In the public eye, animal testing on so-called "farm animals" is often presented as a necessary measure for the animals' health and well-being. It is suggested that such experiments serve to prevent disease, minimize suffering, or improve living conditions. However, this portrayal is misleading and conceals the true motives behind the research. The actual goal is to maximize the animals’ "productivity" and minimize economic losses. "Performance" is measured in liters of milk produced, daily weight gain, or simply in the survival of as many animals as possible. The welfare of the individual animal is secondary to the aim of maintaining livestock as an economic resource and maximizing production efficiency.

"Livestock" Farming: A System of Exploitation

So-called "livestock" farming is used to produce food (e.g., milk, meat, eggs), as well as other animal products (e.g., wool, leather, fur, and feathers). The primary goal is the systematic breeding of animals for extreme performance to maximize their productivity (1). In this context, the animals' health is merely a means to an end.

At the end of 2024, there were 10.5 million cattle, 21.3 million pigs, and 1.5 million sheep in Germany. The poultry population in 2023 amounted to 167 million animals (1).

To enable high numbers of animal product output, "livestock" are often kept in severely restricted spaces in what is known as factory farming. For the operators, this has the advantage of reducing the labor required for animal care and feeding, and of allowing the use of automated housing systems. For the animals, however, this means - in addition to being treated as mere commodities - no individual care or regard for their species-specific needs, and, above all, constant stress.

Even more milk: The central objective is the systematic breeding of animals for extreme performance.

The Numbers Behind Suffering: Scope and Purpose of Animal Testing on "Livestock"

According to official statistics from the German Federal Institute for Risk Assessment (BfR), in 2023, 13,811 domestic chickens, 10,577 pigs, 2,797 turkeys, 2,481 cattle, 2,114 sheep, and 172 goats were "used" in animal experiments or killed for scientific purposes. Exact numbers for ducks and geese are not available in the statistics, as they fall under "other birds" (9,129 animals in 2023) (2).

Like almost every animal species, "livestock" breeds also suffer and die for basic research - for example, pigs in cardiovascular research, sheep in orthopedics, or chickens in neurology (3). Statistically, however, most experiments involving "livestock" are primarily classified as applied research focusing on animal diseases, animal nutrition, animal welfare. In 2023, 2,638 domestic chickens, 2,256 pigs, 2,199 turkeys, 974 cattle, 365 sheep, and 23 goats were used in this category. As in the overall numbers, the figures for ducks and geese cannot be precisely determined here either, as they fall under "other birds" (202 animals) (2).

These official numbers do not reflect the full extent of the suffering. A fundamental problem with the statistics lies in the legal definition of animal experiments, which excludes many animals that are manipulated and killed for research purposes. In particular, a large portion of the embryos used, manipulated, and discarded in reproductive research do not appear in official statistics. For animal experiments on mammal embryos, there is a legal gray area, as they are only considered animal experiments during the final third of the pregnancy. For birds, this only applies if the animals hatch and are likely to suffer pain, distress, or harm (4).

Research Areas in Detail: Examples of Livestock Experiments

Research on "livestock" does not focus on individual animals but on entire populations. The goal is to achieve the highest possible quality and quantity of animal-based food and products through targeted breeding and adjustments in housing and feeding strategies. Other priorities include protecting the livestock population as an economic resource and reducing labor and production costs. The experiments conducted mainly fall into the fields of animal breeding, animal nutrition, animal husbandry, and infectious disease research.

Animal Breeding & Reproduction

Within the context of "livestock”, animal breeding aims for the targeted modification of genetic traits, for example, to increase milk yield or reduce fearful behavior. To achieve these breeding goals more quickly, reproductive techniques such as artificial insemination or embryo transfer are used. Strategies to reduce the number of surplus male animals also fall into this category.

Livestock breeding research is often presented as a contribution to animal welfare, for example, by claiming to avoid painful procedures such as castration. A closer look, however, reveals that the real cause is not inefficient reproduction but the specialization of breeding for extreme performance (5).

This mass production strategy leads to health problems in female animals and creates "waste products": male animals that are useless for the respective breeding goal. A well-known example are male chicks in egg-laying hen breeding, which are neither suitable for egg laying nor for meat production. The same applies to calves from dairy breeds.

Reproductive research attempts to solve this problem by, for example, influencing the offspring’s sex before birth or suppressing reproductive capacity. Yet the suffering merely shifts from killing or castration to genetic manipulation and hormonal stress.

