 6 mo after surgery). There was no evidence of extensive vascular trauma due to catheterization at postmortem examination. In vivo calibration of the flow probes showed that reliable measurements could be made until at least 6 mo after implantation. With an accurate method of blood flow measurement in ruminal arteries and guaranteed long-term catheter patency, it would be possible to make reliable estimates of nutrient uptake across the ruminal wall of sheep over an experimental period of several months.