EFFECTS OF SHORT-TERM WHOLE-BODY VIBRATION ON ANIMALS WITH PARTICULAR REFERENCE TO POULTRY

Animals are exposed to various vibration and movement stimuli during transport. The vibrations are a potential source of stress in birds because the resonances they set up in the internal organs are likely to be major aversive stimuli. This paper considers the possible effects of vibration on broilers in transport by reference to the known effects of vibration on other species. The fundamental frequency of poultry transporters is between 1 and 2 Hz, with a secondary peak of 10 Hz and a chassis vibration in the lateral axis of 12-18 Hz. Suggested resonance frequencies for the viscera of broiler chickens exposed to vertical vibration are around 10 Hz, and so coincide with the secondary peak. Skeletal muscle responds to movement and vibration in order to maintain postural stability and reduce the effects of resonance. Standing birds maintain stability by wing extension and by flapping or squatting. Involuntary muscle and cardiac muscle are also affected by vibration with blood circulation, heart beat and possibly gut control changing as a result. Vibration-induced vasodilatation may occur, as may blood pooling in the organs, pulmonary damage and impaired thermoregulation. Biochemical changes resulting from vibration could have adverse effects on meat quality in birds unable to recover before slaughter.