Floor covering for an animal house for beef animals and dairy animals includes an elastomeric mat which can be fixed to a floor or floot slat by screws. Rigid strips are located at the base of the mat for securing the screws which are coverable by the mat when it is fixed to the slat. The mat is designed for cleanliness and enhanced protection and comfort for animals. A flap valve forms an openable flat valve along one longitudinal edge of the mat to close a gap between adjacent slats of a slatted floor to reduce the emission of gases and fumes emanating from a tank beneath the floor. The flap valve allows waste material to pass through the slatted floor to the tank.