by Kevin McElhatton
Over the course of many generations, humans have artificially selected animals in order to make them more fit for consumption. Upon doing so, humans have caused these domesticated animals to become less fit to survive on their own, raising this important question: Was this choice to artificially select animals ethical? As a result of domesticating animals by “raising them in captive conditions, the genetic structure of these animals is altered in long term by a process known as relaxation of natural selection” (Pazhoohi 2011, p. 214). Along with the questionable ethics of domestication, the purpose of this artificial selection is also a problem since physical and psychological stress can cause a deterioration in the health of animals, especially ones raised for slaughter. This process is thought by some to be moral since it is directly beneficial to humans, but this assumption is misguided and untrue. The negative traits accumulated through this process impair the welfare of these animals and outweigh the “good” traits that are specifically selected. Although it has provided some benefits for humans, the domestication of animals through the use of artificial selection is unethical as it has sometimes been detrimental to the animals’ well-being.
Artificial selection, a term first coined by Charles Darwin in his book On the Origin of Species, is defined as taking traits created through natural selection and combining the ones that are useful to benefit humans (Darwin 1859). Pazhoohi states that “human inadvertent selection for domestication correlated traits may cause regression of certain organ or change in certain behavior of animal” (Pazhoohi 2011, p. 214). As shown by Pazhoohi in his essay, the process of domesticating an animal is detrimental to the species undergoing the domestication. This process, although beneficial to society, is unethical as it benefits humans at the cost of these animals’ wellbeing. Scott Newman, the author of Quantitative- and Molecular-genetic Effects on Animal Well-being: Adaptive Mechanisms, suggests that domesticating animals requires a change in behavior on a genetic level meaning that the animals must be placed in an unfamiliar environment to be adapted to suit the humans’ needs, and then goes on to further explain what traits favor or resist domestication (Newman 1994). This process is immoral as it induces fear and anxiety in whatever animals are being subjected to a new environment. On top of this, artificial selection can have detrimental effects on these animals, such as obesity, diseases, health disorders, and can even lead to smaller brain size.
Artificial Selection Leads to Fear
In his article, Newman looked at the effects of artificially selecting for the double muscling gene in cows and bulls. Newman states that selecting for this gene “may cause reduced fertility and severe dystocia, but higher growth and superior carcass characteristics compared with normal cattle. Behavioral differences between normal and heterozygous and homozygous double-muscled animals have been reported, whereby cattle homozygous for muscular hypertrophy have been found to be more fearful than heterozygotes, which, in turn, were more fearful than homozygous normals” (Newman 1994, p. 1648). Not only were these cows and bulls living with a condition detrimental to their ultimate needs, such as reproduction, they were passing this detrimental condition on to their offspring. Along with this, they were subjected to more stress due to their increased fear to the extent that fear jeopardized their welfare.
Along with fear, artificial selection can bring unwanted traits. For sheep, selecting for increased fleece weight and lamb growth has been shown to cause an increase in fecal egg counts in Romney sheep (Morris et al. 1996). However, artificially selecting for reduced fecal egg count showed to increase fat depth in Merino sheep (Pallott and Greeff 2004). Pazhoohi makes it quite clear that these undesired traits that arise through artificial selection compromise the well-being of these animals. Pazhoohi states that “domestic fowls which are selected for growth are phlegmatic and have excessive appetites and reduced motor ability. This enhances the propensity for obesity and affects their well-being. Intensive selection for higher growth rate in broilers was negatively correlated with increasing the incident of ascites syndrome and caused leg problems” (Pazhoohi 2011, p. 216). Similar to humans, obesity in nonhuman animals harms the well-being of animals. Since the artificial selection in fowls for increased growth causes obesity, it is evident that the artificial selection is detrimental and immoral to the fowls who are not slaughtered at a very young age. Along with the obesity, Pazhoohi mentions that there is “a genetic trend of decreasing heart weight in broiler line which can cause higher mortality rate. In comparison to fast growing, slow growing strains of chickens had better locomotor activity and lower mortality rates” (Pazhoohi 2011, p. 216). In these broiler chickens, the higher rate of mortality is a symptom of a reduced welfare.
