Do Animals Get Depressed and what does this mean for animal agriculture?
- Grain Brain
- 3 minutes ago
- 7 min read
Can animals get depressed, or are we projecting?
Everyone has felt sad at some point in their lives, affected by circumstances that make them feel bad. Many people suffer from depression, whether triggered by circumstance or illness. These emotions are not limited to the human domain, as animals also experience a spectrum of feelings, from joy to sorrow.
One of the undiscussed facets of animal welfare is a difficult topic: animal depression. Once brushed aside as anthropomorphic speculation or emotional nonsense, emerging research has revealed the intricacies of animal emotions, prompting a deeper examination of its implications, particularly within the realm of animal agriculture.
Animal Behaviour
Anyone who has a loving relationship with an animal knows that animals can exhibit behaviours indicative of depression. Several studies have proven this scientifically through different models and contexts. For example, Albayrak and Erbaș (2021) review experimental models of depression in animals, highlighting how stress-induced models can mimic depression-like behaviours in animals (Albayrak & Erbaș, 2021). Another study by Aghajani et al. (2022) investigates how the antidepressant paroxetine impacts reproductive function in depressed and healthy animals, suggesting that depression affects reproductive health (Aghajani et al., 2022). Additionally, Wu et al. (2023) found a positive association between the intake of animal offal and depressive symptoms in humans, implying dietary influences on depression, particularly in those eating meat (Wu et al., 2023).
Another study by Hidayat et al. (2020) examines how chronic stress induces depressive behaviours in rats (Hidayat et al., 2020). The control rat group was housed relatively comfortably, while the experimental group were exposed to cold temperatures, small housing and forced into interactions with other rats that they did not know. The level of depression experienced by the rats was then measured with the forced swim test, a pretty pointless measure. They found that the stressed, or abused, rats swam for a significantly shorter length of time. But they also examined the brains of the rats, discovering reduced serotonin and increased brain cell death. Lastly, Chakma et al. (2021) compare depression levels between pet owners and non-pet owners, finding lower depression rates among pet owners, showing that the mental health of humans improves when they share their life with an animal (Chakma et al., 2021).
Paper Title | Insight |
Highlights various animal models of depression induced by stress, useful for understanding depression and testing treatments. | |
Shows that paroxetine can restore reproductive function in depressed animals, suggesting links between depression and reproductive health. | |
Demonstrates a positive association between animal offal intake and depressive symptoms in humans. | |
Examines how chronic stress induces depressive behaviours in rats, with neuronal cell apoptosis as a contributing factor. | |
Finds lower levels of depression among pet owners, suggesting the mental health benefits of pet ownership. |
What Does It Look Like?
Animals show depression through a persistent low mood. They may lose interest in food or activities, they can withdraw and have sleep disturbances, reduced motivation, and possibly self-harming or excessive grooming. It is important to note that animals cannot exhibit the behaviours that they would in nature during episodes of stress or depression due to being confined in farming situations. We should also keep in mind that it is the farming situation that is causing the depression.
Cows can show depression through decreased appetite, social withdrawal, reduced activity and lethargy. They will have altered vocalisations, and be distressed when separated from the herd, and will have a tendency to isolate themselves or lose interest in normally enjoyed activities, with environmental stress and lack of positive social interaction adding to a negative mood.
Chickens show depression via lethargy and reduced activity (less foraging, scratching, and social interaction), loss of appetite and water intake. They will hide or isolate from the flock. Female chickens will have changes in egg production, with potential excessive preening or feather plucking, and changes in droppings.
Pigs may show depression-like states via prolonged inactivity, reduced motivation and exploration, social withdrawal, changes in vocalisations, loss of appetite, and overall withdrawal from previously enjoyed activities. In other words, depression in pigs looks a lot like depression in humans.
Life on a Farm
Farm animals can exhibit signs of depression that parallel human symptoms. This is primarily observed through changes in behaviour and physiology. For instance, research by Favole et al. (2023) indicates that dairy cows in restrictive environments show biochemical changes in brain-derived neurotrophic factor (BDNF) and the kynurenine pathway, which are associated with mood disorders. These animals may exhibit depression-like states reflected in physiological changes, such as decreased fat, platelet and red blood cell levels. The cows also produced significantly less milk (Favole et al., 2023).
