Whilst food security is of increasing global concern, so too are issues of food waste. It is estimated that up to a quarter of food brought into the home is subsequently discarded uneaten [1
], representing a significant waste of environmental and economic resources [2
]. When meat is wasted, this represents a concomitant waste of animal life. Approximately 16% of Australian household food waste is animal meat [3
Food waste occurs across the food supply chain, from “paddock to plate”. This is mirrored to some extent in the domestic sphere, where food waste can occur at key stages related to the purchase, preparation, consumption and disposal of products intended for human consumption [5
Councils, waste collectors and recyclers routinely collect data on the quantity and composition of household waste, including household organics. However, these metrics are limited to formal waste disposal streams. A number of informal waste disposal streams are also used in households. Reynolds and colleagues detailed and estimated five informal food waste disposal streams used in Australian households: home composting, sewer disposal, giving to charity, dumping or incineration, and feeding scraps to pets [6
]. Together, these streams represented 20% of Australian household food waste flows [7
]. The amount of food waste redirected to pet alimentation by the average Australian household was estimated at 200 grams per week. If sent to landfill, this additional food waste would generate approximately 60,000 tonnes of greenhouse gasses every year [8
The redirection of food intended for human consumption to pet alimentation has occurred since humans began domesticating animals around 10,000 years ago [9
]. As a supplement to their main food sources, scraps have been fed to animals to support their production of meat, eggs, milk, wool and transport for human benefit [10
]. In post-medieval Britain for example, “almost every family kept a sty pig that was fattened on household scraps and then recycled as ham, pork, bacon and dripping” [9
]. However, not all human societies fed animals their food scraps as a deliberate act. In some cases, humans simply tolerated animals that have taken advantage of excess human food. For instance, Egyptian artwork depicts cats poised under chairs, often eating from bowls or feeding on scraps [11
]. However, cats really started making themselves at home around human settlements during the rise of agriculture. Darwin [12
] noted 200 years ago that domestic cats have longer intestines than wildcats, a trait he attributed to them as an adaption to being fed on kitchen scraps.
Indigenous Australians maintained populations of dingoes (and later dogs) for companionship, security, hunting assistants (in select cases), play objects, and for spiritual purposes [13
]. These dogs were occasionally given food intended for humans, but this was usually when there was excess (note, the ability to store food was limited), and typically reserved for the dogs considered “favourites”. These canids provided the added benefit of acting as campsite cleaners, with both dingoes and dogs constantly scavenging around camp for food scraps and human faeces (that contain potentially harmful pathogens). Some consider this scavenging behaviour to have been essential in maintaining a sanitary and clean site, extending the period that humans could remain in a specific location [14
]. Although domestic animals can benefit from being fed (arguably more consistently than they would in the wild), in the majority of the scenarios presented here, food and food scraps given to animals were always low in quality, and competition amongst the animals high [9
]. In the case of Indigenous Australian cultures for instance, dogs were often in poor physical condition [13
], and there was a never-ending battle for food [18
There are potential benefits of re-routing food waste from landfill to pet food, especially relevant at a commercial level in relation primarily to the economic benefits of producing additional products with “waste” and/or negating the costs of waste disposal. However, the risk of zoonoses is significant, with examples such as bovine spongiform encephalopathy [19
]. The BSE epidemic in the UK was caused by the feeding of recycled and processed waste products of cattle, some of which were infected with BSE, to other cattle [20
]. The difficulties in responding to BSE involved the complex interrelationships between animal feed and cattle production, slaughter and meat processing, together with the rendering of inedible offal and international trade in animal products [19
]. A UK ban on feeding ruminant protein to ruminants in 1988 resulted in a delayed decline in new cases by 1992, due to the long incubation period of the disease [20
]. It is also illegal in most countries to feed food waste to pigs due to the risk of disease transmission; for example, pig industry experts in Australia considered the risk of spread of infectious diseases from south-east Asia to be mostly related to disposal of food waste [21
]. In a review, Sapkota et al.
