The myoelectric activity of the cecum and right ventral colon (RVC) was studied in 4 female ponies. Eight, bipolar Ag-AgCl electrodes were sequentially placed on the seromuscular layer of the cecum (6 electrodes) and RVC (2 electrodes), and recordings were begun 14 days after surgery. The myoelectric activity for each pony was recorded during 12, 60-minute recording sessions done during the interdigestive period (3 to 7 hours after the morning feeding). Coordinated series of spike bursts were recognized as independent motility patterns in the cecum and in the RVC. Local haustra-haustra myoelectric activity involving approximately 40 cm of the cecal body (0.45 +/- 0.03 spike bursts/min) were detected. A series of spike bursts started at the cecal apex and progressed to, but stopped at, the caudal cecal base (0.40 +/- 0.03 spike bursts/min). Infrequently, a series of spike bursts started at the apex and progressed to the cranial cecal base (0.09 +/- 0.01 spike bursts/min). More commonly, a series of spike bursts with a conduction velocity of 3.8 +/- 0.07 cm/s, began in the cranial base and progressed orally to the cecal apex (0.46 +/- 0.03 spike bursts/min). Spike bursts conducted aborally (propulsion) beginning at the origin of the RVC (0.05 +/- 0.007 spike bursts/min) and spike bursts conducted orally (retropulsion; 0.15 +/- 0.02 spike bursts/min) were seen independent of cecal myoelectric activity. A progressive series of coordinated spike bursts, which began at the cecal apex, were conducted through the cecolic orifice and continued into the RVC (0.42 +/- 0.02 spike bursts/min), representing the only pattern common to the cecum and RVC.(ABSTRACT TRUNCATED AT 250 WORDS)