Elimination behaviour of fattening pigs in the new housing system Wiesenschwein

Summary

The Wiesenschwein housing system is a new system for fattening pigs in Switzerland whose aim is to improve animal welfare by enabling pigs to behave naturally giving them access to an outdoor rooting area and a pasture. With that additional space, they can exercise and explore the way they would do in nature. However, with this additional outdoor area also comes along some new challenges like nutrition accumulation and losses as well as parasites burden. To minimize these issues, it is necessary to minimize the elimination on pasture. This thesis deals with free-range pig housing systems, their importance and their advantages and disadvantages. Particularly the problems of nutrient accumulation and parasites are in the focus. The main objective of the thesis was to analyse the elimination behaviour of pigs in the Wiesenschwein housing system using observations of the pigs on the rooting outdoor area and the pasture. Fattening pigs aged between 9 and 25 weeks of two different Wiesenschwein farms were observed and the location of the eliminations (urination and defecation) with the associated time were documented with a special application. In total 9 days of observation were made on which 49 outdoor bouts (i.e. a group of 35 – 40 pigs were let out to the outdoor areas for 35 - 45 min) were observed. The following data was collected: number of eliminations, preference for a location when eliminating and latency of elimination depending on feeding time and start of an outdoor bout. Elimination hotspots, as well as the correlation between number of eliminations and time and age of the animals, were analysed. It was found that the pigs in the Freilaufstufe 1 (outdoor rooting area) tended to eliminate close to walls or grids where they had contact with other animals. On pasture, the elimination frequency was lower than in the Freilaufstufe 1, and no elimination hotspots were found. Furthermore, the elimination frequency was the highest in the first 5 minutes of the outdoor bout. A higher elimination frequency was found in older animals compared to younger ones, mainly through urination. No correlations between elimination frequency and time of the day were found. Measures like preventing the pigs from accessing pasture at the beginning of the outdoor bout may be very effective for minimizing eliminations in this area.