The objective of this study was to identify the effect of silage density on quality and efficiency of crop preservation. Feed quality is reduced in loosely packed silos because of decreased dry mater and nutrient losses from aerobic deterioration.  Adequate packing in the silo to attain the minimum recommended density of dry matter is a challenge. This study estimates how packing tractor weight, silage dry matter, rate of fill and blade layer work together to effect dry matter density. Increasing packing tractor weight, number of packing tractors and reducing layer thickness result in increased dry matter density. High density in horizontal silos minimises losses and reduces storage costs. High density reduces the porosity of the crop and a higher density increases the storage capacity of the silo. Density increased from top to bottom of horizontal silos and significant difference in silage densities across the face of the pile are noted. Lower densities are consistently registered along silo walls, therefore extra attention should be paid to packing along the silo walls. Using a heavy tractor with narrow tyres could be a way to reduce feed losses. Only an experienced operator should be employed to pack along a wall with a heavy tractor. Silage should not be packed too high or too steep, as that could  increase the likelihood of rolling the packing tractor over. Silage density in horizontal silo is most strongly influenced by packing layer thickness (L), tractor weight (m_v), packing time per ton as-fed (t_u ) and dry matter content (DM). Muck and Holmes (2000) proposed that the relationship between these four factors forms the packing factor (PF). Silage density is moreover influenced by delivery rate, moisture content, dimensions of the horizontal silo and particle length.