Effect of feed intake on digesta flow and myoelectric activity in the gastrointestinal tract of the preruminant calf.

The effect of feed intake on abomasal digesta outflow and gastrointestinal motility of preruminant calves given whole milk was studied. Digesta collections were made from calves fitted with re-entrant duodenal cannulas. In other calves myoelectric activity was recorded from electrodes implanted on the abomasum and proximal small intestine, sometimes concurrently with recordings from an electromagnetic flow sensor on the duodenum. After a feed of 2-8 kg milk recurring patterns of intestinal myoelectric activity associated with fasting were temporarily interrupted by a period of continuous irregular spike activity; the duration of the post feeding activity increased with intake of milk. Patterns of abomasal digesta flow were characterized by alternating periods of rapid and slower flow with a frequency that corresponded to cyclic change in myoelectric activity of the small intestine. Hourly rates of abomasal emptying of digesta during a 6-h collection period were significantly greater (P less than 0.05) after giving feeds of 6-8 kg milk compared with measurements of flow rate when 2 kg feeds were given. It is concluded that myoelectric activity of the proximal small intestine exercises control over abomasal emptying of digesta by a mechanism which adjusts the mixing and propulsive functions of gut motility in accordance with the amount of milk consumed.