«October 2009 SCIENTIFIC COORDINATOR Pierre Le Neindre, Senior research scientist, INRA (French National Institute for Agricultural Research) ...»
Putting such measures into place would therefore allow some farmers, following the example of consumers, to modify their husbandry practices voluntarily and express their preferences.
A major obstacle: the World Trade Organisation’s (WTO’s) position on production methods and the absence of international standards on animal pain The WTO’s rules aim to avoid protectionist behaviour in countries, and leave little place for ethical or social demands concerning animal husbandry methods. They state that if the products are qualitatively identical, their import cannot be rejected on the grounds of production methods. In this context, better farming practices for the benefit of animal welfare are not considered to produce animal products any different from those obtained by classical industrial methods. These arguments are also valid for the question of taking animal pain into consideration at the farm level.
Only bilateral or multilateral agreements remain acceptable, but require time and sometimes difficult negotiations.
On the other hand, the adoption of international standards regarding pain in farm animals, according to the species concerned, would make a recognized international framework available. This framework would be of great use for the rationalization of voluntary measures and would become the tool of reference for the development of a rational labelling strategy, as envisaged by the European Union. There is no recognized international standard today concerning animal pain. The OIE, a competent international institution on this matter, has recently published a report on the question of pain in animals as it has previously done on animal welfare, but no official position has been defined.
Concerning animal welfare, it should be kept in mind that, six different norms have been adopted by the OIE. Five of them concern transport, (by land, air or maritime routes) or animal slaughter (for consumption or for health safety ends). The sixth concerns stray dogs.
From this analysis, it appears that there is some difficulty in taking the expectations of consumers or citizens into account on the subject of animal welfare and by extension on animal pain, at the single country level.
Expertise scientifique collective "Douleurs animales" 21
1.4. Summary The analysis of knowledge produced in the different disciplinary fields gathered together in this chapter shows a convergence of representations, knowledge and the law on recognition of animal pain which can no longer be assessed only by economic or health safety criteria. The question of animal pain has now been raised in society, by consumers and citizens. The current reference has extended to animal welfare incorporating pain in a wider framework, on the model of the definition of human health, adopted by the WHO, which now includes psychological and social components.
The current state of play on the issue is a result of multiple changes in society:
- The manner of taking human pain and by extension pain in animals into account has strongly evolved. Whereas pain was in the past considered as inevitable, solutions exist now to reduce, if not to eliminate it.
-The public has distanced itself from farm animals and farming realities. The relationship of urban populations to farm animals has become rare and the only animals with which they are in contact are pet animals, whose status is different.
- Production systems designed in the different livestock sectors of the industry in order to answer production requirements now raise multiple questions.
- The stakeholders involved in the debate have steadily increased. Whereas before, only the farmer had to take decisions, nowadays all the players in the industry, from farmers to consumers, not forgetting the retailers and also the other players, such as animal protection organizations, are all concerned in the debate.
22 Expertise scientifique collective "Douleurs animales"
2. Pain: definitions, concepts and mechanisms in humans and farm animals Although human pain involves unique features when compared to animal pain, as assessed by humans, it is obvious that the underlying neurobiological mechanisms fall along the lines of an evolutionary continuity. This chapter reviews the generic knowledge on pain that has been established by work done in humans and laboratory species. The degree to which this knowledge on pain can be transposed from man to farm animals (including mammals, gallinaceous and web-footed poultry, fish and cephalopods) is examined based on arguments ranging from phylogenetic analysis to the work on emotion in animals and to current debates on the concept of conscience in relation to pain perception. The precautions that need to be taken and the questions raised by such transpositions are discussed.
2.1. A growing scientific interest
Over the last thirty years there has been a constant growth in the total number of scientific publications on pain.
Although this output has concerned animal species as well as humans, it was only at the end of the 1970s on a global plan and at the end of the 1990s on the European level that research on pain in animals increased in earnest (Figure 1A).
There has been a steady ratio of 50:1 in the number of publications on pain reporting studies in human clinical medicine or on generic knowledge of the mechanisms of pain, especially the study of chronic pain, as opposed to pain in animals. The proportion is basically the same for Europe as worldwide (Figure 1A). This data supports the hypothesis of a fundamental and increasing interest in human suffering and a collective will to gain control over pain. Following the “publication share” index (Figure 1B) for publications specialized on pain as a percentage of all publications in the biomedical domain confirms the increase in the production of data on human pain. This interest may have played a driving role in studies on animal pain but this is not evidenced by the “publication share” for the field of animal pain which has shown a slight decrease rather than sustained growth.
The work reported in the literature is thus generally carried out with a view to relieving human suffering. In practice the studies are often conducted on animal models, mostly rodents or more rarely on primates. They are also conducted according to specifically controlled protocols arising directly from human clinical medicine.
Improved knowledge of the mechanisms and the control of pain is derived from various disciplines. The general approach is to combine the use of new investigative tools (brain imaging and genomics) with studies in the areas of behaviour, cognitive neuroscience, neurophysiology, neurobiochemistry and neuropharmacology. Currently new specialities are appearing and proliferating in the field of research on pain, particularly in human clinical medicine.
