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ethical guidelines
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Ethical Treatment of Animals in
Applied Animal Behaviour Research
Applied animal behaviour
studies are of fundamental importance to developing our understanding of
animals. The use of animals in such
studies does, however, raise important ethical issues. Many applied behaviour studies are
non-invasive and require simply observing animals in the environment that
they would normally be found. But,
other studies might require manipulation of the animals and/or their
environment. To help ISAE members make
what are sometimes difficult decisions about the procedures involved in their
studies, ISAE Council decided to form a Sub-Committee to write a set of
ethical guidelines. The guidelines are
written to be used by researchers, conference organisers, scientific
reviewers and the Ethics Committee to assess the acceptability of papers
submitted for presentation at its Congresses.
These guidelines should supplement the legal requirements of the
location in which the research was performed.
They should not be considered as an imposition on the scientific
freedom of individual researchers, but rather as helping to provide an
ethical framework that ISAE members may use in making decisions about the
ethical acceptability of their research. The members of the Ethics committee: Dr. Stine B. Christiansen, (Chair)
( Maria José Hötzel, (Brazil) Dr. Chris Sherwin, (Ex-officio) ( The
Guidelines are printed below. Any comments can be e-mailed to Dr. Stine B.
Christiansen (sbc@life.ku.dk). A similar version, written for applied animal behaviour
researchers in general, is published at: Sherwin, C.M.,
Christiansen, S.B., Guidelines for Ethical Treatment of Animals in Applied Animal
Behaviour and Welfare Research. Prepared by ISAE Ethics Committee (2002) 1. BACKGROUND The International Society
for Applied Ethology (ISAE) is a professional organisation of members with
primary research interests in applied studies of animal behaviour and related
disciplines. Because the work of its
members requires the use of animals, the Society has had a continuing
interest in promoting the welfare and ethical treatment of animals being used
in research. This is particularly
relevant as many ISAE members are involved directly in studying animal
welfare and ethics, or are involved in relevant committee work or legislative
procedure. Therefore, it is believed
ISAE should have a set of written guidelines to provide its members with a
basis for structured self-evaluation of the ethical nature of their work, and
to serve as inspiration when planning research involving the use of animals.
It is the intent of the ISAE Council that these guidelines will serve to
encourage appropriate research standards and may be used to assist referees
in assessing the ethical nature of abstracts submitted to ISAE congresses. ISAE
members originate from many nations with very different cultures and belief systems. In addition, they conduct a wide variety of
studies using disparate species in very different contexts. These guidelines
have been written with these great diversities in mind and, as a consequence,
are broad rather than specific. They have been written to increase awareness,
encourage individual thought and stimulate discussion of the ethical issues
surrounding applied animal behaviour research. The focus is therefore on the ethical
principles and how to handle these, rather than a list of do’s and don’ts
applicable to all scenarios. 2. INTRODUCTION The use
of animals in research and education has attracted ethical concern for many
years, most notably in toxicology and bio-medical studies. More recently,
ethical concerns have been raised over less invasive studies such as animal
behaviour research (Mench, 2000). This
raises a strong need for justification of the use of animals in behavioural
research, and some guarantee that the research is conducted in an ethically
acceptable manner (Driscoll and Bateson, 1988). Concerns about the use of animals in
research are being voiced by both the scientific and lay communities, evident
for instance by journals imposing ethical reviews of manuscripts,
requirements for funding proposals to have statements that ethical guidelines
will be adhered to, and the increasing public requirement for 'transparency'
of research. To address these concerns
before conducting behavioural research, the investigator should first assess
whether the purpose of the experiment justifies the use of animals. If the purpose is found to be justified,
the investigator should next consider what criteria must be met for the
experiment to be acceptable. This
includes an assessment of the likely pain, distress and suffering that might
be caused to the animals, and an evaluation of what level of suffering can be
considered acceptable in that particular context. The investigator should be able to explain
and justify his/her conclusions in order to demonstrate awareness of the
ethical issues and facilitate dialogue between interested parties. Finally, a critical assessment of the
experimental design will promote better quality research. 3. LEGISLATION It is
recognised that many countries already have legislation regarding the use of animals
in research. These guidelines are not
intended to replace or subvert this legislation. Many ISAE members are
directly involved in research related to animal welfare and legislation,
therefore this society is in an enviable position to be worldleaders in the
implementation of codes of good conduct relating to ethical research
involving animals. It is hoped these
guidelines will therefore serve to promote and progress animal welfare and
ethics, rather than just following 'rules' of legislation which may be
minimum standards. To ensure the highest welfare and ethical standards,
investigators should remain appraised of current relevant literature and
conduct their research according to the spirit and letter of their local
legislation as well as the spirit of the ISAE Guidelines. 4. ETHICAL STAND-POINT &
DECISION MODELS By
definition, ISAE members conduct research on animals or have a vested
interest in behavioural research.
