Overall animal welfare reviewed. Part 3: Welfare assessment based on needsand supported by expert opinion

Welfare concerns what matters to animals from their point of view. What mat ters to animals is their state of need. Satisfaction and frustration of nee ds are associated with emotional states, the subjective experience of which directly determines the welfare status of an animal. Because emotional sta tes are difficult to assess, overall welfare assessment (OWA) is best appro ached as an assessment of needs. For actual OWA a list of needs must be formulated. Different authors have f ormulated different lists. From these lists a concept need-list was constru cted. For validation the needs-based approach for OWA was discussed in inte rviews with experts (n = 21) in the field of ethology and other welfare rel ated sciences. These experts generally used mental terminology to define we lfare, but when asked to classify their definition of welfare, many preferr ed a definition in terms of measurable parameters or a combination of both mental terms (feelings) and measurables. Most experts believed that welfare can be assessed objectively and that the problem of OWA is indeed best app roached through an assessment of needs. Experts differ as to the exact comp osition of the list of needs. A list of needs is formulated which we intend to use for OWA in the case of sows.