Over the last ten years research aimed at elucidating the mechanisms of pain has been centred round either the elementary genetic characteristics of noxious stimuli receptors (nociceptors) or the assessment of perceptive capacities and the associated levels of consciousness.
2.2. Gradual widening of the scope of studies on pain in humans
Pain is an aversive experience that comprises sensory, cognitive and emotional components. It serves as an alert warning of the presence of a threat to the physical integrity of the subject and triggers biological or behavioural mechanisms for defence or adaptation/coping (avoidance, escape). It should be noted that the lack of an ability to feel pain, a rather rare human clinical condition, is accompanied by serious pathologies. Increasing knowledge has led to a gradual widening of the whole concept of pain, both in its definition and in the range of human beings considered likely to feel it.
Figure 1A. Number of publications on pain per 5-year period in all species including man or specifically
in non-human animals without distinction of species, worldwide and at the European level:
A Medline search of articles published between 1950 and 2009 was conducted. The terms covered by the search were: pain, nociception or nociceptors, pain, alertness or awareness. The specific search on "animals" included the following English words: animals, domestic or animals, laboratory or animals, newborn or animals, poisonous or animals, suckling or animals, wild or animals, zoo or cattle or swine or fishes or sheep or ruminants or birds or poultry or swine The main disciplines included in the studies on pain are the same in France, Europe and worldwide: Neurosciences & Neurology, Biochemistry & Molecular Biology, Pharmacology & Pharmacy, Behavioural Sciences, Psychology.
Figure 1B. Percentage of all European biomedical publications dealing with pain in general or specifically animal pain over the period 1985-2009 Red circles: % of publications in the biomedical field on pain. Blue squares: % of publications specific to animal pain.
* Defined by OST (Observatoire des Sciences et Techniques : www.obs-ost.fr ), the percentage is the ratio between the number of publications from a specific actor (research institute, country, field of research…) and the number of publications in a specific database (e.g. country of the research institute, the world, or the biomedical field), multiplied by 100.
Source: MEDLINE data base in the biomedical field.
24 Expertise scientifique collective "Douleurs animales" 2.2.1. Broadening the concept of pain For years, clinicians and researchers considered pain as a sensation that either indicates trauma or tissue injury, or appears during the development of a pathological condition. This rough definition did not take into account the succession of emotions inherent in any long-lasting pain. Nor did it cover the chronic situations where, despite the absence of an obvious biological cause, the resulting pain can be just as debilitating as pain for which the bodily origin has been identified. Additionally, there is a great variability from one individual to another in the perception of pain.
A first distinction was made between acute and chronic pain. Acute pain is transitory and results from the activation of the system transmitting the noxious message. This acute feeling is an alarm signal that allows a wound or injury to be diagnosed. When this pain is prolonged and not treated quickly, it loses its biological function as a warning and becomes detrimental, giving rise to chronic pain. It affects the personal life and relationships of the individual, causing disturbances in appetite and loss of sleep. It invades the emotional world to become the dominant concern, interfering with daily life and leading to social, professional and family repercussions.
Furthermore, there are pains that cannot be readily associated with trauma or obvious injuries (projected pain that in humans is felt not at its source but in a cutaneous area, phantom pains that occur after amputations). In human clinical medicine, a nomenclature has been defined to describe the different types of pain that are not related to trauma or injuries, but to dysfunction of the nervous system.
It has been established that a person’s environment is a crucial factor in determining the person’s perception of pain. The social and cultural context modulates the way pain is felt. Thus, some ethnic and religious rituals (mutilations, for example) do not seem to have painful connotations and seldom lead to the externalisation of pain.
The threshold of pain itself is modulated by cultural factors. It has been shown that the perception of pain by an individual varies according to the level of attention to or distraction from the pain, whether or not the pain is curable, whether it is acute or chronic, reference to a similar prior experience, to the impact of the pain on lifestyle, and to the medical or the emotional environment.
All pain has an impact on affectivity. It has more or less effect according to the previous state of the individual, the intensity and duration of the pain, and can vary from transient anxiety to depression. Thus, pain can not just be taken as a simple, unequivocal reaction since its purpose is to allow the various facets of physical integrity to be maintained. Pain occupies a special place in the diversity of sensations experienced by living beings and must be understood as a feeling associated with an emotional dimension for mobilising attention.
The consideration of these facts, added to the demand from society for better pain management for patients, has resulted in the adoption of three successive pain management plans in France. This initiative, launched in 1998, will be completed in 2010 with a series of measures aimed at better pain management for hospitalised populations and among the most vulnerable patients, including children and adolescents, persons with multiple disabilities, the elderly and terminally ill. At the completion of this initiative, the medical treatment of pain, particularly chronic pain management, will have been restructured to improve the effectiveness of the whole system of patient care.
2.2.2. A recent extension to all human beings Consideration of pain in the newborn child and disabled people who are unable to express themselves verbally and, even more recently, the interest shown in pain in the foetus reflect a broadening of the range of humans recognized as being able to feel pain. The first articles published on pain in the newborn or foetus date from 1987, and those for disabled children in 1996 and 2002. It should be borne in mind that the IASP (International Association for the Study of Pain) has pointed out that an inability to communicate verbally does not mean that a person does not feel pain and does not need treatment for pain relief.