Demirdaş (2018) discusses how various stress models in animals, such as chronic mild stress and forced swimming tests, are used to investigate depression, showing that farm animals under chronic stress can develop depression-like behaviours (Demirdaş, 2018). Additionally, Lucki (2014) reviews animal models of depression, emphasising their role in understanding the underlying mechanisms and screening potential treatments. This review found that farm animals demonstrate similar symptoms when exposed to adverse conditions to induce chronic stress (Lucki, 2014).
Paper Title | Insight |
Indicates that dairy cows in restrictive environments show biochemical changes associated with depression. | |
Describes various stress models used to induce depression-like behaviours in animals, relevant for farm animals under chronic stress. | |
Reviews animal models for studying depression, highlighting their use in understanding mechanisms and treatments, applicable to farm animals. | |
Examines mental health issues among livestock farmers, indirectly suggesting the stress and mental health impact on livestock. | |
Uses murine models to explore dietary impacts on depression, implying similar potential in farm animals. |
Animal Welfare?
Depression in farm animals can have significant implications for animal agriculture on multiple levels. Here are some key points to consider:
Health and Welfare Concerns: Depressed animals may exhibit changes in behaviour, appetite, and overall well-being. This can lead to decreased productivity, compromised immune systems, and increased susceptibility to diseases. In turn, this can impact the overall health and welfare standards of the animals within the agriculture system, with increased use of antibiotics and other drugs.
Production Efficiency: Depressed animals may not eat or drink as much as healthy ones, leading to reduced growth rates and lower production efficiency. For example, in dairy cows, depression can lead to decreased milk production. In poultry, it can result in reduced egg production or slower growth rates in broilers.
Economic Impact: Reduced productivity and efficiency directly affect the economic viability of animal agriculture operations. Farmers may incur higher costs for veterinary care, medication, and feed without the corresponding returns in terms of meat, milk, or other animal products.
Reputation and Consumer Perception: Concerns about animal welfare and mental health in agriculture have gained significant attention in recent years. Reports of depressed or mistreated animals can lead to public backlash, tarnishing the reputation of the agricultural industry and potentially affecting consumer confidence and purchasing decisions.
Regulatory and Ethical Considerations: Depressed animals may raise ethical concerns about the treatment of animals within the agricultural system. This can lead to increased scrutiny from regulatory bodies and calls for stricter enforcement of animal welfare standards.
Addressing depression in farm animals requires the ending of animal agriculture. There is no way to breed, raise and kill animals on the current scale that is stress-free for them. Males are manipulated to produce sperm, and females are maltreated in the process of being impregnated. Sows are kept in crates and cages, unable to walk or even turn around, as they are used as baby-making machines. Heifers in the dairy industry have their calves taken away after birth so that they don't get the milk made for them. The list of abuses is long.
The Implications
The implications of depression in farm animals for veganism can be profound and reinforce several key arguments and concerns within the vegan movement:
Ethical Considerations: Veganism is often motivated by ethical concerns about animal welfare and suffering. The presence of depression in farm animals underscores the ethical dilemmas inherent in animal agriculture, where animals experience mental distress due to confinement, stress, and other factors associated with intensive farming practices.
Health and Nutrition: Veganism promotes plant-based diets as a way to improve health and reduce the risk of chronic diseases. The health implications of depression in farm animals further support arguments for transitioning to a plant-based diet, as it highlights concerns about the quality and safety of animal products derived from stressed or unhealthy animals.
Environmental Impact: Animal agriculture is a major contributor to environmental degradation, including deforestation, water pollution, and greenhouse gas emissions. Depressed animals may have reduced productivity, leading to increased resource consumption per unit of output and exacerbating the environmental footprint of animal farming. Veganism, as a diet that relies solely on plant-based foods, is a more sustainable alternative with lower environmental impact.
Consumer Awareness and Choices: Awareness of the mental health and welfare issues faced by farm animals can influence consumer attitudes and choices. Concerns about animal welfare, including depression, may prompt individuals to reconsider their consumption habits and opt for plant-based alternatives or products from sources that adhere to higher animal welfare standards.
Advocacy and Activism: Understanding the mental well-being of farm animals can strengthen advocacy efforts aimed at promoting veganism and improving animal welfare standards within the agricultural industry. It provides additional evidence to support arguments for transitioning away from animal-based food systems and toward more compassionate and sustainable alternatives.
In summary, depression in farm animals is real. Just as we suffer, so do they. This serves as a compelling factor that aligns with the core principles and motivations behind veganism, including ethical concerns, health considerations, environmental sustainability, consumer awareness, and advocacy for animal welfare.
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