] discussed the risks due to presence of bacteria, antibiotic-resistant bacteria, prions, arsenicals, and dioxins in feed and animal-based food products, and concluded there are insufficient surveillance systems to monitor these risks [22
Benefits and risks also apply to the practice of feeding scraps to pets in domestic spheres. Environmental benefits may arise from redirecting food scraps from landfill to pets, especially when the feeding of scraps leads to a concomitant reduction in the purchase of other feed. At the same time, there may be risks of obesity, toxicity or other poor animal health outcomes [22
In general, the pathway from “paddock to pet” or “paddock to plate-licker” takes two forms according to the intention of the ingredients at point of preparation. The most widely accepted is the billion-dollar pet food industry based on ingredients originally intended for pet consumption and subject to rigorous market research. The other form is food originally intended for human consumption. Whilst the former is considered preferential for pets, the latter could be preferential for the environment. However, little research has considered the implications of the redirection of food waste to pet alimentation. This paper considers the social, veterinary and environmental implications of feeding food to animals that was originally intended for human consumption. These complex issues are explored empirically in relation to dogs.
Food Waste and Dogs
Over one third of Australian households own a dog [24
]. As omnivores, dogs—more than cats—are the recipients of household scraps. Dogs and humans have shared their living spaces for thousands of years, developing complex patterns of biological and behavioural interactions. The grey wolf that was the progenitor of the domesticated dog probably began to live close to human settlements in order to scavenge for food [25
]. Today’s domestic dog relies almost entirely on humans for food. The first commercial dog food was a dog biscuit, produced and sold in 1860 [26
]. In 2009, Australian dog owners were estimated to spend over 1.1 billion dollars on pet food and increasing, consistent with increases in both the US and the UK [24
], and mirroring the movement of dogs into our hearts, houses, and families. We involve dogs in all basic human activities. We sleep with them [27
], we eat with them, and sometimes we cook for them [28
Dog owners have basically two options for feeding: a homemade diet, commercial food or a combination. Commercial pet foods may be dry, wet or semi-moist [29
]. To cater to a wide range of customers (where customers are dogs as well as their owners), a variety of commercial foods have been developed, using natural and organic foods, raw food diets and vegetarian products. Commercially prepared foods compared with homemade foods offer convenience, consistency, reasonable assurance of quality and nutritional balance, plus potential cost savings [30
]. In the US and Australia, non-commercial foods, which included table scraps, are fed to 30% of dogs [31
]. Practices may differ between working or rural dogs and household pets. For example, a study of working farm dogs in New Zealand found the most common diet fed was a combination of dry food and “home kill”, which was fed by 328/542 (61%) of owners during peak and 313/542 (58%) during off-peak periods of work [32
While it was estimated in 2004 in the US that most dogs received 90% of their nutrition or more from commercial foods [30
], confidence in commercial pet foods was shaken in 2007 when widespread contamination with melamine in commercial pet foods in the US led to many deaths due to acute renal failure [33
]. In an exposé of how this crisis was mishandled, Nestle highlights how many different pet labels from cheap to expensive brands were all produced in the same factory, a fact most consumers would have been unaware of if not for the need to recall the affected brands [33
]. This may have resulted in more dog owners using homemade diets, although data on the feeding practices of dog owners is lacking. Stockman and Kass [34
] reviewed two hundred recipes for homemade diet from 34 sources, and concluded that few contained all of the essential nutrients at sufficient concentrations [34
]. While raw food diets have become increasingly popular and there is a growing number of pet food cook books [35
], the lack of evidence and consensus on what is best to feed dogs makes it difficult even for veterinarians to make informed feeding recommendations to owners [36
As well as providing dogs with the nutritional requirements to grow and remain healthy, feeding practices also express different kinds of relationship with a co-habiting species. This is reinforced by sociological studies that have determined that human feeding practices are symbolic of relations of reciprocity, care and love [37
]. However, kindness can kill and in some cases, humans are responsible for obesity in dogs. In Australia, the prevalence of overweight and obesity in dogs is estimated at 41% [39
]. Obesity is associated with a persistent low-grade inflammation and increased oxidative stress, which is thought to have a role in chronic diseases such as osteoarthritis, cardiovascular disease, and diabetes mellitus [40
]. Generally, obesity is associated with increased morbidity, and early mortality [41
]. Many owners of overweight companion animals treat their pet more like a human than as an typical companion animal, and as such have a strong bond with their pet [23
]. Owners who share a strong bond may be less likely to perceive their pet as overweight or obese [42
]. Indeed, one study found that owners who fed more table scraps had overweight dogs [43
]. Regardless of body condition, 59% of dogs received table scraps, which constituted 21% of daily caloric intake. The nutrient density of scraps fed was variable and did not meet the National Research Council’s recommendations for micronutrient adequacy. Feeding high fat table scraps to dogs may also put them at risk of pancreatitis, with a study of risk factors for canine pancreatitis in the United States reporting dogs that ingested table scraps the week before diagnosis (OR, 2.2) or throughout life (OR, 2.2) had increased odds of having pancreatitis [44
While there is some information relating to the feeding of table scraps to dogs, there is little understanding of the proportion of owners feeding food waste to their pets, their demographics, their decision-making processes, household composition, and the types of dogs more likely to be fed food scraps. In particular, there has been no investigation into any relationship between practices of feeding scraps to pets and the animals’ body condition, living arrangements (inside or outside) and exercise regimes. However, this information is essential to the success of environmental or public health campaigns designed to optimise the practice of feeding food waste to pets.