Examples of Animal Experiments from the Research Area of "Animal Breeding"

An experiment was conducted to investigate whether genetically male pigs could be modified to develop female reproductive organs. According to the authors, the results of this study serve animal welfare, as this could make the castration of male piglets unnecessary. To this end, eggs were fertilized in vitro and manipulated 20 hours later with CRISPR gene editing scissors. A total of 63 and 166 embryos were transplanted into hormonally treated sows. Only a few piglets resulted from these experiments, some of which were genetically male but phenotypically female. These animals suffer from growth disorders, underwent repeated, unsuccessful hormone treatments, and were ultimately killed at 2 months of age to examine their organs (6).

A test on 8 male goats examined whether a hormone can suppress their reproductive ability. The animals receive daily hormone treatments for seven weeks. Their testicles were repeatedly examined by ultrasound, blood samples were taken from the jugular vein, and semen was collected using an artificial vagina. At the end of the experiment, all animals are castrated (7).

In an experiment involving 178 chickens, researchers aimed to determine how different breeds vary in their fearfulness in order to breed “less fearful” animals.  Over a 14-day period, the animals were transported up to 38 times to an "arena" where they were placed on their backs and held to measure the duration of their tonic immobility (fear paralysis) (8).

An experiment on 119 Japanese quails investigated whether their extremely high egg-laying rate of up to 300 eggs per year causes damage to the breastbone. The animals were regularly caught, weighed, and fixed upside down in a frame for X-rays. During the experimental period, 10 of the 51 female animals die from diseases, egg-laying difficulties, or injuries. Among the surviving animals, more than 80% showed deformities of the keel bone, and all were killed at the end of the study to examine their bones.

Animal Nutrition

Animal experiments in "livestock" nutrition are officially justified as being necessary to ensure feed and food safety, improve animal health, and enhance product quality (10). However, this research primarily serves economic goals. A crucial factor in making the production of animal-based foods like meat, milk, and eggs cost-effective is feed, which accounts for a significant portion of the total production costs. In this context, animal nutrition research strives to maximize the animals' nutrient absorption and utilization (11–15). The experiments are therefore designed to optimize feed composition to achieve the greatest possible production benefit. They also investigate the influence of contamination on the animals' health - not for the animals’ well-being, but rather in terms of their productivity or the risk that contaminants might enter animal products and thereby harm humans.

Examples of Animal Experiments from the Research Area of "Animal Nutrition"

Due to the rapidly increasing calcium demand from milk production, many so-called dairy cows suffer from a life-threatening calcium deficiency after giving birth. In an experiment with 70 pregnant cows, the influence of a plant-based lipid mixture on calcium absorption was investigated. The cows were divided into two groups: an experimental group receiving lipids in addition to their normal feed and a control group. The animals are milked by a robotic milking system and their "milk yield" was recorded. Blood samples were taken regularly, and the animals' physical condition was assessed. A partially severe calcium deficiency was found in 18 cows (16).

To determine how the calcium content of feed affects phosphorus digestibility, 8 boars were operated on. A tubular device was implanted in their small intestine, allowing samples of the intestinal contents to be collected externally. The boars were kept individually in so-called metabolism chambers and received one of four feed mixtures with different calcium contents for twelve days. Feces and urine are collected daily, and a blood sample is taken at the end of the experiment (17).

An experiment with 640 male chickens investigated how different feed compositions—especially zinc levels—affect bone mineralization and zinc status. The animals were kept in groups of 10 in pens with perforated floors to prevent them from eating their feces. Nine roosters died during the experiment. At the end, all animals were killed, some by decapitation, the others by carbon dioxide asphyxiation, and tissue samples, including intestinal contents, shins, and feet, were collected for analysis (18).

15 pigs are divided into groups to investigate the transfer of polychlorinated biphenyls (PCBs) from contaminated feed to their tissue. PCBs, which are used as plasticizers, are considered potentially carcinogenic. The animals received PCB-contaminated and normal feed in different feeding schemes. Feed intake, weight development, stool consistency, and the animals' behavior were monitored over the entire 81-day experimental. At the end, all pigs are killed and tissue samples were taken to measure the PCB content (19).

Ten high-yielding cows were grouped to assess how feed composition influences the absorption of the mold toxin aflatoxin and its concentration in milk. The animals received different feed mixtures for 4 weeks and on some days a gelatin capsule with aflatoxin. Milk yield, feed intake, and behavior were monitored, and milk samples were analyzed. The further fate of the animals was not mentioned (20).

