Bewertung von Tierwohlindikatoren für Mastschweine | Assessment of animal welfare measures for fattening pigs

The welfare of farm animals is a subject of controversial debate in the economy, politics, society and science. Methods for the assessment of animal welfare are an important component in objectifying the discussion. With the publication „Animal Welfare Indicators: Practical Guide – Pigs“ the Association for Technology and Structures in Agriculture [Kuratorium für Technik und Bauwesen in der Landwirtschaft e.V. (KTBL)] has made a proposal for assessing the welfare of sows, suckling pigs, weaning pigs, and fattening pigs. With respect to the assessment of the welfare of fattening pigs, the guide includes a total of 13 indicators as well as methodological recommendations for their assessment. The aim of this thesis is to investigate the validity, reliability, and feasibility of these indicators as well as the recommendations contained in the first edition of the guide, which was published in 2016. The second, updated edition of the guide, which has been available since 2020, has no relevance for the present thesis. Regarding reliability, the two dimensions inter- and intra-observer reliability were examined. To evaluate the inter-observer reliability, three different evaluators recorded the animal-related indicators of the KTBL guide for the same fattening pigs on one farm. Eight repetitions of this procedure were carried out over a four-week period. To assess intra-observer reliability, the same three evaluators assessed the welfare of the farm's fattening pigs according to the KTBL animal welfare indicators a total of eight times at approximately two-hour intervals on two consecutive days. The inter- and intra-observer reliability of the indicators was calculated from the results using intraclass correlation coefficients. The main result is that the KTBL indicators investigated differ greatly in this respect. The inter-observer reliability of the indicators ranges from very good (indicators skin lesions, ear lesions and tail length) to medium (indicators faecal soiling and tail lesions) to poor (indicator lameness). In terms of intra-observer reliability, the indicators receive a very good (indicators ear lesions and faecal soiling), good (indicators skin lesions, tail length and lameness) or medium (indicator tail lesions) assessment. As a dimension of validity, the sample validity of the indicators lameness, runts, ear lesions, skin lesions, tail lesions and faecal soiling was examined. The KTBL guide recommends a sample evaluation for these indicators instead of a full census, which means the evaluation of all fattening pigs in a herd. A case study in which the five different sampling strategies "simple random sampling", "stratified random sampling", "clustered sampling", "stratified clustered sampling" and "sampling according to the recommendations in the KTBL guide" were tested, each with 100,000 replicates, comes to the following conclusion: The prevalence of the indicators after sampling deviates in some repetitions considerably from the prevalence after a full census. In terms of accuracy, the five strategies differ only slightly. With respect to feasibility and bias, the five strategies vary more noticea-bly. The two strategies clustered sampling and stratified clustered sampling represent a promising alternative to sampling according to the recommendations of the KTBL guide due to a similar validity but slightly higher feasibility. The acceptance and feasibility of the KTBL guide was assessed by 40 fattening pig farmers in interviews. Apart from the indicators faecal soiling and tail length, all KTBL indicators were accepted for the animal welfare assessment of fattening pigs by most farmers interviewed. The practical recordability of the indicators in the barn is rated as simple or very simple by more than 50% of the farmers. The ratio of the time required to carry out the animal welfare assessment in accordance with the KTBL guide and the benefit derived from it was rated on average as moderate. Possibilities for improvement are analogue or digital tools for conducting the animal welfare assessment as efficiently as possible, as well as a standardized procedure for evaluating the data including an aggregated result as key figure, which reflects the current status quo of the animal welfare level on the farm and can be compared with former results. In addition, a revision of the recommendations on sample size and number of scores for the indicators lameness, ear lesions and tail lesions was suggested. The studies and results described represent a first contribution to the scientific investigation of the part of the KTBL publication „Animal Welfare Indicators: Practical Guide – Pigs“ rele-vant to the animal welfare assessment of fattening pigs. Further studies are necessary for a holistic evaluation of the reliability, feasibility and validity of the indicators as well as recommendations for their recording. Based on the results obtained so far, the KTBL guide is well suited for assessing the welfare of fattening pigs with the aim of sensitizing livestock owners or as a tool for fulfilling the onfarm self-assessment required by the Animal Welfare Act in Germany. The use of the tool for the analysis of weaknesses on the farm is possible with exceptions and limitations. An application in official inspections, in certifications or for benchmarking between farms cannot be recommended. Ultimately, the latest scientific knowledge on positive animal welfare and corresponding indicators should be integrated into the KTBL publication „Animal Welfare Indicators: Practical Guide – Pigs“.

2024-08-12