Abattoir Practices and Animal Products Technology

DESIDERATA NECESSARY FOR THE PRODUCTION OF GENUINE ANAESTHESIA

 The following desiderata are necessary for the production of genuine anaesthesia: The strength of the electric shock should be of sufficient magnitude; the strength of the current should not be less than 250 milliamperes, and the voltage should not be less than 75 volts.

• This strength ensures that the animal is killed outright by cardiac arrest or remains insensible until death occurs by exsanguination. The time recommended for a genuine electroplectic shock should be not less than 10 seconds.
• Every electric stunning apparatus should be fixed with indicators, which provide a warning if the current drops due to fluctuation in mains voltage or the time of application falls short of 10 seconds. The position of placing the electrodes so that the current will pass through the thalamus and cortex, the chief sensory centres in the fore-brain.
• The electrical resistance of the hair and skin may be lowered by ensuring that the electrodes are kept moist by immersion in brine and the skin of the head clean but dry.
• Passage of current is facilitated if the calorific intake of the animal is reduced and its state of hydration increased.
• The animal should be bled immediately after unconsciousness has been produced, otherwise it may regain consciousness though still remain paralysed.
• The failure of operators to observe these criteria has been the cause of criticism of electrical stunning methods.
• Firstly the method was not considered as humane and secondly haemorrhages were often observed in the muscular tissue of animals stunned by electrical means.
• The production of a genuine electroplectic shock and unconsciousness may be assumed if after application of the current the hind legs are stretched out violently, the fore legs are stiff, the head is bent back and respiration has ceased.
• In the absence of these manifestations it may be assumed that the animal has not been effectively stunned.
• The production of haemorrhages in the muscular tissue and lungs of animals stunned by electrical means has been unduly emphasised.
• These can be obviated or reduced considerably by prior resting, correct stunning and immediate bleeding.
• Keeping the electrical apparatus in position on the head and maintaining vaso-constriction until the moment the throat is cut, muscle haemorrhages can be reduced.