The Effects of Pen Size and Design, Bedding, Rooting Material and Ambient Factors on Pen and Pig Cleanliness and Air Quality in Fattening Pig Houses

SIMPLE SUMMARY: Inappropriate eliminating on a resting area has a negative effect on the environment, the cleanliness of pigs and pens, and can impair farm productivity. There are several factors that can affect pig eliminative behaviour. The primary aim of this survey was to investigate which factors related to the physical environment have the strongest effects on pig and pen cleanliness and ammonia concentration. Secondly, we wanted to assess the relationship between ambient temperature, air velocity and cleanliness of the pen and the pigs and ammonia concentration. Data were collected from 87 pig farms (n = 5769 pigs; n = 643 pens). The larger the eliminative area and resting area, the cleaner were the pigs. The eliminating area could have open partitions and be placed in the back of the pen. The resting area with a large amount of litter on the floor and use of straw as rooting material increased the cleanliness of this area. A more optimal pen design, such as that described in the present study, can reduce the workload for the farmers (cleaning), improve air quality, and lower the environmental footprint. ABSTRACT: There are several environmental and ambient factors that can affect pig eliminative behaviour. The aim of this survey was to investigate factors related to the physical and ambient environment that have the strongest effects on pig and pen cleanliness and ammonia concentration. Data were collected from 87 pig farms and analysed using mixed (ammonia concentration) or generalized linear (pen and pig cleanliness) model in SAS. The pen was cleaner when pen partitions were open compared to closed (p = 0.010) and increased with increasing amount of litter (p = 0.002), using straw (p = 0.002) as rooting material. Pig cleanliness was higher when pen partitions in the eliminative area were open compared to closed (p = 0.007) and increased with increasing space per pig in the resting area (p < 0.001), with decreasing temperature (p < 0.001), and lowering of air velocity (p = 0.003). Other factors that increased cleanliness was using straw as rooting material (p = 0.028) and increasing amount of litter in the resting area (p = 0.002). Ammonia concentration was reduced with increasing floor space in the eliminative area (p < 0.001) and increasing amount of litter (p = 0.006). Our results pinpoint physical and ambient conditions affecting pen and pig cleanliness and air quality.