102 chickens were used in experiments on the transfer of polychlorinated biphenyls (PCBs) from feed and soil. Some hens received contaminated feed for varying periods before being switched to uncontaminated feed, and their eggs were analyzed. Other hens are kept on soil with different PCB levels. Eggs were collected, and at different times, the animals were killed to collect muscle samples. Feed intake, egg production, and health status were monitored throughout the experiment (21).

Animal Husbandry

Keeping “livestock” in large numbers and under extremely confined conditions is anything but species-appropriate problems such as stress, aggression, and injuries are inevitable. Within this context, the research area of "animal husbandry" presents itself as a supposed problem solver. Its official purpose is to address existing issues by investigating "various housing systems and the benefits of so-called enrichments in the cages" (22). This is supposed to improve "animal welfare," but the real goal of this research is to maintain and legitimize the problematic system instead of fundamentally questioning or abolishing it.

Animal experiments on "lifestock" is not aimed at ending suffering of animals but at optimizing and legitimizing a system of animal exploitation.

Examples of Animal Experiments from the Research Area of "Animal Husbandry"

1,200 broiler chickens were used to test the influence of an elevated platform with integrated weighing scales. The aim was to obtain data on the animals' weight and activity and to evaluate the platform as supposed "enrichment". The animals were kept in groups of 200 in pens of 15-square-meter. In addition to feed and water, the pens contained a 4-meter-long plastic grid platform, placed half a meter above the ground and accessible via ramps. During the five-week experimental period, the chickens' movements on the platform were documented by video camera, and their weight was automatically monitored. For a subgroup, it was also measured manually several times, which required catching the animals each time. Some animals fell ill during the study and were treated with antibiotics for several days. The further fate of the chickens was not mentioned (23).

9 quails were used to analyze their movement sequences while climbing steps. The animals repeatedly had to cross a three-meter-long corridor, the floor of which was either flat or had a step of 1 to 5 centimeters in the middle. Their movements were recorded using high-speed cameras and X-rays from the side and below. The recordings were then used to create a computer-based model of the animals' locomotion (24).

A study investigated how housing conditions for female turkeys in monotonous pens change with an additional structure—the so-called “turkey tree.” For this purpose, 132 turkey chicks were raised in 6 groups of 22 animals each in pens of 5.4 square meters. Some of the pens were equipped with the “turkey tree,” consisting of three platforms at different heights, while the control group was kept without any additional structure. Over 88 days, blood was drawn from the turkeys' wing veins four times in total. Their behavior, use of the platforms, and aggression towards conspecifics were recorded via video surveillance and their plumage was checked for injuries. During the experiment, four animals died or were killed. At the end, the remaining birds were stunned with an electric shock and then bled out (25).

In a study with 1,344 hens of different breeds, the factors contributing to damage to the breastbone were investigated. The animals were kept either individually in cages of less than 0.24 square meters or in groups of 24 in larger pens. The hens were weighed regularly and examined for keel bone deformities and fractures while being held upside down. After 70 weeks, they were killed with carbon dioxide so that the breastbones and attached muscle tissue could be removed and analyzed.  Clear differences were observed depending on the breed and housing type: between 14 and 97 percent of the animals showed breastbone deformations, and about 39 percent suffer at least one fracture (26).

Infectious Disease Research

Infectious disease research on "livestock" aims to understand and prevent the spread of diseases. However, this research focuses less on the individual animal and more on avoiding economic losses caused by animal epidemics—and, in the case of zoonoses, on protecting humans(27). What is often left out of this narrative is the fundamental fact that industrial factory farming itself is the main cause of the emergence and spread of such diseases. The extremely high animal density, the lack of space, and poor hygiene create ideal conditions for the emergence of zoonoses and the development of antibiotic-resistant germs that also threaten human health (28,29). Global trade, in which animals are transported over long distances and across country borders, further contributes to the spread of epidemics (29).

The industrial factory farming itself is the main cause of the emergence and spread of such infectious diseases. ©WEanimals

Examples of Animal Experiments from the Research Area of “Infectious Diseases”

In one experiment, 20 sows were infected with a weakened strain of the African swine fever (ASF). Within a few days, most animals showed fever and clinical symptoms such as reduced activity and appetite. Within 28 days after infection, 15 of the sows either died or were killed. The 5 surviving sows were then artificially inseminated. Some of their piglets were infected at seven days old with a highly contagious ASF strain. They died within 9 days or were killed. Other piglets were not infected; instead, blood samples were  taken from them weekly (30).

