Abstract Outdoor pig production represents a sustainable alternative for tropical regions, allowing pigs to express natural behaviors while contributing nutrients to the soil and improving its structure. However, there is limited information on how stocking density affects pigs’ behavioral patterns under outdoor systems. This study evaluated the effect of three stocking densities and a mobile shelter on excretion and rooting behavior of growing-finishing pigs in the Colombian high plain. Fourteen pigs (PIC 337; initial body weight (BW) 27 ± 1.1 kg) were assigned to three paddocks of 1000 m² each at densities of 3, 4, and 7 pigs/1000 m². Pigs were raised outdoors for 14 weeks and fed diets formulated to meet nutritional requirements (Rostagno et al., 2017). Each paddock contained a mobile shelter (2 × 2 m) equipped with roof, four wheels, a 250 L raised water tank, nipple drinker, and feeder. Shelters were moved weekly in different directions and distances. Excretion and rooting behaviors were evaluated at weeks 1, 7, and 13, when pigs averaged 27, 62, and 101 kg BW, respectively. Each evaluation consisted of two days, one before and one after shelter relocation, using direct observation from 6:00 am to 6:00 pm while recording ambient temperature hourly. Locations and times of defecation and rooting were marked manually on a 1 × 1 m paddock grid. Data were georeferenced in QGIS 2.18.17 to measure distances between activity points and the shelter and analyzed using PROC MIXED (SAS 9.4) with density as the main effect and paddock as the experimental unit. Heat maps were created in SAGA GIS 2.3.2 to contrast activity before and after shelter movement. Regardless of density or body weight, excretion and rooting events were concentrated around the shelter perimeter; pigs preferred areas between the shelter and fence for excretion, and around drinker for rooting. These patterns remained after relocation, showing a strong spatial association between shelter position and activity. The mean distance between shelter and excretion points increased (P 0.05) with BW (16.5, 24.1, 31.8 ± 1.8 m for 27, 62, and 101 kg, respectively) but decreased (P 0.05) as density increased (31.0, 28.1, 24.6 ± 3.4 m for 3, 4, and 7 pigs/m2 respectively). Rooting distances declined (P 0.05) with higher BW (11.5, 8.5, 7.5 ± 0.6 m) and density (9.4, 8.8, 5.0 ± 1.2 m). Most excretion and rooting occurred during cooler hours (6–8 am and 4–6 pm; 71–82 °F). Stocking density influenced the spatial distribution of defecation and rooting in outdoor pigs. Proper management of shelter mobility can optimize nutrient distribution and soil impact.
Sierra et al. (Wed,) studied this question.