One specific animal that has been artificially selected to the point where it can no longer reproduce on its own is the turkey. Turkeys have been bred for more meat so that they provide more money per bird, though this has caused turkeys to become “physically incapable of mating, necessitating artiﬁcial insemination via tube or syringe” (Greger 2011, p. 455). The cause of this incapability to breed is that their size is too large for them to stay mounted while mating, preventing turkeys from reproducing. Because of this unethical artificial selection for more meat, Broad Breasted White and Broad Breasted Bronze turkeys would go extinct without the aid of human management. However, the inability to breed is not the only harm done to turkeys because of artificial selection. As a result of breeding turkeys for more meat, these turkeys are more likely to die from sudden death syndrome as well as have health problems such as suffering from hip problems (Greger 2011). Greger reports that the majority of turkeys kept for breeding suffer from either abnormal gait or lameness, showing that this process of artificial selection harms both the turkey’s health as well as the breeder’s profit from his flocks (Greger 2011). He also mentions that some people consider death from heart failure from being too fat as a sign of “good flock health” (Greger 2011, p. 455). How can one say that dying from growing so fast that their heart stops is a good thing? It is highly immoral to believe that this is a good thing, as it accomplishes nothing but the death of an animal, which serves as nothing but loss to the producer.
Another animal that has been affected in a similar manner are chickens. People in the chicken industry have bred chickens to become as fat as they can as quickly as possible so that they can get the most money out of them. Karen Davis, the author of an article posted on Free From Harm, has researched the chicken industry, and states: “The chicken industry tells the public that thanks to research, better management, diet and other improvements, poultry diseases have been practically eliminated. However, industry publications and my own experience tell a totally different story. A big part of this story concerns what has been done to chickens genetically to create a heavy, fast-growing bird, falsely promoted to consumers as “healthy,” even though poultry is considered the most common cause of foodborne illness in consumer households” (Davis 2013). Karen Davis shows in her article that the welfare of chickens is compromised by artificially selecting them to be as large as they could possibly be. Animal welfare is defined by the World Health Organization as “how an animal is coping with the conditions in which it lives” (World Health Organization (OIE) 2010, p. 2). Chickens raised in poultry sheds are so greatly impacted by the artificial selection that they are unable to live a healthy life even if they are rescued as Davis shows, stating that “the pathologies built into the bird will emerge in the form of cardiovascular disease, crippled joints, and an unnatural gait. The breast muscle grows large and pendulous, and excess fat squeezes the internal organs, impairing the bird’s ability to breathe. Respiratory distress is innate in these birds. In the 1970s, a chicken farmer wrote, ironically, about the new type of chicken then being bred, that ‘the sign of a good meat flock is the number of birds dying from heart attacks.’ This remains true today” (Davis 2013). These genetic impairments usually appear in the form of a disproportional body in infancy because “they are artificially manipulated through genetics and management techniques to produce this outcome”, not because they are receiving proper caring by their owners (Davis 2013). As a result of these impairments, the chickens are forced to live an unhealthy life.
