Parameters for stun-killing

If abattoirs wish to induce a stun-kill in as close as possible to 100% of birds, Table 5 suggests parameters, based on scientific research. At high frequencies (above 100 Hz), and/or if using certain modified waveforms, it is unlikely that the majority of birds will undergo cardiac arrest. Therefore low frequencies must be used. As well as choosing the correct frequency, the current amplitude must also be appropriate for inducing CVF. Usually, increasing the proportion of birds that experience a stun-kill requires an increase in the current amplitude, to a value beyond that necessary for effective [but recoverable] electronarcosis. For example, at 50 Hz sine AC, 105 mA RMS and 148 mA RMS may produce CVF in approximately 90% and 99% of broiler chickens, respectively.

Within a given set of electrical parameters, the incidence of CVF may vary between species, types, sexes and even batches of birds. For example, compared to lighter-weight turkeys (ie females), heavy, male turkeys may be less susceptible to CVF because their greater mass of skeletal (breast) muscle may reduce the amount of current that can reach the heart.

Table 5. Electrical parameters that may induce CVF in approximately 100% of birds. An application time of at least 10 seconds is likely to be suitable. The current amplitudes required for waterbath stunning by EC Regulation 1099/2009, induced CVF in 100% of turkeys and quail, when applied at 50 Hz sine AC.

Next: Monitoring stunning parameters