Roles of animals within households across the world

Domestic animals are associated with multiple sociocultural and religious beliefs in societies around the world^{(Reference Alders, Campbell and Costa1)}. Their value is often deeply rooted in communities that have raised livestock for hundreds to thousands of years. In the Hindu religion, for instance, the cow is considered a sacred symbol of life to be protected and revered, as are sheep in the Chiapas Region of Mexico.

Scanes^{(Reference Scanes, Scanes and Toukhsati4)} reported that livestock can enhance human mental, physical, and spiritual health and well-being in a wide variety of ways. The services provided by animals to human health include the production of antivenom, therapeutic hormones, and xenografts^{(Reference Alders, Campbell and Costa1)}.

In resource-limited settings, livestock serve as essential components of livelihoods for small-scale producers. Their contributions include providing manure for use as dry dung fuel and organic fertilizer, as well as hauling power^{(Reference Alders, Campbell and Costa1)}. Livestock production and aquaculture provide employment for millions worldwide, particularly in low- and middle-income countries^{(Reference Grace, Bett and Cook5)}. The sector supports small-scale farmers and producers, pastoralists and workers involved with processing and distribution.

Livestock raised under extensive conditions are also critical to the provision of ecosystem services. As key components of many agroecosystems, they support circular food systems^{(Reference Alders, Campbell and Costa1,6)} . When regenerative management principles are applied, livestock production can contribute to soil health, biodiversity and climate change mitigation and adaptation^{(Reference Alders, Wingett, McFarlane, Butler and Higgs7,Reference Ramsden and Alders8)} . These animals contribute to the food supply by converting low-value materials—inedible or unpalatable for humans—into milk, meat, and eggs. This conversion reduces competition with people for food resources, particularly cereal grains and legumes^{(Reference Smith, Sones and Grace9)}.

Animals, along with their care and conservation, play a key role in achieving the Sustainable Development Goals (SDGs)^{(Reference Alders, Campbell and Costa1,10,11)} . Livestock, especially small livestock, contribute to empowering women and youth. However, it is also important to acknowledge that the integration of animal welfare and conservation into the SDGs remains limited^{(Reference Allgood12,Reference Keeling, Tunón and Olmos Antillón13)} . This gap should be more fully addressed in the post-2030 Agenda through a One Health and One Welfare lens. One Health is ‘an integrated, unifying approach that aims to sustainably balance and optimize the health of people, animals, and ecosystems’^{(Reference Adisasmito and Almuhairi14)}. One Welfare is an approach that highlights ‘the interconnections between animal welfare, human wellbeing and the environment’⁽¹⁵⁾. It is an approach that fosters interdisciplinary collaboration to improve human and animal welfare and also helps to promote key global objectives such as supporting food and nutrition security, sustainability, reducing human suffering and improving productivity within the agricultural sector through a better understanding of the value of high animal welfare standards.

Benefits of animal-source food to human diets

When managed sustainably, ASF can play a crucial role in human nutrition, economic development and environmental sustainability^{(Reference Beal, Gardner and Herrero16)}. These foods (including meat, offal, milk, eggs and fish) provide essential nutrients, contribute to food security and support livelihoods globally^{(Reference Beal, Manohar and Miachon17,Reference Wingett and Alders18)} . While their consumption varies across different socio-economic contexts, ASF remain a key component of balanced human diets^{(Reference Beal, Manohar and Miachon17,Reference Alders, Dumas and Rukambile19–Reference Sheffield, Fiorotto and Davis21)} .

Animal-source foods provide complete proteins, containing all essential amino acids for the growth and maintenance of muscles and organs, immune function and overall health⁽⁶⁾. Unlike plant-based proteins, ASF proteins are generally highly digestible and nutritionally superior to plant proteins, with higher amino acid bioavailability, making them especially beneficial for vulnerable populations such as children, women of reproductive age and the elderly^{(Reference Beal, Manohar and Miachon17,Reference Ajomiwe, Boland and Phongthai22)} . Unfortunately, many national dietary guidelines and food composition tables do not include mention of indigenous foods, locally produced ASF and offal, products that often have good nutrient profiles^{(Reference de Bruyn, Ferguson and Allmann-Farinelli23)} and are frequently more affordable^{(Reference Chan, Wong and Alders24)}.

Animal-source foods are rich in essential micronutrients often lacking in plant-based diets, such as:

• • Vitamin B₁₂ – almost exclusively found in meat, offal, dairy and eggs, B₁₂ is essential for brain function and red blood cell formation⁽²⁵⁾;

• • Iron – haem iron from meat and offal is more easily absorbed than non-haem iron from plant sources and is crucial to preventing anaemia^{(Reference Grace, Bett and Cook5)};

• • n-3 fatty acids – found in fish and some meats and offal, these fats are vital to heart and brain health⁽⁶⁾; and

• • Calcium and Vitamin D – essential for bone health, these nutrients are abundant in dairy products^{(Reference Alders, Campbell and Costa1)} and calcium is also available in eggshells^{(Reference Bartter, Diffey and Yeung26)}.

