Author: Sarah Babington

Can the slaughter of animals for meat production be humane?

The way in which an animal is slaughtered can have a major impact on their overall lifetime welfare. The point of slaughter is the last opportunity for an animal to be provided good welfare. While much of the research on animal welfare has focused on improving the welfare of animals during their lifetime, there is a growing interest in improving the way in which animals are slaughtered. 

The word humane is defined as showing kindness, care, and sympathy towards humans and animals. As it relates to slaughter, humane can be interpreted to mean killing an animal in a way that causes no or the least amount of pain, suffering, and distress as possible. There is an argument to be had that for something to be truly humane it should cause no harm to the welfare of an animal, which would mean slaughter cannot be humane because killing an animal by default causes harm (Browning & Veit, 2020). A similar argument could be made generally for commercial farming systems given that animals will inevitably be exposed to experiences that are both positive and negative throughout their lifetime on farm. Although this is an interesting philosophical argument worth considering, at present billions of animals are farmed and slaughtered globally so it is important that we strive towards providing them good welfare throughout their lifetime and slaughter them in a way that causes no pain, suffering, or distress.  

Are current slaughter methods humane?

When slaughtering animals commercially the system must balance animal welfare, environmental, and economic outcomes. There are numerous welfare risks associated with the way in which animals are currently slaughtered especially when conducted at mass in large commercial systems. The welfare risks posed to animals will depend on the system and the method of slaughter which can vary widely between countries.

At present in commercial systems animals likely experience some degree of stress prior to slaughter from factors such as transport, feed deprivation, new environment, mixing of unfamiliar animals, and handling. Electric prodders may be routinely used to move certain species (cattle, pigs, and sheep/goat) which can increase stress in animals and are often relied upon by staff in the absence of good handling practices (Grandin, 2020). 

Slaughter methods where animals are bled out without being stunned and rendered unconscious are arguably inhumane because animals likely experience pain, suffering, and distress from the neck cut and during the bleed out process before death (Tetlow et al., 2022). In many countries, like Australia, animals are legally required to be stunned before slaughter (some exceptions are made for cases of Kosher slaughter). Stunning is a procedure that causes an animal to lose consciousness immediately or in a way that does not cause pain, suffering, or distress, so that the animal is insensible while they are bled out and until death occurs (World Organisation for Animal Health, 2024). In commercial production systems the available stunning methods can be classified as mechanical, electrical, and gas stunning systems (Hewitt & Small, 2022). The choice of stunning system will be influenced by the species, production throughput, available infrastructure, cost, local manufacturers, and market access requirements. Each stunning system has advantages and disadvantages from a welfare and practicality standpoint making them more or less humane for animals (see Table 1 for summary). 

Table 1. Advantages and disadvantages associated with common stunning methods used for commercial slaughter of animals. 

From a welfare standpoint in many cases firearms may be the most humane method of slaughter because it allows for an animal to be killed in-situ with minimal restraint and causes immediate loss of consciousness and death when effective. Firearms may be feasible in small-scale systems such as mobile slaughtering units or on-farm slaughter where there is a very low throughput of animals. However, using firearms in large commercial systems that have a high throughput slaughtering hundreds to thousands of animals is not feasible due to the cost, time it takes, as well as operator safety concerns. The current stunning methods used in large commercial systems require that animals are either individually restrained which is stressful (e.g., mechanical and electrical stunning methods) or the method itself is aversive (e.g., carbon dioxide gas stunning). Overall, there are a number of animal welfare challenges facing the industry which means slaughter in these large commercial systems at present is in most cases not truly humane. 

Can slaughter methods ever be truly humane?

If slaughter in large commercial systems today is not humane, then it begs the question: can slaughter in these systems ever be truly humane? Although inherent stressors like transport and handling of animals may be unavoidable, it is reasonable to think that we could have a way of slaughtering animals at scale in the future that does not cause them pain, suffering, or distress. For slaughter to be as humane as possible, ideally animals would be farmed and slaughtered on-farm using a method such as a firearm with a head shot position that causes immediate unconsciousness and death. This version of humane slaughter as discussed above is likely not feasible when slaughtering large numbers of animals at scale. 

