Design of rooting yards for better hygiene and lower ammonia emissions within the outdoor concrete area in organic pig production

• The excretory behaviour of pigs can be steered by introducing a rooting yard.
• Hygiene studies showed advantages with a rooting yard with one high wall.
• A rooting yard with peat in the outdoor area tended to lower NH3 emissions.

Large fouled concrete areas outdoors and high nitrogen emissions are a problem in organic pig production. This is not consistent with the goal of organic farming to minimise the environmental impact of agricultural production. Introduction of a special rooting yard with rooting material in the outdoor concrete area could possibly be a way to create more activity in one part of the outdoor area, in which the pigs do not want to excrete. In the present study, the aim was to find an optimal design for such a rooting yard in the outdoor area. Four different designs of rooting yards, with varying sizes and wall heights ((LH=large (8.4 m2) with one high wall (1.0 m); LL=large (8.4 m2) with low walls (0.3 m); SH=small (5.3 m2) with one high wall (1.0 m) and SL=small (5.3 m2) with low walls (0.3 m)), were tested in parallel and compared with a reference pen (R) without a rooting yard. Peat was used as rooting material in all the outdoor rooting yards. In total, two batches, in a research facility with eight pens of 16 pigs each, were studied. Data on performance, location and activity in the pen and hygiene and ammonia emissions in the outdoor area were used for evaluation of the designs. No significant differences were seen in performance, total activity and total rooting activity between treatments. However, the pigs in the pens with rooting yards were observed rooting outdoors significantly more than those in the reference pens. Significantly better hygiene and a tendency for lower ammonia emissions from the area with rooting material were recorded in the pens with rooting yards compared with the same area in the reference treatment.It was concluded that use of a rooting yard in the outdoor area in organic pig production allows the excretory behaviour of the pigs to be steered in the desired direction, improving hygiene and the appearance of the outdoor area. A large rooting yard with one high wall was found to be the best design, giving a 14% reduction in chamber NH3 emissions (ECH) from the total outdoor area compared with the reference pen.