Recommended Animal Handling Guidelines and Audit Guide

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Recommended Animal Handling Guidelines and Audit Guide 2007 Edition(0.80 amp) would induce seizure activity and insensibility in small pigs. One disadvantage isthat the pigs regained sensibility more quickly compared to stunning at 50 to 60 cycles. Thepigs in this experiment weighed one-third less than comparable U.S. market pigs and thisprobably explains why the lower amperages were effective.Equipment is commercially available for stunning pigs at 800 hz applied across the head by twoelectrodes and a second stun with 50 to 60 hz from head to body. Research has shown that 800hz is effective when applied by two electrodes across the head.Research has shown that stunning pigs with frequencies higher than 50 to 60 cycles is effective.In this experiment, the pigs were stunned with a head only applicator. High frequency stunninghas never been verified to induce instant insensibility when applied as a single stun with a headto body electrode. This is the type of electrode used in many large U.S. pork slaughter plants.Vocalization As an Indicator of StressVocalizations immediately prior to stunning, such as squeals in pigs, and moos and bellows incattle and pigs, can be signs of discomfort and stress. To prevent vocalizations the electrodesmust be in firm contact with the animal prior to being energized.Squealing of pigs during electric stunning can be more frequent in plants that have return to sensibilityproblems. Research conducted in commercial pork slaughter plants where squealing wasmeasured with a sound meter indicated that the intensity of pigs squealing in the stunning chutearea is correlated with physiological measures of stress and poorer meat quality determined thatthe intensity of pig squeals is correlated with discomfort.Due to natural vocalization behavior, vocalization scoring is not recommended for sheep.Ensuring Insensibility Following Electric StunningAdequate electrical parameters for cardiac arrest stunning cannot be determined by clinical signs,because cardiac arrest masks the clinical signs of a seizure. Measurement of brain function isrequired to verify any new electrical parameters that may be used in the future. Common causesof a return to sensibility after electric stunning are:1) Wrong position of the electrode2) Amperage that is too low3) Poor bleed out, or4) Poor electrode contact with the animalOther factors that may contribute to poor electrical stunning are: dirty electrodes, insufficient wetness,electrode contact area that is too small, animal dehydration, dirty animals and long hair orwool. Interrupted contact during the stun may also be a problem. For all species, processing plantswith an excessively long stunning to bleed time are more likely to have return tosensibility problems.30AMIHandlingSlaughterGuidelines07.1AMIJune 11, 2007
Recommended Animal Handling Guidelines and Audit Guide 2007 EditionElectrodes must be cleaned frequently to ensure a good electrical connection. The minimumcleaning schedule should be once a day. For personal safety, the electrode wand must be disconnectedfrom the power supply before cleaning.Electric Cattle StunningUnlike pigs and sheep, electrical stunning of cattle may require a two-phase stun. Due to the largesize of cattle, a current should first be applied across the head to render the animal insensiblebefore a second current is applied from the head to the body to induce cardiac arrest. Modern systemsmay have a third current to reduce convulsions . A single 400 volt, 1.5 amp current passedfrom the neck to the brisket failed to induce epileptic form changes in the brain. Observations inplants outside the U.S. indicate that a single current passed from the middle of the forehead tothe body appears to be effective. Research is needed to verify this. To insure that the electrodesremain in firm contact with the bovine’s head for the duration of the stun, the animal’s head mustbe restrained in a mechanical apparatus. Due to the high electrical resistance of cattle hair, theelectrode should be equipped with a water system to provide continuous wetting during the stun.The Council of Europe (1991) requires a minimum of 2.5 amps applied across the head to induceimmediate epileptiform activity in the electro-encephalogram (EEG) of large cattle. A frequencyof 60 or 50 cycles should be used unless higher frequencies are verified in cattle by either electricalor neurotransmitter measurements taken from the brain. A more recent study has shownthat 1.15 amps sinusoidal AC 50 Hz applied for one second across a bovine’s head is effective toinduce insensibility (Wotton et al., 2000). A longer application is usually required to depolarizethe spine to reduce kicking (up to 15 seconds).CO 2StunningAccording to CFR 9, Section 313.5, CO 2stunning may be used in swine to induce death or toresult in a state of surgical anesthesia. These states are dependent on the relationship betweenexposure time and CO 2concentration, and systems will produce pigs in both states.Handlers must be careful not to overload the gondolas (elevator boxes) that hold groups of pigs.In a properly loaded gondola, the pigs must have sufficient room to stand or lie down without beingon top of each other. Handlers must never overload the gondolas by forcing pigs to jump ontop of each other.CO 2Stunning ParametersIn the scientific literature, there are conflicting results on how pigs react to the induction of CO 2anesthesia. One researcher found that purebred Yorkshire pigs have a calm induction and thatconvulsions and excitation occur after the pig becomes unconscious. Some genetic types of pigsactively attempt to escape from the container when they first sniff the gas and others respondwith a calm anesthetic induction. Other research has observed that the reaction of pigs to CO 2was highly variable. A Dutch researcher found that the excitation phase occurred prior to theonset of unconsciousness. Australian researchers found that being shocked with an electric prod31AMIHandlingSlaughterGuidelines07.1AMIJune 11, 2007
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Recommended Animal Handling Guidelines and Audit Guide

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