In another study, 45 turkeys were infected with either genetically modified or unmodified avian influenza viruses, which were applied to their eyes. After 24 hours, healthy turkeys were introduced as a contact group to study the transmission. The animals were evaluated daily using a scoring system that recorded symptoms such as respiratory problems, diarrhea, and neurological disorders. Within a few days, the turkeys showed the most severe illnesses, including ruffled feathers, apathy, and nervous system failures. All animals either died within five days or were killed prematurely. All contact birds also died within a few days. Tissue analysis revealed severe organ damage, especially in the brain, heart, kidneys, and respiratory tract. No animal survived until the planned end of the experiment (31).

In another experiment, 30 chickens and numerous chicken embryos were used to study the role of a specific protein in infection with avian influenza virus. Seven-week-old chickens were infected in groups with either an unmodified or a genetically modified virus via their eyes and nose. After one day, healthy animals were added as a contact group. Swabs and blood samples are taken regularly. Within a few days, the chickens developed severe symptoms such as diarrhea, coordination problems, and neurological failure. Animals that could no longer eat on their own were killed. All chickens infected with the unmodified virus died within a week, while three in the modified-virus group survived until day 10. These were finally killed with an anesthetic gas, as were numerous chicken embryos shortly before hatching. Organs such as kidneys and urinary bladders were removed from the embryos, resulting in their death (32).

Various variants of the avian influenza virus were first propagated in fertilized chicken eggs, for which the embryos are killed and examined. Subsequently, 40 chickens were infected either via intravenous injection or, in the case of day-old chicks, directly into the brain. Anesthesia was not mentioned. The animals were observed for several days and examined for signs of disease. After a short time already, some showed severe neurological symptoms and either died or were killed. The experiment was particularly drastic for the chicks: in one group, all animals died within 2-3 days.  In the other, some died, while the surviving chicks were also killed after 8 days. It must be assumed that the adult chickens were likewise killed at the end of the experiment (33).

16 sheep were infected with two different sheep pox viruses. Depending on the group, the animals received the virus via injection, through the nose, or by contact with infected conspecifics. For 28 days, blood and swab samples were collected and symptoms documented. Within just a few days, nearly all sheep developed high fever, severe nasal and eye discharge, respiratory difficulties, and skin lesions. One animal died on day 7; the others became so severely ill that they were killed during the experiment. After 28 days, the last surviving sheep were killed, so that organs such as the lungs, spleen, and lymph nodes could be removed for examination (34).

Conclusion

The claim that animal experiments on so-called "livestock" serve animal welfare is at odds with the reality of practice. This research is not aimed at ending suffering but at optimizing and legitimizing a system of animal exploitation in which animals are treated purely as means of production. Their health and well-being are considered only when it serves the goal of maximizing profit.

This system is ethically unjustifiable, and poses a significant risk to public health, as it promotes the emergence and spread of diseases.

The logical consequence is to fundamentally break away from this system. Real change requires the abolition of factory farming and the end of using of animals as economic commodities. As long as animals are kept as a means of production, the problems that this research claims to solve—such as diseases, suffering, and inefficiency—will persist. The system itself creates the very problems it pretends to address. The change of the system is therefore the only effective solution to the problems created by the industry itself.

Research truly aimed at the welfare of individual animals is only possible within an ethically justifiable framework and can be conducted entirely with animal-free methods such as multi-organ chips and organoids. The future lies in creating a system based on ethics, science, and sustainability.

