Review of the assessment of animal welfare with special emphasis on the "Welfare Quality® animal welfare assessment protocol for growing pigs"

This paper discusses the arising need for an objective, but feasible, reliable and valid method for assessing animal welfare on farms. Animal welfare has become especially important since the industrialisation of animal housing after the Second World War and as public awareness and concern has increased. Simultaneously, alienation of the public from agriculture has taken place, as the population has moved increasingly from rural areas to towns. This has led to a very emotional discussion concerning the welfare of farmed animals, and thus a need for not only a clear definition but also a way of objectively measuring it has arisen. It is probably best defined as a total of the different conceptions health, natural behaviour and positive affective state. In the last few years, different methods for an objective assessment have been developed; however, all of them still face great challenges in their practical implementation and acceptance. The most promising method is probably the Welfare Quality (R) (WQ) approach, especially as it concentrates on animal-based parameters. The development of the WQ protocols emphasised not only the different conceptions of animal welfare but also especially the feasibility, reliability and validity of the parameters to be included. One of the main challenges of these protocols remains, however, the final aggregation of the results to a welfare score. Furthermore, a thorough cost-benefit analysis has not been carried out so far. Even more importantly, only a few studies have addressed the general reliability and validity of the complete protocols, and those studies that have addressed these issues have also revealed challenges concerning the interobserver and test-retest reliability of some of the included parameters. As an example, this is discussed in detail for the "Welfare Quality (R) animal welfare assessment protocol for growing pigs". In conclusion, the WQ approach can be seen as promising, but it has also revealed that there are still a considerable number of challenges that need to be addressed in further studies on the WQ protocols in order to achieve constant improvement. These challenges should be borne in mind in the application of these protocols, which should not be simply referred to as a gold standard.