These guidelines are therefore written with an acceptance that animals
can be ‘used’ for the betterment of human or non-human animal species. There
are different ethical stand-points whereby the use of animals in research can
be evaluated, and several models outlining the decision process relating to
the ethical use of animals in research (e.g. Bateson 1986; Porter 1992; De
Cock Buning and Theune, 1994). From a utilitarian stand-point, performing
research involving the use of animals may be justified if certain criteria
are met, such as - Using animals for scientific
purposes is only acceptable when the harm (physical or psychological) done to
animals is outweighed by the benefits of the research To
determine whether the benefits of research outweigh the costs, a cost:benefit
analysis can be performed. The ‘costs’
are assessed in terms of the harm likely to be experienced by the animals
used in the research, and the ‘benefits’ in terms of the gains to humans,
other animal species or the environment. However, the principle also implies
that the ethically acceptable option is the one that provides most benefits
and involves the least costs.
Therefore, when planning a study, the aim should not be to simply
reduce costs to a level lower than the benefits, rather, the costs should be
decreased to as low as possible (see 'Reducing the Costs') and the benefits
maximised as far as possible (see 'Increasing the Benefits'). We emphasise here that this cost:benefit
analysis should include any distress or harm caused by housing (or other experimenter
influence) prior to and subsequent to the experimental phase of the research. Applying
decision models to ones own research can be an enlightening exercise as it
can help analyse the cost:benefit of research, perhaps with a fresh, external
perspective. It is worth considering discussing
the scientific significance and ethical issues of proposed research with
colleagues in different disciplines, or lay-persons; if these people cannot
be convinced a study is worth undertaking, the investigator should look
carefully at the reasons they believe it should. Finally, any animal
investigator should never forget to ask the absolute question - "Can I justify the use of animals in
this research?” 5. REDUCING
THE COSTS A widely
accepted method for reducing the costs associated with animal research is
implementation of the Three Rs, i.e. Replacement, Reduction and Refinement
(Russell and Burch, 1959). 5.1 5.1 Replacement Replacement
means either that more sentient species should be replaced by less sentient
ones (but see the section on Refinement below for caveats about assessing
sentience), or that animals should not be used at all if the same research or
related training/education can be achieved in other ways. This may be difficult to achieve in animal
behaviour studies, although model animals, video-recordings, etc. can be used
in some circumstances. It has been
suggested (Christiansen and Sandoe,
2000) that 'replacement' in some cases can be achieved by using animals on
farms, commercial establishments, during transport or in the field, rather
than animals obtained specifically for the research. That a practice is
standard in one context, for example, the use of certain types of housing,
restraint, or management on commercial farms, does not necessarily mean that
it is ethically justifiable to replicate in the laboratory if this research
can be conducted in situ. 5.2 Reduction Reduction
means keeping the number of animals to the minimum necessary to achieve the
aims of the research, however, the investigator should not reduce the number
to so few that the results become statistically invalid. There is a tendency in research to use
fewer animals if the species is exotic or expensive to maintain, but if fewer
animals can be used for economic reasons without compromising scientific validity,
smaller numbers can also be used on ethical grounds. The number of animals used can be minimised
by several means. 5.2.1 Previous work: If similar work has been conducted previously, this can
sometimes be used to estimate the number of animals needed to produce a
definite result, or the data may sometimes be included in meta-analyses. The applicability and validity of
previously published research must be considered if it is to be used in this
way. 5.2.2. Statistical methods: The number of animals used can be reduced by good experimental
design, appropriate observations and statistical procedures that enable
several factors to be analysed with the smallest number of animals (Hunt,
1980; Still, 1982; McConway, 1992; Chiarotti and Puopolo, 2000). This will be dependent to some extent on
the behaviour being studied; if a highly variable behaviour is being
recorded, this will require a larger number of animals to reduce the variance
to an acceptable level. Tests for
statistical power can be employed to predict the smallest number of animals
that need to be used in a study in cases where variance is known or can be
predicted. (http://www.rri.sari.ac.uk/~gwh/ssize.html) 5.2.3 Epidemiological approach: Sometimes it will be possible to study the spontaneous
occurrence of behaviours as they occur on farms, zoos, in the wild, etc. This means no extra animals will be
required for the purposes of research.
