Spatial Distribution of Bedding Attributes in an Open Compost-Bedded Pack Barn System with Positive Pressure Ventilation in Brazilian Winter Conditions

SIMPLE SUMMARY: The use of compost-bedded pack barn (CBP) systems for dairy cattle housing can improve animal welfare and herd productivity, but it is necessary that the bedding is properly managed. Therefore, evaluating the bedding quality conditions in this confinement system is paramount, as the results obtained can be used as a basis for adequate management. In this study, bedding attributes were mapped in a CBP with positive pressure ventilation. From the mapping, it was possible to identify areas with unsuitable conditions for the staying of the cows (surface) and for the composting process (at 0.2 m depth). The results achieved in this study can be used to guide decision-making processes regarding bedding management in this housing system. ABSTRACT: The objective of this study was to characterize the dependence and spatial distribution of bedding attributes in an open compost-bedded pack barn (CBP) system with positive pressure ventilation during the winter period in Brazil. The study was conducted in July 2021, in the Zona da Mata region, Minas Gerais, Brazil. The bedding area (shavings and wood sawdust) was divided into a mesh with 44 equidistant points. At each point, the bedding temperature at the surface (t(B-sur)) and at a depth of 0.2 m (t(B-20)) and the air velocity at bedding level (v(air,B)) were measured, and bedding samples were collected. The bedding samples were used to determine the moisture level and pH at the surface (M(B-sur) e pH(B-sur)) and at a depth of 0.2 m (M(B-20) and pH(B-20)). The spatial behavior of the variables was evaluated using geostatistics techniques. For all variables, the occurrence of strong spatial dependence was verified. Through the maps, it was observed that t(B-sur), t(B-20), M(B-sur), M(B-20), and v(air,B) showed high spatial variability, whereas pH(B-sur) and pH(B-20) demonstrated low variation. On the surface, values of t(B-sur) < 20 °C and M(B-sur) > 60% were observed. At the subsurface, there was a predominance of t(B-20) < 40 °C, M(B-20) > 60%, and pH > 9, which are indications of low bedding composting activity.