At least 200 billion black soldier fly (Hermetia illucens) larvae (BSFL) are reared each year as food and feed, and the insect farming industry is projected to grow rapidly. Despite interest by consumers, producers, and legislators, no empirical evidence exists to guide producers in practicing humane – or instantaneous – slaughter for these novel mini-livestock. BSFL may be slaughtered via freezing, boiling, grinding, or other methods; however standard operating procedures (SOPs) and equipment design may affect the likelihood of instantaneous death using these methods. We tested how larval body size and particle size plate hole diameter affect the likelihood of instantaneous death for black soldier fly larvae that are slaughtered using a standard meat grinder. Larval body size did not affect the likelihood of instantaneous death for larvae that are 106–175 mg in mass. However, particle size plate hole diameter had a significant effect on the likelihood of instantaneous death, with only 54% of larvae experiencing an instant death when using the largest particle size plate (12-mm hole diameter) compared to 84% using the smallest particle size plate (2.55 mm). However, a higher percentage of instantaneous death (up to 99%) could be achieved by reducing the proportion of larvae that become stuck in the machine. We conclude by outlining specific recommendations to support producers in achieving a 99% instantaneous death rate through specific SOPs to be used with similarly designed machines. We also develop a protocol for producers that wish to test their own grinding SOPs.

Over the last several decades an alternative to current methods of stunning cattle has been developed. This system, DTS: Diathermic Syncope®, has been suggested to the Jewish and Muslim communities as a means to achieve pre-cut stunning in conformity with both religious and EU regulations without a need to resort to a derogation that permits an exemption from the EU requirement to pre-stun all animals undergoing slaughter. The developer’s contention is that the system induces fainting, and thus should be acceptable to all groups, including the kosher (Jewish) and Halal (Muslim) consumer. A review of the system based on publications and reports from the developer itself suggests that in reality the system selectively heats the brain, leading to an epileptic-type seizure with tonic-clonic phases and unconsciousness lasting several minutes. It does not induce a (benign) faint, and use of the system might cause structural brain damage. Thus, this system is unlikely to be acceptable under Jewish religious law and its animal welfare value can be questioned.

Ethical principles guide decisions about what we consider to be right or wrong proposals and actions, so that when value judgements are made these engage us in ethics. Ethical thinking is clearly relevant to decisions about the way we treat animals, and such thinking has led to the commonly held view that animal use by people is acceptable provided that such use is humane. The ethical requirement that we treat animals humanely means that we must minimise the harms we do to all animals in our care or under our control. Accordingly, we must assess what harms are done to the animals, how bad each harm is in terms of its intensity and duration, what methods are available or can be developed to minimise each harm, and the relative effectiveness of those methods of harm minimisation. We must also seek to use the most humane methods currently available that can be practically applied. Ethically driven scientific evaluations of this sort have improved the humaneness of livestock slaughter and vertebrate pest control. For instance, detailed studies of different pre-slaughter stunning methods have validated their use to pre-empt the pain and distress that otherwise conscious animals would experience during the fatal neck cut and the short period of consciousness (sensibility) that follows it Likewise, reducing injuries caused by restraint traps has improved the humaneness of this vertebrate pest control method, and comparing the effects of different poisons has allowed the least humane ones to be identified. Difficult questions nevertheless remain at the problematic interface between quantitative scientific observations and their interpretation regarding the suffering that animals may experience, as well as questions about the relativities of different types of suffering.

The adoption of slaughter and pre-slaughter techniques to improve animal welfare and meat quality and safety is dependent on providing appropriate information, application and enforcement as well as information ownership by local people. The World Society for the Protection of Animals (WSPA) and Beijing Chaoyang Anhua Animal Product Safety Research Institute (APSRI) have been running a humane slaughter programme in China for more than three years. The aim of the programme is to improve the welfare of animals slaughtered in China through a three-pronged approach: i) train core-plant mid-level managers to be humane slaughter trainers; ii) provide guidance on legislation and codes of practice; and iii) develop and implement pre-slaughter and slaughter animal welfare curricula for undergraduate veterinarians. The production of in-country training material is based on a training-needs analysis conducted prior to the programme. Four Chinese trainers have completed the training and become national level trainers. In the last three years they have trained more than 5,000 staff from 800 slaughterhouses. Technical standards for slaughtering pigs, based on those of the OIE, have been adopted in China and the veterinary curriculum development is progressing. The programme has introduced many positive changes to the Chinese slaughter industry and the signs are positive for good progress.

The prevention of unnecessary suffering at slaughter is considered to be an imperative and, as such, the majority of animals slaughtered under industrial conditions are stunned prior to slaughter by mechanical, electrical or gas inhalation means. However, many Orthodox Jewish and Muslim communities do not accept pre-slaughter stunning. Those Jewish and Muslim communities that do accept pre-slaughter stunning require that any such stun is fully reversible in order to meet the requirements of their religious laws. Head-only electrical stunning is widely used in sheep, as it is a reversible method of stunning, but in cattle, the stun duration can be so short that the animal may regain consciousness during exsanguination. The concept of using electromagnetic radiation to induce insensibility has been proposed. Early attempts to induce insensibility and death in laboratory species were successful, but the technology to apply the technique to larger animals was not available at that time. More recently, however, technological advances have led to new work in the areas of transcranial magnetic stimulation and microwave irradiation, both of which are potential methods of inducing a recoverable stun in larger species.

Stunning prior to slaughter is commonly used to render the animal insensible to pain. However, for certain markets, stunning is disallowed, unless the animal can fully recover if not slaughtered. There are very few available methods of inducing a fully recoverable stun. This preliminary study investigates the potential for microwave energy application to be used to induce a recoverable stun in sheep. Cadaver heads were used to demonstrate that brain temperature could be raised to a point at which insensibility would be expected to occur (44°C). Trials on four anaesthetised sheep confirmed this finding in a live animal model where brain temperatures between 43 and 48°C were achieved with 20 s of microwave energy application. Although the applicator and process variables require some further development, this technology seems eminently suitable for use as an alternative method of inducing a recoverable stun.

Low atmospheric pressure stunning (LAPS) is a slaughter technique which may be less stressful for pigs (Sus scrofa domestica) than current commercial stunning and slaughter methods. The main methods used currently for slaughtering pigs are electric and carbon dioxide stunning, both of which are widely recognised as stressful for pigs. There is currently no published research on the use of LAPS for stunning adult pigs, however there is a significant body of relevant experience from investigations into the effects of low pressure and hypoxia on humans, hypoxia for killing pigs and the use of LAPS for killing poultry, rats and piglets. In this paper, the basic physics and biology of LAPS is briefly reviewed and relevant experience from research with humans, poultry, rats and piglets is presented. On the basis of this information, some initial parameters for LAPS trials with pigs are proposed, potential welfare issues identified and an approach to achieving LAPS at a commercially viable speed is outlined. While the effects of LAPS on pigs is, at present, uncertain, the evidence from research with humans and other animals suggests that healthy, fasted pigs undergoing LAPS are unlikely to suffer from air hunger or from pain. Any pigs suffering from upper respiratory tract disease, tooth decay or excess gas in the alimentary canal may, however, experience pain. A total killing cycle is likely to require 9 to 14 min. To implement LAPS in a commercial, high throughput processing plant will require the use of multiple decompression cylinders. The evidence available suggests that LAPS could be commercially viable for pig slaughter and that for most pigs it will be less stressful than current commercial slaughter methods.