Such studies can help identify which parameters are most likely
involved in a particular behaviour, and can therefore help reduce the number
of animals used in any further experimental study. 5.3 Refinement The
object of refinement is to reduce to an absolute minimum, the pain, distress
or suffering imposed on every
individual animal used. The word 'animal' (see Appendix A) is
generally taken to mean higher-order animals usually thought capable of
feeling pain or experiencing suffering in other ways. It should be noted that
Appendix A does not differentiate between the listed species in their
potential for suffering. Therefore, it
is unacceptable to substitute one species for another on the list, e.g. frogs
for rats, unless there is good knowledge that the former has a lower capacity
for suffering and this will not invalidate the aims of the research. 5.3.1
5.3.1 Choice of species: In choosing the species for a study there are several ‘-isms’ to
avoid. Sizeism should be avoided;
there is little evidence that smaller animals (at least within the
vertebrates) are any less capable of suffering. Speciesism (between non-human animals)
should also be avoided; this can occur due to the animals’ physical appearance or ecological niche of its wild
counterparts. Thus, some animals might
be incorrectly regarded as less capable of experiencing suffering because we
find their appearance or behaviour unattractive, or because in the wild they
are a pest species or live in an environment we consider undesirable, e.g.
toads, rats, squid. In addition, human
anthropocentricity means it is often very difficult for us to empathise with
the sensory perceptions of different species (e.g. the visual perturbations
caused by placing animals with ultraviolet sensitivity into environments
without ultraviolet light), or the suffering of another species (e.g. the
frustration of a hen about to lay an egg but unable to find a suitable
nest-site). The species chosen for a research programme should be the most appropriate
for the information that the investigator wishes to gain. The choice will usually require knowledge
of the problem to be investigated, the species' natural history and the
animals' previous experience. Applied
behaviour studies often aim to understand the responses of a particular
species in a particular environment.
If an inappropriate species is used, the research might therefore be
invalid requiring it to be repeated using a more appropriate species, and
thus making the initial study less
ethically acceptable. 5.3.2 Pain, suffering and distress: For any research programme that might involve pain, suffering or
distress, the investigator should assess thoroughly whether the information
gained can be justified and if non-animal alternatives (e.g. models,
video-playback) might be used. Pain,
suffering or distress should be minimised both in duration and magnitude to
the greatest possible extent, but without jeopardising the aims of the
experiment. Some species are less responsive to painful or stressful stimuli,
however, this should not necessarily be taken as indicating that these
species are more tolerant or do not experience pain and suffering. Animals might have evolved responses to
avoid showing evidence of pain or injury, presumably to avoid being targeted
by predators. In research involving surgery, pre- and postoperative care must
be implemented to reduce adverse effects both before and after the
operation. Any procedure likely to
cause pain should only be performed after adequate anaesthesia and with
appropriate analgesia, unless either of these endangers the experimental
aims. The use of neuromuscular
blocking agents alone is generally unacceptable. It should be considered that all higher-order animals (see
Appendix A) have the capacity to experience pain and are capable of
experiencing suffering of one kind or another. This will depend on many factors such as
the species, age, sex, reproductive condition, social status, individual
experience, perceptions, motivations and natural behaviour of the
animal. The possibility that
invertebrates such as spiders might experience pain or an analogous sensation
(reviewed by Sherwin, 2001) should also be considered. 5.3.3. Housing: Standard housing of animals in farms, zoos and laboratories is
often minimalist and designed primarily for the convenience of humans. This
can often result in the animals exhibiting behavioural or physiological
responses indicative of reduced welfare, although it is difficult to assess
how great this impact is. Several publications have ranked the severity of
procedures conducted on animals in research (e.g. Morton and Griffiths, 1985;
Bateson, 1991) and some include a category listing procedures/studies which
it is believed cause little or no suffering. However, housing animals under
minimalist standard conditions is itself likely to cause a degree of
suffering - even before any experimental procedures have been conducted. It might be argued therefore, that any
study which requires housing animals under standard conditions causes
suffering, even if the experimental procedure itself appears to cause
none. This means that in all
circumstances, investigators should be able to ethically justify why an
animal is being housed and/or why it is housed under particular
circumstances, even if the research does not involve a procedure that causes
overt pain or distress. To provide
suitable housing and husbandry, investigators should consider both the
quantity and quality of space they provide for their animals, and remain
appraised of current relevant literature. Again, we emphasise that welfare
implications of housing and husbandry conditions prior and subsequent to the
experimental phase should be considered in the ethical justification of a
study. 5.3.4 Identification of animals: It is often necessary to individually identify animals. There are many methods of achieving
this. Wherever possible, non-invasive
methods should be used, although these tend to be more short-term and might
require repeated re-application thus potentially causing further distress to
animals. Invasive methods that cause
minimal pain and distress (e.g. ear-tags, wing-tags) are acceptable if they
are in accordance with the aims of the study.
