Method for continuous measurement of blood metabolite hepatic balance in conscious preruminant calves.

A method of continuous in vivo flow measurement of plasma metabolites through the liver in calves was described. Five 2-wk old male calves were fitted with chronic catheters in the hepatic and portal veins and in the hepatic artery and with electromagnetic blood flow probes in the portal vein and in the hepatic artery. The reliability of measurements was tested during a 3-wk period in which calves were fed milk diets that curdled or did not curdle (uncurdled) in the abomasum. In comparison with a conventional curdled milk diet, the intake of uncurdled milk diet did not modify mean portal vein (47 to 49 ml.mn-1.kg live weight-1) or hepatic arterial (5.6 to 5.7 ml.mn-1.kg live weight-1) blood flows but did influence nycthemeral variations in portal blood flow rates, especially during the second part of the night.