In rainfed agricultural systems, contributions to food security and resilience by ASF are considerable. Unlike seasonal crops, ASF can be consumed or stored to ensure a year-round protein and micronutrient supply⁽⁶⁾. Meat drying, fermentation and preservation techniques, help to bridge food supply gaps between crop and horticulture harvest seasons^{(Reference Ramsden and Alders8)}. Traditional preservation methods that do not require electricity, such as oiling or water glassing whole eggs for long-term storage^{(Reference Ahlers, Alders and Bagnol27)}, sundried fish and smoked meats, are widely used in many rainfed regions. In terms of building resilience in rainfed agricultural regions, ASF help to diversity food sources by integrating livestock with crop farming, ensuring more stable food systems by reducing reliance on seasonal plant harvests⁽⁶⁾. Livestock and poultry offer financial security as they can be sold or bartered during times of food scarcity^{(Reference Grace, Bett and Cook5,Reference Wong, de Bruyn and Bagnol28)} .

The amount and type of ASF that are both healthy and environmentally sustainable depend on local contexts and health priorities. These factors can shift over time as populations develop, nutritional needs evolve, and new, more acceptable alternative food technologies become available^{(Reference Beal, Gardner and Herrero16)}. Government and civil society efforts to modify ASF consumption—whether increasing or decreasing—should be guided by local nutritional and environmental conditions, and must involve consultation with stakeholders who may be affected by such changes. To support this, inclusive and context-specific policies, programs, and incentives are essential. These should promote best practices in ASF production, reduce excessive consumption where it is high, and sustainably increase it where intake remains low.

Benefits of nose-to-tail eating

Nose-to-tail eating is a sustainable and traditional approach to consuming ASF^{(Reference Nitzko and Spiller29)}. It emphasises the use of all edible parts rather than only selected cuts of meat and remains a common practice in most low- and middle-income countries. Historically practiced by many cultures, nose-to-tail eating is gaining renewed interest in high-income countries due to its environmental, nutritional and economic benefits. It is a practice that reduces food waste, supports ethical meat consumption, and provides a wide range of essential nutrients^{(Reference Wingett, Allman-Farinelli and Alders30)}.

One of the primary environmental advantages of nose-to-tail eating is its role in minimising food waste. Industrial meat production, especially in high-income countries, often focuses on premium cuts, discarding nutrient-dense organs, bones and offal. Utilising all edible components of animal carcases reduces landfill waste and ensures that more of the resources used in animal production – such as water, feed and energy – are fully utilised⁽⁶⁾.

By consuming all edible parts of an animal, the demand for additional livestock production is reduced, which in turn lowers greenhouse gas emissions^{(Reference Wingett, Allman-Farinelli and Alders30)}. Studies indicate that a more efficient use of ASF could significantly reduce the carbon footprint of ASF consumption^{(Reference Ramsden and Alders8)}. Additionally, using offal and bone for broths, sausages and other food products helps to optimise resource utilisation in the food industry.

Organ meats such as liver, heart and kidneys are rich in vitamins and minerals that are often lacking in muscle meat. For example, liver is an excellent source of vitamin A, iron and B vitamins, which are essential for immune function and energy production^{(Reference Spiegel and Wynn31)}. Bone marrow and connective tissues provide collagen, which supports joint and skin health⁽²⁵⁾. In addition, including a variety of offal in the diet ensures a more balanced intake of essential amino acids and micronutrients. This is particularly beneficial for populations with limited access to diverse food sources, as it maximises the nutritional value derived from each animal^{(Reference Grace, Bett and Cook5)}.

In terms of cost-efficiency, offal and other less consumed ASF are often more affordable than premium cuts, making nose-to-tail eating an economical choice for consumers. This approach provides access to high-quality protein at lower costs, which can be especially beneficial in low-income households and communities⁽⁶⁾.

An important ethical issue is ensuring that all edible components of an animal carcase are consumed to honour the sacrifice made for food. Indigenous and traditional cultures have long practiced nose-to-tail eating as a way of showing respect for nature and reducing waste^{(Reference Ramsden and Alders8)}.

Nose-to-tail eating offers numerous benefits, including reduced food waste, lower environmental impact, enhanced nutrition, cost efficiency and ethical ASF consumption. As the world seeks more sustainable food practices, adopting this approach can play a crucial role in improving food security and promoting responsible eating habits. Future efforts should focus on increasing awareness, culinary education and policy support to encourage broader adoption of nose-to-tail consumption, especially in high-income countries.