Rauw et al. show in their article that Lacombe boars selected for high lean tissue are highly susceptible to having leg weakness in comparison to boars that have not been selected for high lean tissue (Rauw et al. 1998). The authors observe that there are “genetic correlations between production traits and leg weakness and osteochondrosis (OC) scores” (Rauw et al. 1998, p. 22). The welfare of these boars are compromised due to the weakness in their legs, as shown by the examined correlation between the production traits and leg weakness. The article also mentioned that artificial selection for productive traits led to a negative response in the immune system of animals. For example, the article stated that there was a “significantly higher percentage of mortality in turkeys selected for high 16-week body weight compared to a random-bred control line in a natural outbreak of erysipelas, 11.8 and 1.6% respectively, and when challenged with either Pasteurella multocida, 72.1 and 43.6% respectively, and Newcastle disease virus, 32.5 and 15.8% respectively” (Rauw et al. 1998, p. 19). Having a suppressed immune system would cause the turkeys to get sick more often, and to be more affected by the illnesses, as shown by the increased mortality rates. As a result, the suppressed immune system would hurt the quality of life for these turkeys. Along with the increased susceptibility to diseases in turkeys, Rauw et al. talk about the effects of artificial selection on the immune systems in broiler chickens as well. They mention how ascites, the accumulation of edematous fluid within the abdomen, is usually only found in high altitudes under hypoxic conditions. However, they also mention that this disease is becoming more common in broiler chickens in lower altitudes, such as at sea level, since approximately the 1980s (Rauw et al. 1998). The appearance of this disease in lower altitudes is an alarming sign of the extent of the effects of artificial selection in animals used for consumption. Rauw et al. state: “In The Netherlands, ascites, as a cause of mortality in broiler chickens, is increasing steadily, running parallel with a faster growth rate and, as a result, an increasing metabolic rate. A high incidence of heart failure syndrome and ascites was found in fast growing broilers exhibiting a low feed conversion ratio resulting from low values of heat production per gram body weight gain and oxygen consumption per gram deposited protein” (Rauw et al. 1998, p. 20). The parallel increase in the growth rate, metabolic rate, and ascites shows that the artificial selection for these traits is a direct cause of the ascites, and that it is not just a coincidence that there is an increase in ascites in broiler chickens.
Health Disorders and Disease Susceptibility
In their article, Rauw et al. also look at the impacts of artificial selection in cows’ health. They address the controversy of the relationship between production and health traits, stating that it was observed in “171 cows selected for high genetic potential for milk production 9% more cases of digestive disorders (20 and 11%, respectively), 5% more cases of foot rot (9 and 4%, respectively), 14% more cases of skin or skeletal disorders (49 and 35%, respectively), 11% more cases of udder edema (i.e. swelling in the mammary and adjacent tissue), and 2% more lactations affected by mastitis than 187 cows selected for low genetic potential” (Rauw et al. 1998, p. 26). These significant increases of negative qualities and diseases emphasize the horrific effects of artificial selection.
Artificially selecting animals for economic traits has been linked to reduction of animal welfare. Newman states: “Negative relationships between behaviors associated with well-being and traits of economic importance have been reported in most livestock species” (Newman 1994, p. 1641), yet producers continue to selectively breed for animals of high productivity. Newman shows in his article that inbreeding for economic traits can cause detrimental effects on animals such as cows and bulls, mentioning that it has reported that “increases in percentage of open cows and calves dead at birth and reductions in calves weaned per cow exposed as a function of increases in inbreeding coefficient. Inbred animals may also be less able to cope with their environment and may be more susceptible to diseases and environmental stresses” (Newman 1994, p. 1646). As mentioned earlier, animal welfare is defined as an animal’s ability to cope with its living conditions, therefore a lower ability to cope means that the animal’s well-being is negatively affected by the inbreeding. Subjecting animals to this process, leaving them and their offspring in a state of decay is highly unethical. Inbreeding depression, the reduction of biological fitness as a result of inbreeding, has been shown to stifle the ability to reproduce in farm animals (Newman 1994), meaning that farm animals will not only have less healthy offspring, but also be more likely to be effectively sterile.
Smaller Brain Size
Consumption of animals does not only take the form of using animals for food, but for other purposes such as using mink for their pelts. Mink artificially selected for good pelts have been shown to have smaller brains, due to “artificial selection [being able to] lead to unintended consequences when selected traits are genetically linked to other, unselected traits” (Tamlin et al. 2009, p. 266). These unselected traits pose a risk for wild mink as well. Tamlin et al. argue that “if domesticated mink hybridize with wild mink, then introgression of domestic traits such as reduced brain size might lead to outbreeding depression, if the traits are maladaptive. Indeed, reduced fitness from outbreeding depression might be an explanation for apparent declines in wild mink populations throughout Canada” (Tamlin et al. 2009, p. 267). This shows that artificial selection is more than just a threat to the welfare of domesticated animals, but to all animals with possible contact to domesticated species.
