7Philippea F X, Laitat M, Canart B,et al. Comparison of ammonia and greenhouse gas emissions during the fattening of pigs, kept either on fully slatted flour or on deep litter[ J]. Livestock Science, 2007,111 : 144 -152.
9Karlen G A M, Hemsworth P H,Gonyou H W,et aL The welfare of gestating sows in conventional stalls and large groups on deep litter[ J]. Applied Animal Behaviour Science,2007,105: 87 - 101.
10Jeppsson K H. Carbon dioxide emission and water evaporation from deep litter systems[J].J. Agric. Engng. Rcs. , 2000,77 (4) :429 -440.