RUMINAL VEIN CATHETERIZATION AND CONTINUOUS BLOOD-FLOW MEASUREMENT INRUMINAL ARTERIES OF SHEEP

Eight wethers were used to test the technique. Silicone rubber cathete rs were introduced into both ruminal veins so that their tips lay a fe w 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 pate ncy of the venous catheters was observed before slaughter (2 to 6 mo a fter surgery). There was no evidence of extensive vascular trauma due to catheterization at postmortem examination. In vivo calibration of t he flow probes showed that reliable measurements could be made until a t least 6 mo after implantation. With an accurate method of blood flow measurement in ruminal arteries and guaranteed long-term catheter pat ency, it would be possible to make reliable estimates of nutrient upta ke across the ruminal wall of sheep over an experimental period of sev eral months.