When breeding livestock, producers will look for many traits, one of which is usually the color of the animal. In his article, Per Jensen mentions that “one of the colour mutation genes was also found to have a profound effect on an important welfare-related behaviour, namely feather pecking. This is one of the most important welfare-related behavioural problems in modern egg production, where birds peck at and pull out the feathers of other individuals in the same group” (Jensen 2006, p. 11). Color, a trait which is only aesthetic and not necessary for egg production, is often selected for when artificially selecting for traits, yet as Jensen shows, this leads to feather pecking in chickens causing more harm than if producers had not selected for color. This immoral selection is only done to make the chickens aesthetically pleasing for potential buyers, all at the cost of the well-being of these chickens. Jensen looked in depth at the relation between the genetic coding of color and the behavioral display of feather pecking, stating that the birds who were homozygous for genes of non-white feathers were much more likely to be victims of feather pecking than the other birds, which had mostly white feathers (Jensen 2006). Jensen’s research shows that color plays a significant role in a fowl’s welfare, and suggests that the appearance of animals affects the behavior not only of birds, but of other animals such as “tail biting in fattening pigs and wool eating in sheep” (Jensen 2006, p. 12).
Artificial selection in animals raised for consumption is unethical and harmful to both the animals being selected as well as the producers who raise them. An unfamiliar environment is needed to domesticate animals to suit human needs, causing both psychological and physical stress. On top of the process of domestication being stressful, artificial selection has harmed animals’ wellbeing, for example turkeys who are unable to reproduce on their own because of their overly large size. Transporting these animals raised for consumption to slaughter also adds stress to these animals, even with the aid of preconditioning to attempt to mitigate the amount of stress to which these animals are subjected. Artificial selection has been a highly unethical process that has done nothing but harm to animals, all to put a few extra dollars into the pockets of the human producers.
Darwin, Charles. On the Origin of Species. London: John Murray, 1859.
Davis, Karen. Eliminating the Suffering of Chickens Bred for Meat. Free From Harm, 2013.
Greger, Michael. Transgenesis in Animal Agriculture: Addressing Animal Health and Welfare Concerns. Journal of Agricultural and Environmental Ethics, 2011.
Jensen, Per. Domestication—From Behaviour to Genes and Back Again. Applied Animal Behaviour Science, 2006.
Morris, C. A., J. N. Clarke, T. G. Watson, A. L. Wrigglesworth, and J. L. Dobbie. Faecal Egg Count and Food Intake Comparisons of Romney Single‐Trait Selection and Control Lines. New Zealand Journal of Agricultural Research, 1996.
Newman, Scott. Quantitative- and Molecular-genetic Effects on Animal Well-being: Adaptive Mechanisms. Journal of Animal Science, 1994.
Pallott and Greef. Genotype × Environment Interactions and Genetic Parameters for Fecal Egg Count and Production Traits of Merino Sheep. Katanning: Great Southern Agricultural Research Institute, 2004.
Pazhoohi, F. Intensive Artificial Selection Jeopardizes Animals’ Well-Being: A Short Review. Iranian Journal of Applied Animal Science, 2011.
Rauw, W.m, E. Kanis, E.n Noordhuizen-Stassen, and F.j Grommers. Undesirable Side Effects of Selection for High Production Efficiency in Farm Animals: A Review. Livestock Production Science, 1998.
Tamlin, Ashley L., Jeff Bowman, and David F. Hackett. Separating Wild from Domestic American Mink Neovison Vison Based on Skull Morphometries. BioOne, 2009.
World Health Organization (OIE) Definition of animal welfare, glossary. 2010. Terrestrial Animal Health Code; p. xiv.
Back to Volume 2, No. 1, Winter 2016