The size of the identification device or marking method relative to
the body-size of the animal should be considered, and the effects this might
have on behaviour or possible suffering during and subsequent to attachment/implantation. Mutilatory forms of identification (e.g.
toe-amputation), or those which injure substantial amounts of tissue should
be assumed to cause substantial acute and perhaps chronic pain, and would
therefore generally be considered unacceptable. 5.3.5 Other “standard practices” used in
husbandry: A variety of practices that are likely to cause pain, distress
or suffering are conducted routinely upon animals on farms, in laboratories,
or other commercial establishments, e.g. beak-trimming, castration, chronic
food deprivation, social isolation, etc. The fact that these practices are
performed routinely elsewhere, does not mean they should be placed above
ethical scrutiny if they are performed on animals in a research study. Indeed, many of these practices can be
considered unnecessary for animals in research, so long as their omission
does not contravene the validity of the study or its aims. 5.3.6. Presence of experimenters and handling: The presence of humans can have a considerable effect on the
behaviour of animals. This presence
may or may not cause distress to the animals, but in either case, if this
interferes with the aims of the study it reduces the validity of the research
and therefore lowers the ethical acceptability. Investigators should consider the use of
remote monitoring (e.g. video), or habituating the animals to the presence of
humans. It should also be remembered
that 'blind' studies in which the observer has no knowledge of which
treatment the animal has been subjected to, reduces the likely influence of the
observer and increases the validity of the research. The way in which animals are handled can
have a substantial effect on their behaviour and welfare in both the short
and long term. Poor handling can cause
acute responses and learned aversion to handling in the future; potentially,
this can invalidate the research.
Investigators should familiarise themselves with the appropriate
handling methods for the animals to be used. 5.3.7 Duration of the study: In applied behaviour studies, the end-point of a study is often
relatively easy to decide. For
example, a study on the behavioural responses of laying hens to a novel
housing system in the U.K. might extend for 62 weeks because this is the
average duration that hens are housed on farms (in the UK). Data beyond 62 weeks will probably be
irrelevant and therefore less ethically acceptable. On the other hand, if the work were
conducted in a country where hens were routinely housed for a longer period,
it would be less ethically acceptable to terminate the study before this
period. 5.3.8 Final disposal and euthanasia: At the end of a study, investigators should consider
alternatives to immediate euthanasia of the animals. There are sometimes good reasons for using
animals in other studies (e.g. the animals are used to being handled,
familiar with the environment or procedure), but care must be taken to ensure
the animals are not used repeatedly in stressful or painful experiments. Livestock might be placed onto farms, but
the investigator should consider the likely responses of the animals to the
change of social and physical environment, and the legal, ownership and
hygiene consequences. Similarly, some
species might be placed into private homes or sanctuaries. Field-caught animals may be placed in zoos or reserves to reduce
the need for further capture of wild animals, but again, the investigator
should consider the likely responses of the animals to the change of social
and physical environment, and the legal, ownership and hygiene consequences. Alternatively, field-caught animals may be
returned to the place of capture if their ability to survive has not been
impaired and release does not constitute a health or ecological hazard to
existing populations. The manner in which animals are euthanased is a significant
component of the ethical acceptability of a research programme. In applied ethology studies, the method of
the animals’ death will often not be under the control of the investigator,
e.g. animals on farms will usually remain on the farm and will be slaughtered
commercially. If the investigator has
control over the method of euthanasia, factors to be considered are the
likely duration of pain and distress caused by the method, and any handling
the method requires. There is evidence that some methods of
killing are less appropriate than others, despite their common use and
approval by many legislative agencies. Investigators should read Appendix B
in this regard. It should be remembered that methods of killing might be
approved by legislation because of practicality and economic issues, rather
than animal welfare. Death of the animal should be confirmed before the body
is discarded. 5.3.9 Procedures: End-Point of a Procedure: Deciding on
the end-point of a procedure, especially when this involves obvious pain,
distress or suffering, is critical for the welfare of the animal and thus the
ethical justification. Investigators should consider choosing flexible
end-points, e.g. in studies of aggressive or agonistic encounters,
behavioural indicators of an animal accepting defeat are likely to cause less
distress than encounters which have a fixed duration of interaction
arbitrarily decided upon. Death is
considered to be an unacceptable end-point. Aversive Stimuli: Animals
are sometimes deliberately exposed to aversive stimuli (e.g. electric shock,
fear-inducing stimuli, predator-prey interactions, intra-specific
competition, infanticide). If this is essential, it should be minimised in both
severity and duration in accordance with achieving the aims of the
experiment. The animals' perceptual and behavioural characteristics, age,
experience, etc. should be considered in planning the study. Investigators should monitor such studies
frequently, or preferably, constantly.
At a pre-determined point, intervention should occur; the animal
should be removed from the study and given appropriate treatment or
euthanasia. Barriers or escape routes
should be provided for the animal to avoid the aversive stimulus where this
is in accordance with achieving the aims of the experiment. Investigators should be aware of indicators
of extreme fear, e.g. learned helplessness, and that some species may
sometimes become totally unresponsive although aware and cognisant of their
surroundings (tonic immobility). Field studies should be considered as an
alternative method of investigation. Deprivation: Animals
are sometimes deprived of various resources for a variety of reasons. These
resources can be of various types, e.g. social contact, straw, perches, food,
water, comfort behaviours, suitable light.