13/10/2025
Dr Gaby Neumann, DVM

References

1. Landwirtschaft: Tierhaltung. Bundesministerium für Landwirtschaft, Ernährung und Heimat (BMLEH) (abgerufen am 10.09.2025)
2. Deutsches Zentrum zum Schutz von Versuchstieren (Bf3R): Versuchstierzahlen 2023
3. Datenbank Tierversuche. Ärzte gegen Tierversuche, www.datenbank-tierversuche.de (abgerufen am 10.09.2025)
4. TierSchVersV - Verordnung zum Schutz von zu Versuchszwecken oder zu anderen wissenschaftlichen Zwecken verwendeten Tieren, Stand 11.08.2021
5. Tierzucht. Bundesinstitut für Ernährung und Landwirtschaft (BMEL), 3.5.2023
6. Kurtz S. et al. Knockout of the HMG domain of the porcine SRY gene causes sex reversal in gene-edited pigs. Proceedings of the National Academy of Sciences 2021; 118(2):e2008743118
7. Mihsler-Kirsch L. et al. Downregulation of testicular function in the goat by altrenogest. BMC Veterinary Research 2021; 17(1):183
8. Tiemann I. et al. Differences among domestic chicken breeds in tonic immobility responses as a measure of fearfulness. PeerJ 2023; 11:e14703
9. Hildebrand L. et al. Japanese quails (Coturnix Japonica) show keel bone damage during the laying period—a radiography study. Frontiers in Physiology 2024; 15
10. Ziele und Aufgaben. HBLFA Raumberg-Gumpenstein, Institut für Nutztierforschung  (abgerufen am 10.09.2025)
11. Klemme, J. Entwicklung der Ernährungsforschung bei Wiederkäuern im 19. Jahrhundert. Dissertation Tierärztliche Hochschule Hannover, 2003
12. Vinyeta E. Auswirkungen der Futterzusammensetzung auf den Nährwert. 3tres.com, 16.10.2020
13. Futtereffizienz. ForFarmers Deutschland, 25.05.2023
14. Geflügelfütterung. Deutscher Verband Tiernahrung (abgerufen am 10.09.2025)
15. Nährstoffangepasste Ökofütterung im Mastversuch. Landwirtschaftskammer Niedersachsen, 24.02.2022
16. Ott D. et al. Blood calcium concentration and performance in periparturient and early lactating dairy cows is influenced by plant bioactive lipid compounds. Journal of Dairy Science 2023; 106(5):3706–3718
17. Effect of dietary calcium concentration and exogenous phytase on inositol phosphate degradation, mineral digestibility, and gut microbiota in growing pigs | Journal of Animal Science 2023; doi:10.1093/jas/skad254
18. Philippi H. et al. Effect of dietary zinc source, zinc concentration, and exogenous phytase on intestinal phytate degradation products, bone mineralization, and zinc status of broiler chickens. Poultry Science 2023; 102(12):103160
19.  Moenning J.-L. et al. Toxicokinetic modelling of the transfer of non-dioxin like polychlorinated biphenyls from feed into edible tissues of pigs. Science of The Total Environment 2023; 892:164539
20. Walte H.-G. et al. Re-evaluation of aflatoxin M1 transfer into milk of high-yielding cows considering ration composition. Journal of Animal and Feed Sciences 2022; 31(4):343–351
21. Ohlhoff B. et al. Transfer of Non-Dioxin-Like Polychlorinated Biphenyls (ndl-PCBs) from Feed and Soil into Hen Eggs. Journal of Agricultural and Food Chemistry 2022; 70(29):8955–8962
22. Bundesprogramm Nutztierhaltung BUNTH. Bundesinformationszentrum Landwirtschaft (abgerufen am 10.09.2025)
23. Schomburg H. et al. Elevated platforms with integrated weighing beams allow automatic monitoring of usage and activity in broiler chickens. Smart Agricultural Technology 2023; 3:100095
24. Andrada E. et al. Limb, joint and pelvic kinematic control in the quail coping with steps upwards and downwards. Scientific Reports 2022; 12(1):15901
25. Lindenwald R. et al. Influence of environmental enrichment on circulating white blood cell counts and behavior of female turkeys. Poultry Science 2021; 100(9):101360
26. Habig C. et al. Keel bone damage in laying hens—its relation to bone mineral density, body growth rate and laying performance. Animals 2021; 11(6):1546
27. Tiergesundheit. Europäische Behörde für Lebensmittelsicherheit (EFSA) (abgerufen am 10.09.2025)
28. BUND-Studie - Massentierhaltung fördert antibiotikaresistente Keime. Deutschlandfunk, 12.01.2015
29. Der Zusammenhang zwischen Nutztierhaltung, viralen Zoonosen und globalen Pandemien. Human Society International – Europe, 01.09.2020
30. Friedrichs V. et al. Maternal immunity and African swine fever virus: understanding the limits of passive protection. Frontiers in Immunology 2025; 16
31. Kuryshko M. et al. In turkeys, unlike chickens, the non-structural NS1 protein does not play a significant role in the replication and tissue tropism of the H7N1 avian influenza virus. Virulence 2024; 15(1):2379371
32. Hohensee L. et al. The role of PB1-F2 in adaptation of high pathogenicity avian influenza virus H7N7 in chickens. Veterinary Research 2024; 55(1):5
33. Schön J. et al. Neuraminidase-associated plasminogen recruitment enables systemic spread of natural avian Influenza viruses H3N1. PLOS Pathogens 2021; 17(4):e1009490
34. Wolff J. et al. Establishment of a challenge model for Sheeppox virus infection. Microorganisms 2020; 8(12):2001