This paper reports on two studies. The first marketing study reports pet feeding practices from a wider food waste research project, establishing some early findings for the feeding of food waste to dogs and pets more generally. The second veterinary study focuses explicitly on dog owners and addresses the role of table scraps in dog feeding and to the dog’s heath. Together, the two studies synthesise information that enables a consideration of the environmental considerations of feeding food scraps to pets.
In the absence of research on the topic of feeding food to pets that was originally intended for human consumption, namely food scraps, the aim of this paper was to understand what proportion of owners fed scraps to their dogs, their demographics, decision-making, household composition, and types of dogs. We also sought to determine relationships between practices of feeding scraps to pets and the animals’ body condition, living arrangements (inside or outside) and animal exercise regime.
Overall, most respondents did not feed table scraps and, where they did, the amounts did not constitute much of the total food discards of that household. The tendency to refrain from feeding scraps was associated with a tendency to monitor dogs’ weight. People who fed scraps did not generally include them as part of their dog’s main meal.
People feeding scraps as part of main meals were more likely to be in larger households. It is likely that larger households (especially those with children) produce sufficient quantities of scraps throughout the day to be aggregated into a pet meal. Females and those who owned medium sized dogs were also more likely to engage in feeding table scraps to pets. Moreover, larger households may make it difficult to monitor food given to dogs.
Although these factors require further investigation with a larger sample, they suggest that females and owners of medium sized dogs might benefit from veterinary information about “safe” and “healthy” pet feeding practices. The same information would worth including in information for owners abut more environmentally sustainable pet feeding practices.
The surveys reported in this paper indicate Australian pet owner practices of feeding food waste and table scraps as pet alimentation. However, they rely on subjective measures of household food waste and the dogs’ body condition. Moreover, the dog-focused survey did not elicit data on how many meals the dog received in a typical day. Such data is required to reveal correlations between people and practices that could in turn inform the development of successful sustainable pet feeding interventions.
Of particular limitation, the survey tools reported here used key terms uncritically. Research on the psychological and socio-cultural determinants of household food waste has highlighted various assumptions around the meanings of terms such as “food waste” or “scraps” [5
]. There is often incongruity between householders’ definitions of food waste and researchers’ calculations. Peelings or other items considered (culturally) “inedible” are often discounted by the former but included by the latter, despite the environmental impact being relatively equal. There is often confusion about the inclusion of liquids in the category of food waste or whether it is restricted to solids, complicated by a natural process of liquidation that occurs to organic solids such as food products.
Avenues for food waste disposal vary between councils, regions, states and countries. These may be accompanied by cultural, social and geographic differences in relation to feeding practices and animal ownership. For example, dog owners in remote Australian Indigenous communities have little access to commercial food. In some central European countries such as Slovakia, scraps are the main source of food for dogs [48
]. Furthermore, the processes of domestic food purchase, preparation and housework (which would include clearing away dirty dishes and scraps) is traditionally considered “women’s work”. Further research should consider these important structural, geographic, social and cultural differences in pet feeding practices and the role of food waste.
