PROBLEM TO BE SOLVED: To prevent a livestock farm from being made muddy by burying a drain-board (or drain-boards) made of thin wooden boards on the ground surface without paving.
SOLUTION: (1) The livestock farm is prevented from being made muddy by burying the drain-board 1 made of thin wooden boards 2 by bringing the long side of the cross section of the board to be vertical to prevent kneading and splashing of soil caused by hoofs of the livestock, penetrate water such as rain water into the underground and prevent the soil to be made muddy. (2) The thin wooden boards 2 used here have cross sections insufficient to bear the lord of the livestock by themselves, but they are made to have sufficient strengths by forming a composite material together with a geologic material 5 filled in spaces formed by spacers 3 of the drain board 1. The spaces of the drain board 1 are moderately arranged so as to place the hoof of the live stock on 2 to 3 thin boards. Thus, the material volume (quantity) of wood used for unit area is reduced and softness of the soil buried with the drain-board 1 is not spoiled.