If deprivation is essential, this should be minimised in both severity
and duration in accordance with achieving the aims of the experiment. Food is sometimes withdrawn to motivate
animals to perform a particular task, however, the use of highly attractive
foods or other rewards is often a more acceptable alternative (there is also
evidence that food deprivation can interfere with some learning tasks (e.g. Nicol
and Pope 1993; Sherwin et al., 2001)).
In general, to avoid chronic hunger, it is preferable to deprive an
animal of food for a pre-determined period of time before testing, rather
than attempting to achieve and maintain an arbitrarily specified target
bodyweight. Adverse Conditions: Studies
aimed at inducing adverse conditions in animals are sometimes conducted to
gain knowledge of applied problems, e.g. parasite loads, pesticides or
homeostatic challenges. These
procedures may cause suffering and again should be minimised in both severity
and duration in accordance with achieving the aims of the experiment.
Investigators should plan frequent or constant monitoring of such studies,
and appropriate intervention at a pre-determined end-point with appropriate
care or euthanasia of the animals.
Investigators should also consider experimental designs that allow
removal of the adverse condition rather than its addition (e.g. the use of a
novel insecticide on a population of sheep for which it is known that
ecto-parasite burdens are already high), or naturally occurring instances of
the adverse conditions. Isolation and Crowding: Many
applied behaviour studies investigate the effects of isolation or crowded
conditions that are used routinely on farms and in laboratories. It should be realised that although such
housing might be considered standard in some contexts, these systems may be
extremely stressful to animals (see 'Housing'
above). The degree of stress
experienced will be markedly influenced by the species, age, sex,
reproductive condition, social status, individual experience and natural
behaviour of the animal. These factors
should all be considered to minimise the stress likely to be experienced by
the animal. 6. INCREASING THE BENEFITS
As stated previously, the benefits of any proposed research should be made as great as possible. These can be maximised in several ways. 6.1 Achieving the aims The aims
of the research should be achievable. This
can be ensured by closely examining the aims and determining if the
appropriate animals, equipment, housing and trained personnel are all of an
adequate standard and available for the duration of the study. 6.2 Significance of the aims The aims can
be of various forms, for instance, health or welfare of humans or non-human
animals, economic gains for livestock, conservation, pest control or
fundamental knowledge. In applied
behaviour studies it is often possible to quantify and state the likely benefits
resulting from research, and therefore the significance of the aims. For example, a study on feather-pecking
might be able to state the average incidence of hens pecked, the average
number of injuries, mortality rates and the cost of increased food
consumption as the animals attempt to maintain their body temperature. Such information helps indicate the
severity and extent of the problem being addressed, and therefore the likely
significance of the findings. It may be more difficult to state the likely
benefits resulting from fundamental research. However, although it may be
hard to predict what the potential gain of the knowledge could be,
fundamental research may provide essential information and possibly even
support progress in the applied field. 6.3
6.3 Researching previous work Investigators
should thoroughly familiarise themselves with previously published relevant
literature. This avoids unnecessarily
duplicating research (assuming previous work was done correctly), although
duplication may be required in pilot studies of a novel method. It will also be possible to gauge the
variability of responses and ensure the experimental design is optimised to
achieve the aims of the study by using the least number of animals. 6.4
6.4 Reporting of the Study A
fundamental component of the ethical justification of animal behaviour
research is the communication of results.
The investigator has an ethical obligation to attempt to publish the
results as completely, widely and as accurately as possible. Doing this
decreases the probability of more animals being used in unnecessary duplicate
studies to generate similar, redundant data.
Widespread (global) communication of results is a ‘benefit’ factor in
many models of the ethical assessment of animals and thus communication of
results increases the benefits of the work. To demonstrate that an ethical
assessment has been made, the ethical justification for choice of research
and experimental design can be included. This will promote understanding and
communication concerning the ethical issues and dilemmas in research
involving animals (Christiansen and Sandoe, 2000). 7. FIELD EXPERIMENTS Investigators
conducting field experiments of applied animal behaviour should consider the
ethical issues discussed above, and in addition, the impact of their work on
other populations of animals and ecosystems.
Methods of marking, the taking of physiological samples, capture,
continuous observation, etc, might all influence an animal's ability to
survive both at the time of observation and in the future. The welfare of other animals dependent on
the subject (e.g. offspring) should also be considered. Cuthill (1991) and 8. REFERENCES Bateson, P. (1986). When to experiment on animals. New Scientist, 1496: 30-32 Bateson, P. (1991). Assessment of pain in animals. Animal Behaviour, 42: 827-839 Chiarotti,
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Animal Welfare, 3: 107-128 Driscoll, J.W. and Bateson, P. (1988). Animals
in behavioural research. Animal Behaviour, 36: 1569-1574 Hunt, P. (1980). Experimental choice. In: The
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(eds M. Stamp Dawkins and L.M.
