Head-Only Stunning of Turkeys Part 2: Subjective and Objective Assessment of the Application of AC and DC Waveforms.

Electrical stunning is likely to remain an important stunning method for turkeys at slaughter. The purpose of this study is to understand the application of various waveforms of alternating current (AC) and pulsed direct currents (DC), head-only, to turkeys and to improve the effectiveness of handheld stunning of turkeys. We evaluated the effectiveness of stunning by documenting physical responses and recording electroencephalograms (EEGs). For the assessment of physical responses, the stunning voltage was varied depending on the proportion of animals effectively stunned at a certain voltage level. If all turkeys in a group of 10 were stunned, the voltage was decreased, and the next group was stunned. This was repeated until not all turkeys showed signs of being effectively stunned. The experiment was then repeated at the voltage level just above the one that showed incomplete effective stunning. The effects of the stunning on the EEG recording was assessed in 16 turkeys to measure the occurrence of epileptiform EEGs, in 14 turkeys to assess epileptiform EEGs after neck-cut (bleeding), and in 14 turkeys to assess the effect of increased voltage and reduced frequency on epileptiform EEGs. Assessing EEGs in a laboratory setting contributes considerably to the understanding of electrical stunning procedures. Voltages between 125 and 250 V, depending on the waveform assessed, were effective in producing an effective stun in turkeys in this study.

Head-Only Stunning of Turkeys Part 1: The Minimum Voltage Necessary to Break Down the Inherent High Resistance.

Pre-slaughter stunning is required for humane slaughter. For turkeys, head-only electrical stunning is most often used by small scale producers. To ensure immediate and effective stunning, the impedance (resistance) of the tissue of the head of the animal situated between the two electrodes needs to be overcome swiftly. The impedance is a function of the voltage and decreases non-linearly with increasing voltage. In this paper, we describe a method to assess the minimum voltage needed at which the impedance no longer decreases, that is likely to produce an effective stun. For ethical reasons, gas stunned, electrically naïve turkeys were used to measure impedance at various levels of voltage and current. Several combinations of voltage and frequency, alternate current (AC), direct current (DC) and pulsed DC, were identified that would be sufficient to achieve the maximum decrease in the impedance, and therefore would allow the highest current and the most effective stun. A minimum, expressed as Root Mean Squared voltage, of 150 V and 50 Hz. would be required in AC, 175 V in pulsed DC at 30% cycle (150 at 50% cycle), and 225 V if voltage spikes of very short duration were used. Sinusoidal AC applied at 150 V, 50 Hz was selected for further testing.

Assessing cattle welfare at slaughter - Why is it important and what challenges are faced?

The welfare of animals in the meat industry, especially at the time of slaughter, has become an area of increasing public scrutiny and has prompted research on its assessment, and enhancement. Fundamental factors such as the effects of transport, reactions of the animals to novel environments and underlying commercial pressures which impose 'speed' and 'robustness of action' in the way animals are handled, can pose a challenge when establishing a valid, reliable and feasible welfare assessment protocol for use at slaughter. The purpose of this review is to assess published work on animal welfare at slaughter, with a focus on the current methods used to assess cattle welfare in the slaughterhouse, which are outlined in the scientific and trade literature, and how these relate to the interaction between the environment, the animal, and slaughterhouse personnel.

The perception and acceptability of pre-slaughter and post-slaughter stunning for Halal production: The views of UK Islamic scholars and Halal consumers.

The importance of religious slaughter from economic, emotive and ethical viewpoints is significant. There are apparent economic benefits associated with trading in meats slaughtered according to religious traditions. Some religious authorities insist on the slaughter of animals without stunning, but this, according to many researchers, compromises animal welfare. We conducted a survey of Islamic scholars and Halal consumers, 66 scholars from 55 organisations and 314 consumers from 54 UK cities/towns were surveyed. Forty-nine scholars were interviewed through pre-arranged meetings, 17 surveyed online whilst all 314 consumers were either surveyed online or through the remote completion of copies of the questionnaire. Most of the scholars (>95%) (CI 86.9 to 98.4%) agreed that if an animal is stunned and then slaughtered by a Muslim and the method of stunning does not result in death, cause physical injury or obstruct bleed-out, the meat would be Halal and 53% (CI 47 to 58%) consumers also thought such meat would be Halal.

Halal stunning and slaughter: Criteria for the assessment of dead animals.

The debate surrounding the acceptability of stunning for Halal slaughter is one that is likely to linger. Compared to a couple of decades or so ago, one may argue that pre-slaughter stunning is becoming a popular practice during Halal slaughter due to the increasing number of Muslim-majority countries who continue to issue religious rulings (Fatwa) to approve the practice. Concerns have often, however been raised about the likelihood of some animals dying as a result of stunning and whether there are mechanisms in place to identify and remove dead animals stunned with irreversible techniques before their necks are cut. This paper reviews literature about what makes meat Halal, considers the arguments put forward by proponents and opponents of pre-slaughter stunning for Halal production and examines the criteria used by Halal Certification Bodies to identify and reject animals that may die as a result of irreversible stunning and considers the specific risks of waterbath stunning (for poultry) from a Halal viewpoint.

A comparison of blood loss during the Halal slaughter of lambs following Traditional Religious Slaughter without stunning, Electric Head-Only Stunning and Post-Cut Electric Head-Only Stunning.

Blood lost at exsanguination during the Halal slaughter of lambs was compared between the slaughter methods of Traditional Religious Slaughter without stunning (TRS), Electric Head-Only Stunning (EHOS) and Post-Cut Electric Head-Only Stunning (PCEHOS). Two protocols were examined, Experimental (80 lambs) and Commercial (360 lambs), assessing varying periods of animal orientation during the 4 min bleeding process (upright orientation before vertical hanging). Live-weight, blood weight (Experimental only), carcass weights and by-product weights were recorded. The Experimental protocol highlighted an increase in blood loss at 60s in EHOS and PCEHOS compared to TRS (P<0.001) but by 90 s there was no significant difference. A post-slaughter change in animal orientation from an upright to a vertical hanging position aided the amount of blood loss. The bleeding of lambs is largely completed by 2 min. There were no significant differences (P>0.05) in final blood loss between treatments. This research was undertaken to inform discussion on the merits of different slaughter methods compatible with Halal requirements.

Stunning and slaughter of ostriches.

A study of the commercial stunning and slaughter of 783 ostriches in a Republic of South African abattoir revealed that a simple ostrich handling system, combined with a leg clamp applied during stunning current flow and operated by experienced ostrich slaughtermen, resulted in a humane, efficient slaughter process. It was estimated that an electrical stunning current in excess of 400 milliamps at 50 Hz AC, applied to the head only, would prevent recovery in more than 90% of the ostriches, when bled within 60 s from the start of stunning. The identification of rhythmic breathing movements indicate the first stages of recovery and is therefore an essential diagnostic 'tool' in recognising the effectiveness of the stunning treatment. The identification of rhythmic breathing movements in the ostrich after stunning is difficult because spinal reflexes, which produce contraction of limb muscles and result in almost rhythmic body movements could easily be confused with breathing movements.