Some of the factors that impact whether humane slaughter is possible in large commercial systems include the people, handling methods, stunning and slaughter methods, animal welfare monitoring, and regulations. 

People

Improving animal welfare begins with people, which in the context of slaughter includes those directly handling the live animals as well as the consumers of the resulting meat products. For animal welfare to improve on-farm and at slaughter it will involve capital investment and may result in a higher cost of production. Consumer awareness and demand for meat products that are more humanely produced will play a critical role in incentivising and supporting producers and processors to improve animal welfare (Alonso et al., 2020). 

At slaughtering establishments there is a need to foster a workplace culture that prioritises animal welfare. It is important that staff that work with and handle live animals at slaughtering establishments have a good attitude and are competent with an understanding of animal behaviour (Grandin, 2013). Staff resourcing and production speeds should also be set at a rate to ensure that animals are not being pressured to move faster than normal and maintain a steady flow during processing. 

Handling

General best practice handling methods are essential if aiming to minimise the stress animals may experience before slaughter. Importantly animal temperament and prior experience of handling on-farm will influence how easy animals are to handle as well as their risk for stress during handling at slaughtering establishments. Animals should be habituated to people and being handled in similar environments to that of a slaughtering establishment if possible (e.g., being moved in and out of pens by person on foot or horse) so that they are easier to handle and less likely to be stressed before slaughter (Grandin, 2013). Additionally, best practice handling of animals relies on good infrastructure and design to support animals’ natural flow of movement (e.g., sheep will move in single file lines compared to pigs prefer to move in small groups side by side) at slaughtering establishments. The use of electric prodders for moving animals should be replaced with good practice handling methods and alternative handling aids because they cause avoidable stress and pain (Grandin, 2020). 

Stunning and slaughter technologies

There are a number of animal welfare challenges associated with all of the stunning methods that are currently used in commercial systems. Ideally a stunning method would require minimal restrain, be non-aversive, and cause unconsciousness without the animal experiencing pain, suffering, or distress. Ongoing research and developments in future technology could address some of the disadvantages of current stunning methods and provide more humane stunning alternatives. There has already been progress made for alternative stunning methods for poultry including low atmospheric pressure stunning and the use of inert gases (Gent et al., 2020). Similarly, for pigs there are several research projects in progress, such as the PigStun Project, that aim to identify and develop non-aversive commercial stunning methods for pigs. 

Animal welfare monitoring technologies

Monitoring animal welfare with a combination of animal-, resource- and management-based measures is important for the management and maintenance of good animal welfare during slaughter. Currently, most of the monitoring for animal welfare is completed by quality assurance staff or animal welfare officers at slaughtering establishments. External audits are also conducted periodically by regulators and retail customers to validate compliance. Animal welfare monitoring may be untaken in-person or remotely with advances in camera and video surveillance technologies (Buller et al., 2020). The recent introduction and use of artificial intelligent technologies to monitor animal welfare has the potential to optimise monitoring of animal welfare at slaughtering establishments. The large amounts of objective data that can be collected and analysed by artificial intelligent systems in real-time means trends and welfare issues could be identified early and addressed to improve both production and animal welfare. 

Regulations

Government regulations should set minimum standards for animal welfare at slaughter and be effectively implemented and enforced. It is also important that the industry demonstrates a degree of self-regulation to set a higher standard for animal welfare for themselves. Improvements in animal welfare should be driven by industry to show initiative and evidence of striving towards best practice. Additionally, industry should be able to provide evidence of good animal welfare outcomes at slaughter which will promote public trust, while being transparent about the continued welfare challenges and work being done to address them. 

Summary

The slaughter of animals by definition will always pose risks to the welfare of those animals being slaughtered. The current animal welfare challenges associated with commercial slaughter globally today means that in many cases it is not humane for animals. However, if these challenges were addressed with collaborative efforts, continued research, and advances in technology there is a future in which the commercial slaughter of animals could be humane.