Gastric electromyographic activity in the milk-fed lamb

Area of Science:

• Veterinary Physiology
• Ruminant Digestion
• Electromyography

Background:

• The reticulum, reticulo-omasal orifice (ROO), and abomasum are key digestive organs in ruminants.
• Understanding their coordinated electromyographic (EMG) activity is essential for comprehending digestive processes in young animals.

Purpose of the Study:

• To investigate the electromyographic (EMG) activity patterns of the reticulum, reticulo-omasal orifice (ROO), and abomasum in conscious lambs.
• To correlate these EMG activities with physiological states such as fasting, milk anticipation, and sucking.

Main Methods:

• Electromyographic (EMG) recordings were obtained from the reticulum, ROO, and abomasum of conscious lambs.
• EMG activity was analyzed during fasting, in anticipation of milk, during sucking, and post-feeding.

Main Results:

• Fasted lambs exhibited regular reticular EMG bursts with associated ROO quiescence, followed by ROO activity.
• Milk anticipation led to prolonged ROO inactivity and altered reticular EMG patterns.
• Sucking induced ROO quiescence and monophasic reticular EMG bursts, with ROO inactivity persisting after atropine, phentolamine, or propranolol administration, but not hexamethonium.
• Post-feeding, ROO inactivity periods were shorter and short ROO bursts occurred more frequently compared to fasted lambs.

Conclusions:

• The reticulo-omasal orifice (ROO) demonstrates significant EMG activity modulation in response to feeding cues and the act of sucking in lambs.
• Nervous system control, potentially involving cholinergic and adrenergic pathways, influences ROO activity during feeding behaviors.
• These findings elucidate the complex neuromuscular control of the upper digestive tract in young ruminants.