Gosling) Academic Press, Mench, J.A. (2000). Refinement in behavioural research. In: Progress
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distress and discomfort in experimental animals and an hypothesis for
assessment. Veterinary Record, 116:
431-436 Nicol, C.J. and Pope, S.J (1993). Food deprivation during observation reduces
social learning in hens. Animal
Behaviour, 45: 193-196 Porter, D.G. (1992). Ethical scores for animal experiments. Nature, 356: 101-102 Russell, W.M.S. and Burch, R.L. (1959). The Principles of Humane Experimental
Technique. Methuen & Co Ltd., Sherwin, C.M. (2001). Can invertebrates suffer? Or how robust is
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10 (suppl) 103-118 Sherwin, C.M., Heyes, C.M., Leeb, C. and Nicol,
C.J. (2001). The effect of
demonstrator reward on social learning of key pecking by domestic hens. Proc. ISAE Still, A.W. (1982). On the number of subjects used in animal
behaviour experiments. Animal
Behaviour, 30: 873-880 APPENDIX A HIGHER-ORDER ANIMALS
Higher-order animals include all vertebrates and, of the
invertebrates, some members of the phylum Mollusca (e.g. octopus, squid) and
some members of the phylum Arthropoda (crab, lobster, crayfish). Higher-order animals are also considered to
include mammalian foetuses during the last half of pregnancy, un-hatched
young of the species stated above during the last half of their development
in the egg, and marsupial pouch young. This is because it is thought likely
that animals in these stages of development might be able to experience pain
and suffering. (This classification of
higher-order animals is adapted from New Zealand law which regulates the
scientific use of animals, Animal Welfare Act 1999). APPENDIX B
COMMENTS ON SOME COMMONLY USED METHODS
OF KILLING
ISAE
members often conduct research with farm or laboratory species. When commercially reared, these species are
often killed in great numbers and methods are used which take into account
factors such as cost, speed of throughput, and practicality; the welfare of
the animals may be given a lower priority than would be otherwise. When these species are killed after
behavioural studies, the numbers involved are usually considerably lower than
after rearing on farms or in commercial laboratories, and the animals are
often very accustomed to being handled by humans. This makes alternative methods of
euthanasia more practical and economically justifiable - or alternatively,
more time to correctly administer the method of killing. A review of the literature reveals that
some legally accepted methods of killing used commercially might have
associated with them welfare concerns that appear to be widely unknown or
perhaps ignored (see below), making these less ethically appropriate for use
on animals used in small-scale research studies. We should remember, the term
'euthanasia' generally refers to 'an easy and painless death' or 'the killing
of an animal with a minimum of physical and mental suffering, depending on
the species' (Close et al., 1996), suggesting legally accepted methods might
not always be described as 'euthanasia'.
Investigators are strongly encouraged to read Close et al., (1996) and
the AVMA Panel on Euthanasia (2001). Decapitation and cervical dislocation: There is
evidence that decapitation and cervical dislocation may not render an animal immediately unconscious. In rats, normal brain electrical activity
indicative of consciousness can persist for 30s after decapitation, and
visual responses can be evoked from hens for 30s after decapitation (Gregory
and Wotton, 1986) (see also Anon (2000) and Holson (1992)). Reptilian brain metabolism can function at
low respiration and heart rates, and Gaseous anaesthetic overdose: Exposure to
carbon dioxide is a method of killing that is widely recommended for small
farm and laboratory animals and birds, however, there are aspects of its
physical characteristics and the physiological responses induced by this gas
that raise welfare concerns. CO2 is an acidic gas that is known to
cause irritation to mucus membranes, it has a pungent odour and can cause a
profound sense of breathlessness before inducing unconsciousness in
humans. Inhalation of this gas can cause
animals to exhibit an excitation phase - this might be caused by the animal
possibly experiencing a sensation analogous to suffocation (respiratory
systems are stimulated by increasing CO2 concentrations in the
blood) - although there is debate whether the animals might already have become
unconscious at this point (Jongman et al., 2000). Pigs will voluntarily experience 72 hrs
water deprivation or 24 hrs food deprivation rather than experience a second
exposure to CO2 (Raj and Gregory, 1995; see also Jongman et al.,
2000). The degree of aversion to CO2
varies with concentration (Raj and Gregory, 1995; see also Hewett et al.,
1993; Hackbarth et al., 2000) and aversion has also been reported in several
other species, e.g. aquatic mammals and birds (Raj, 1996; Cooper et al.,
1998), thus CO2 aversion is both species- and concentration
dependent. Hypoxia or anoxia: Various
gases have been used to deplete oxygen and so cause hypoxia or anoxia. Evidence suggests that hypoxia or anoxia is
a humane way of inducing unconsciousness and death, but problems may arise
when the gas used as a substitute has aversive properties or the species of
animals to be euthanased has physiological compensatory mechanisms
(resilience or tolerance to hypoxia). Argon is
odourless, tasteless and appears to cause no aversion in pigs. A mixture of 30% CO2 in argon
causes loss of brain function in chickens, turkeys and pigs (Raj, Wotton and
Gregory, 1992; Raj & Gregory, 1994; Raj et al., 1997). Nitrogen
has also been used to induce anoxia.
