In Holland, measuring by Wageningen University and Research in three freewalk barn with wood chips as bedding material shows that the ammonia emission is 9.0 kilogram per cow place per year which is 31 percent less than in a conventional freestall barn with a concrete slatted floor. However: the emission of greenhouse gasses (methane) was 189.9 kilogram per cow place per year which is 34 percent more than in a conventional freestall barn.