How severe is too severe?


Source: Flickr/ Creativ92

In the last post I wrote about the large number of animals used for scientific purposes – just under 7 million animals in Australia in 2014. In this post, I will look at the impact on the animals, or rather what we know about the pain and suffering imposed on animals used in research and teaching.

Australia maintains no national collection of animal use data, but Humane Research Australia (HRA) collects annual statistics from the states and makes them available online. The latest available statistics are from 2014 and only available from four states (Victoria, New South Wales, Tasmania, Western Australia). These statistics tell us about the numbers of animals used by state, by species, by project purpose and by procedure severity.

Most animals are subjected to what researchers describe as observation or minor interventions. But in Australia in 2014 there were nearly 190,000 animals who were subjected to “major physiological challenge”, and 26,397 suffered “death as endpoint” – and these are only the numbers we know from four states. South Australia, Queensland, the Australian Capital Territory and the Northern Territory do not provide animal use data.

Death as an endpoint does not mean any type of death. Here is the definition from the National Health and Medical Research Council’s Australian code for the care and use of animals for scientific purposes. 8th Edition:

Death as an endpoint: when the death of an animal is the deliberate measure used for evaluating biological or chemical processes, responses or effects—that is, the investigator will not intervene to kill the animal humanely before death occurs in the course of a scientific activity. ‘Death as an endpoint’ does not include the death of an animal by natural causes or accidents, or the humane killing of an animal as planned in a project or because of the condition of the animal.

In other words, death as an endpoint means that a study involves some form of experiment where the animal is observed until death occurs, without providing pain relief.

For example, the LD50 test involves groups of animals being exposed to increasing doses of a toxic substance or infection with a disease to determine the dose required to kill 50% of the animals. The animals do not receive any pain relief. In contrast, the term “humane endpoint” means a procedure whose endpoint is death, but the animal’s pain or distress is alleviated.

A “major physiological challenge” might involve

  •   major infection
  •   major phenotypic modification
  •    oncogenesis without pain alleviation
  •    arthritis studies with no pain alleviation
  •    uncontrolled metabolic disease
  •    isolation or environmental deprivation for extended periods
  •    monoclonal antibody raising in mice

(University of New England. You can find examples for other severity categories on this web page as well. Other Australian universities provide similar guidance for categorising the severity of experimental procedures.)

But even some of the procedures categorised as “mild” or “minor” don’t sound mild or minor to me. For example, the European Commission published a report by an Expert working group on severity classification of scientific procedures performed on animals that includes in the “mild” category procedures such as gavage (force-feeding), induction of tumours, intravenous administration of substances and short-term (<24 hours) restraint in metabolic cages. Metabolic cages allow for accurate monitoring of waste production (urine, faeces).

Besides, why would metabolic cages be used if the stress experienced in these cages has been found to compromise research results? A study published in PLOS ONE found that the condition of mice in these cages “cannot be considered representative of a normal physiology”. Further, the authors of the study wrote:

“Similarly elevated HPA axis activity, persisting for as long as three weeks, is rarely encountered in literature; in our laboratory we have not previously encountered a stress response of this magnitude. The overall physiology of these animals must be considered severely affected, making them a poor model for most experimental studies.”

If you want to see how mice are force-fed, this video shows mouse oral gavage training.


The production of genetically modified animals is increasing. They are mainly mice and rats who have been genetically manipulated to “model” different types of diseases. Chicken, pigs, sheep, cattle have been genetically altered to increase their production of meat, milk or eggs.


GFP transgenic mice. Source: Wikimedia Commons/ Ingrid Moen, Charlotte Jevne, Jian Wang, Karl-Henning Kalland, Martha Chekenya, Lars A Akslen, Linda Sleire, Per Ø Enger, Rolf K Reed, Anne M Øyan and Linda EB Stuhr: Gene expression in tumor cells and stroma in dsRed 4T1 tumors in eGFP-expressing mice with and without enhanced oxygenation. In: BMC Cancer. 2012, 12:21.

The production of GM animals involves high numbers of “wastage”. Up to 54 animals die for the creation of a single genetically modified animal. This is how AnimalAid describes the process:

In order to create a new strain of transgenic mice, young females are injected with powerful hormones to make them superovulate. After mating, they are killed to extract the embryos, which are microinjected with the foreign DNA. These altered embryos are then surgically implanted into many surrogate mothers, who have also been hormone-injected to assist implantation and who will later be killed before or after giving birth. Many of the resulting baby mice are malformed and die before or shortly after birth. The surviving babies have to be tested to see if they have the new gene: this can be done by saliva or faecal sampling but is more often conducted by cutting off the tips of their tails or a notch from their ears.

Only 1-10% of the baby mice will have successfully incorporated the new gene. The other 90-99% will be destroyed as ‘failures’. This translates into so much killing that many of the animal technicians responsible for killing all the ‘waste’ animals find it traumatic and are left feeling ‘physically and emotionally exhausted’. While hundreds of animals are sacrificed to produce a new transgenic ‘model’, life for the survivors can be even worse than for the failures.

AnimalAid is an animal rights organisation from whom we might expect a critical view of the genetic engineering of animals. But academics broadly in support of this practice offer words of caution as well. The following is from an article in the Canadian Veterinary Journal:

Although genetic engineering may provide substantial benefits in areas such as biomedical science and food production, the creation and use of genetically engineered animals not only challenge the Three Rs principles, but may also raise ethical issues that go beyond considerations of animal health, animal welfare, and the Three Rs, opening up issues relating to animal integrity and/or dignity. Consequently, even if animal welfare can be satisfactorily safeguarded, intrinsic ethical concerns about the genetic engineering of animals may be cause enough to restrict certain types of genetically engineered animals from reaching their intended commercial application. Given the complexity of views regarding genetic engineering, it is valuable to involve all stakeholders in discussions about the applications of this technology.

Animals in labs suffer not only from experimental procedures, but also from life in the laboratory. They might live in barren cages, be isolated from other animals or live in overcrowded cages, never experience sunshine, or live in bright light contrary to their natural habits. Daily life in the lab – with fear, boredom and confinement – is stressful enough without experimental interventions that bring additional suffering.

The standard housing temperatures for mice in labs, for example, are much lower than is comfortable for the mice. Some researchers have argued that this causes cold stress which has implications for tumour growth and immunity.

Most of the procedures that go beyond observation only would be considered animal cruelty if they were performed outside the lab and without the prospect of improving the health and wellbeing of the animal (for example, surgery in a veterinary clinic). Given that all this is done as part of an ever increasing industry without much, if any, benefit for either human or non-human animals, it is morally wrong and bad science.




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