Whilst the research on humans consuming animals spans both the social and natural sciences, research on humans feeding animals is largely relegated to issues of animal nutrition, health and safety. However, there is a real need for the social sciences to engage in research on “feeding animals”. Following the aforementioned socio-cultural dimensions of human-to-human feeding practices, there remains a need to consider how human practices of feeding pets and other animals symbolise, perform or create relations; which kinds of relations and for what purposes. These relational dimensions of human practices of feeding animals could be accessed by social scientists using animal attachment scales as well as more qualitative methodologies. In situ
ethnographic research would bolster such findings by triangulating stated and revealed behaviours [52
It is not only domestic pets that help humans dispose of food. Whilst the data presented in this paper relates to small animals most likely to share human domestic spaces, large companion animals like alpacas, llamas, goats, pigs, camels and horses also warrant attention in relation to their potential role in food waste disposal. Larger animals also can be fed on the leftovers or offcuts of food intended for human consumption, often substituting commercial stock feed [53
]. In industrialised countries, this usually occurs during times of drought when traditional feed is scarce. Nonetheless, there is a clear need to understand how human practices of feeding animals differ according to different kinds of animals. This includes differences along species lines, as well as differences in the social construction of different kinds of animals. For example, animals can be categorised as pets, companion animals, livestock, or wildlife. Domestic animals are bifurcated categorically into pets or livestock; the former kept primarily for love and the latter for money. Whether an animal is kept primarily for love, lifestyle or livelihood may impact the owner/guardians’ willingness or reluctance to provide “food waste” to those animals.
These suggested categories are of course purely academic; livestock producers and horse owners frequently report feelings of love for their large animals, and some guardians of small animals would see them as having a utilitarian work function akin to that of many horses. However, there is a need to move beyond the pet/livestock binary to consider different types of relationship with different kinds, sizes and uses of animals, if not only for understanding what contributes to decisions about how and what they are fed. Whilst lifestock and livestock may not be an obvious diversion stream for food waste, understanding the social dimensions of how humans provide them with food will become increasingly important to the sustainable feeding of animals relying on broad-acre cropping and commercial grain production.
Overall, this paper is framed by the assumption that feeding food waste to pets is a more environmentally sustainable alternative to purchasing pre-packaged, commercial pet food. However, commercial pet food can be made from ingredients that would otherwise have been treated as waste products. It could also have produced waste, as might owners who prepare their own meals for pets. In saying this, however, we know little about the health implications of feeding table scraps to animals. For example, animal owners need more education on the calories of such food and whether they are feeding their animals too much, and what foods are harmful to dogs. There may be misunderstandings or differences in the perception of what foods are suitable for dogs. We therefore need to audit knowledge and beliefs. For example, should we be feeding dogs food that we consider unfit for human consumption, or should they only eat food suitable for human consumption? The time and place of feeding scraps also needs to be considered [54
]. For example, feeding scraps while preparing meals, or when eating at the dinner table might encourage undesirable behaviours such as begging (often resulting in increased intake of food), or dangerous behaviours such as aggression or “stealing” food from vulnerable infants or fragile elderly. Information could be distributed through pet adoption centres, registration bodies, puppy preschool classes, or local councils.
Finally, the greenhouse gas emissions potential of animal manure produced from eating scraps of food originally intended for humans is thought to be lower than that of rotting food scraps [55
]. An environmental accounting perspective is required to provide a broad systems understanding of these issues. Part of this requires a supply chain approach to understand the ramifications of feeding food waste to pets across the whole food chain. Whilst feeding food waste to pets may reduce the amount of food going to landfill, there may be little impact on food waste related to purchasing and storage. Answering the questions identified throughout this paper will require mixed methodologies and multi-disciplinary collaborations involving experts such as social scientists, environmental mathematicians, nutritionists, veterinarians, behaviour change experts and animal owners and carers themselves. Whilst companion animals sustain the psychological, social and cultural wellbeing of almost two thirds of households in developed countries, research is required to make sure that sustaining pets is itself a sustainable practice.