If taken literally this freedom would imply that animals should be able to perform all behaviours in their repertoire. However, as we have seen, individual behaviours appear to have varying importance to animals. In addition, there are two categories of normal behaviour that actively contribute to, or indicate, a welfare problem:
· The first of these can be called ‘emergency’ behaviours as outlined by Marek Spinka; these include behavioural reactions to challenge such as fear or pain responses. The performance of such behaviours is considered bad for animal welfare.
· The second category is behaviours that improve the life status (welfare) of the actor at the expense of the recipient.
The most obvious of these is aggression between conspecifics. Aggressive behaviours are normal for many species and are seen in the wild. However, this normal behaviour can be seen to occur at abnormal levels in some captive conditions, and whilst the welfare of animals that win aggressive encounters could be debated, there are unambiguous costs to welfare for animals that lose.
ASSESSMENT OF NORMAL BEHAVIOUR
The assessment of animal welfare in relation to performance of normal behaviour has mostly focused on two main approaches:
1) Assessing the consequences of not being able to perform a specific behaviour.
2) Experimentally quantifying the motivational important of access to conditions which allow the performance of behaviour.
Under conditions where a behaviour cannot be performed (for instance, if it requires a particular environmental resource) animals may show no alteration to their behaviour or physiology, suggesting that the absence of the behaviour from their repertoire is trivial. Alternatively, such conditions may cause clear and substantial alterations to behaviour and physiology. Changes to behaviour can include signs of frustration or re-directed attempts to perform the behaviour (for example when piglets ‘belly-nose’ other piglets as a re-directed form of the normal behaviour they would perform on the sow to stimulate milk let-down). Abnormal behavioural responses can also include things like stereotypy or displacement activities.
A complementary approach to such assessments is the use of various behavioural choice / preference / motivational test paradigms that allow animals to behaviourally report on the strength of their preferences, or the strength of their motivational drive to perform a specific behaviour. Various such approaches exist but the common element is that experimental set-ups are used that ask the animal to report on how important behaviours are to them e.g. where animals pay a ‘cost’ to access the conditions (e.g. simply more space, or specific resources) where the behaviour can be performed, e.g. by walking a long distance, pushing a heavy door, or by forgoing some other important resource.
0 Comments