Abstract
Six Jersey cows were implanted with 8 pairs of bipolar electrodes in the ileo-ceco-colic (ICC) area. Starting at day 11 after surgery, myoelectric activity was recorded at 2- to 3-day intervals, three times for 8 hours or four times for 6 hours. A computer-based oscillograph and data acquisition program was used to record myoelectric activity of the ileum, cecum, and proximal loop of the ascending colon (PLAC). Data analysis was performed by visual examination and by use of a spike-counting program. Two types (A and B) of cyclic activity were found in the cecum and PLAC. While the cyclic activity type A occurred most frequently in the cecum, type B exclusively occurred in the PLAC. Phase III of the MMC in the ileum was accompanied by a hyperactivity type A at the level of the ICC junction in 60.90 + 12.65% (mean + SD) of the cases. Twenty-seven different types of orally and aborally propagated spike sequences, involving both the cecum and PLAC, were found. They occurred most frequently when an MMC-phase III was observed in the ileum, and least frequently when an MMC-phase I was observed in the ileum. All electrode sites of the cecum and PLAC served as pacemaker areas. Both propagated and non-propagated spikes were found at all electrode sites of the cecum and PLAC. Although propagated spikes lasted signficantly longer than nonpropagated spikes, no distinction based on duration could be defined between the two spike types because broad overlapping of duration existed. Ceco-colic spike frequency was significantly higher during MMC-phase III in the ileum than during MMC-phase I, and the duration of spike activity (expressed as percentage of time) was significantly higher during MMC-phases II and III in the ileum than during MMC phase I. It can be concluded that myoelectric activity of the cecum is well coordinated with the ileum and the PLAC. Phases of reduced, moderate, and increased myoelectric activity in the cecum and PLAC occur simultaneously with the phases I - III of the MMC in the ileum. The ICC area can be considered as a functional entity.
Steiner, Adrian (1993). Myoelectric activity of the cecum and proximal loop of the ascending colon in the cow. Master's thesis, Texas A&M University. Available electronically from
https : / /hdl .handle .net /1969 .1 /ETD -TAMU -1993 -THESIS -S882.