Because this has a density very similar to air it must be used in a
closed container. A mixture of mostly nitrogen (>80 % by volume) and a
small proportion of argon has been recently implemented for killing broilers
under commercial conditions (Raj, A. B. M. pers. comm.). Carbon
monoxide causes rapid death through hypoxia and there is little apparent
distress caused during the induction of unconsciousness in terrestrial
species. CO must be supplied using a
commercial source of 100% because other sources usually contain additional
substances that might interfere with the effectiveness of CO hypoxia. CO is toxic to humans and therefore the
concentration both inside and outside the chamber must be monitored. Hypoxia (induced
by CO, nitrogen or argon) can cause vocalisations and convulsions after loss
of consciousness that may be aesthetically unpleasant. Due to physiological
and metabolic differences, hypoxia may not be the best killing method for
rodents, reptiles, aquatic animals and birds. General: Close et
al., (1996) and the AVMA Panel on Euthanasia (2001) list a wide variety of
methods considered to be unacceptable as methods of killing vertebrates. These included hypothermia (e.g.
ice-slurries for fish and other heterotherms), hyperthermia, drowning or
removal from water, neck crushing, nitrous oxide, cyclopropane, ether,
chloroform, sedatives (due to the large volume required), certain orally
administered agents and narcotic analgesics.
References & Further American Veterinary Medical Association (AVMA) Panel on
Euthanasia (2001). Journal of the
American Veterinary Medical Association 218: 669-696. Anon. (2000) New
Scientist, Dec 16th, p. 101 Close, B., Banister, K., Baumans., V., Bernoth, E.M., Bromage,
N., Bunyan, J., Erhardt, W., Flecknell, P., Gregory, N., Hackbarth, H.,
Morton, D. and Warwick, C.
(1996). Recommendations for
euthanasia of experimental animals.
Laboratory Animals, 30: 293-316 Cooper, J., Mason, G. and Raj, M. (1998) Determination of the aversion of
farmed mink (Mustela vision) to
carbon dioxide. Veterinary Record,
143: 359-361 Gregory, N.G. and Wotton, S.B. (1986). Effect of slaughter on the spontaneous and
evoked activity of the brain. British Poultry
Science, 27: 195-205 Gregory, N.G. and Wotton,
S.B. (1990). Comparison of neck
dislocation and percussion of the head on visual evoked responses in the
chicken's brain. Veterinary Record,
126: 570-572 Hackbarth, H., Kuppers, N. and Bohnet, W. (2000). Euthanasia of rats with carbon dioxide -
animal welfare aspects. Laboratory
Animals, 34: 91-96 Hewett, T.A., Kovacs, M.S., Artwohl, J.E. and Bennet, B.T.
(1993). A comparison of euthanasia
methods in rats using carbon-dioxide in prefilled and fixed flow-rate filled
chambers. Laboratory Animal Science,
43: 579-582 Holson RR (1992). Euthanasia by decapitation - evidence that
this technique produces prompt, painless unconsciousness in laboratory
rodents. Neurotoxicology and
Teratology 14: 253-257 Jongman, E.C., Barnett, J.L. and Hemsworth, P.H. (2000). The aversiveness of carbon dioxide stunning
in pigs and a comparison of the CO2 stunner crate vs. the
V-restrainer. Applied Animal Behaviour
Science, 67: 67-76 Raj, A. B. M. (1996). Aversive reactions of turkeys to argon,
carbon dioxide and a mixture of carbon dioxide and argon. Veterinary Record, 138: 592-593. Raj, A.B.M. and Gregory, N.G. (1993). Time to loss of somatosensory evoked
potentials and the onset of changes in the spontaneous electroencephalogram
of turkeys during gas stunning.
Veterinary Record, 133: 318-320 Raj, A. B. M. and Gregory, N. G. 1994. An evaluation of humane gas stunning
methods for turkeys. The Veterinary
Record, 135: 222-223. Raj, A.B.M. and Gregory, N.G. (1995). Welfare implications of the gas stunning of
pigs 1. Determination of aversion to
the initial inhalation of carbon dioxide or argon. Animal Welfare, 4: 273-280 Raj, A. B. M., Wotton, S. B.
and Gregory, N. G. 1992. Changes in
the somatosensory evoked potentials and spontaneous electroencephalogram of
hens during stunning with a carbon dioxide and argon mixture. British Veterinary Journal, 148: 147-156. Raj, A. B. M., Johnson, S. P., Wotton, S. B. and McInstry, J. L.
1997. The Veterinary Journal, 153: 329-340. Reilly J.S. (editor) (1993) Euthanasia of Animals Used for
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Osmond, UFAW Handbook On the Care and Management of Laboratory Animals,
Vols 1 and 2 (1999). Blackwell. Warwick, C. (1986). Euthanasia of reptiles - decapitation - an
inhumane method of slaughter for the class reptilia. Canadian Veterinary Journal, 27: 34-34 APPENDIX C FURTHER READING & INFORMATION Ethics/Codes of practice/Guidelines Anon., (2001).
Guidelines for psychologists working with animals. Quarterly Journal of Experimental
Psychology, Section B - Comparative and Physiological Psychology, 54: 81-91 Animal Behavior Society/Association for the Study of Animal
Behaviour (2001). Guidelines for the
treatment of animals in behavioural research and teaching. Animal Behaviour, 61: 271-275 Dolan, K. (1999). Ethics, Animals and Science. Blackwell Science
Ltd, Fraser, D. (1995).
Science, values and animal welfare: Exploring the 'inextricable connection'. Animal Welfare, 4: 103-117 Guide for the Care and Use of Agricultural Animals in
Agricultural Research and Teaching.
(1999) Federation of Animal Science Societies, Hart. Monamy, V. (1996). Animal
Experimentation: A Student Guide to Balancing the Issues. Orlans, F.B., Beauchamp, T.L., Dresser, R., Morton, D.B. and
Gluck, J.P. (1998). The Human Use of Animals - case studies in ethical
choice. Rowan, A.N. (1984). Of Mice, Models, and Men: a critical
evaluation of animal research. Sandøe, P. (1994). Animal Research and Ethics. In: Handbook of
Laboratory Animal Science (eds P. Svendsen and J. Hau) pp. 1-9, CRC Press
LLC, Florida, USA. Smith, J.A. and Boyd, K.M. (eds)
(1991). Lives in the Balance: The Ethics of Using Animals in Biomedical
Research. Stamp Dawkins, M. and Gosling L.M.(eds) (1991). Ethics in Research on Animal Behaviour.
Academic Press, http://www.frame-uk.demon.co.uk/guidelines.htm http://www.biotech.iastate.edu/bioethics.html http://www.maf.govt.nz/AnimalWelfare/ http://www.ethics.ubc.ca/reszources/animal/ http://www.homeoffice.gov.uk/new_indexs/index_anima.htm http://www.affa.gov.au/docs/operating_environment/armcanz/pubsinfo/mcpwa/animal_welfare.html http://www.health.gov.au/nhmrc/research/awc/code.htm http://www.adelaide.edu.au/ANZCCART/ Animal Numbers Cohen, J. (1977). Statistical
Power Analysis for the Behavioral Science. Academic Engeman, R.M.and Shumake, K. (1993). Animal welfare and the statistical
consultant. American Statistician, 47:
229-233 Festing, M.F.W. (1994). Reduction of animal use: experimental
design and quality of experiments.
Laboratory Animals, 28: 212-221 McCance, http://www.rri.sari.ac.uk/~gwh/ssize.html Pain, Suffering and Distress Flecknell, P.A. (1986). Recognition and alleviation of pain in
animals. In, Advances in Animal Welfare
Science. 1985/1986 (eds M.W.Fox, and L.D. Mickley) pp. 61-77, Martinus
Nijhoff, Gentle, M.J.
(1992). Pain
in birds. Animal Welfare, 1: 235-247 Melzack, R. and Wall, P. (1982). The
Challenge of Pain. Penguin, Rachlin, H. (1985). Pain and behavior. Behavioural Brain Sciences, 8: 43-83 Rollin, B.E. (1986). Animal pain. In, Advances
in Animal Welfare Science 1985/1986 (eds M.W.Fox, and L.D. Mickley),
Martinus Nijhoff, Stafleu, F.F., Rivas, E., Rivas, T.
Vorstenbosch, J. Heeger, F.R. and Beynen, A.C. (1992). The use of analagous reasoning for
assessing discomfort in laboratory animals.
Animal Welfare, 1: 77-84 General Animal Welfare Appleby, M.C. and Hughes, B.O. (eds)
(1997). Animal Welfare. CAB International, Broom, D.M. and Johnson, K.G. (1993). Stress
and Animal Welfare. Chapman and
Hall, Fraser, D. and Duncan, I.J.H. (1998). 'Pleasures', 'pains' and animal welfare:
toward a natural history of affect.
Animal Welfare, 7: 383-396 Gregory, N.G. (1998). Physiological mechanisms causing sickness
behaviour and suffering in diseased animals.
Animal Welfare, 7: 293-305 Mason, G. and Mendl, M. (1993). Why is there no simple way of measuring
animal welfare? Animal Welfare, 2:
301-319 Wiepkama, P.R. and Koolhaas, J.M. (1993). Stress and animal welfare. Animal Welfare, 2: 195-218
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