INFLUENCE OF ELECTROLYTE BALANCE AND ACIDIFYING CALCIUM SALTS IN THE DIET OF GROWING-FINISHING PIGS ON URINARY PH, SLURRY PH AND AMMONIA VOLATILIZATION FROM SLURRY

This study investigated the effects of dietary electrolyte balance (dE B = Na + K-Cl meq/kg DM) and acidifying Ca-salts on slurry pH and ammo nia emission from slurry of growing-finishing pigs. Ninety gilts of ab out 40 kg BW were randomly allotted to 18 diets in five replicates. Tw o basal diets were used. Diet A had a high dEB (320 meq/kg DM) and die t B a low dEB (100 meq/kg DM). Each diet was supplemented with one of the four Ca-salts (CaCO3, CaSO4, Ca-benzoate or CaCl2) to increase Ca content by 3 or 6 g per kg of diet. Faeces and urine were collected se parately in metabolism cages and mixed as slurry. In a subsample of th is slurry, pH and ammonia emissions were measured in a laboratory syst em. The low dEB diet produced urine and slurry with lower pH, and less ammonia was emitted from the slurry. Replacing dietary CaCO3 by CaCl2 , CaSO4 and Ca-benzoate reduced ammonia emission by 30, 33 and 54%, re spectively. It is concluded that ammonia emission can be reduced by de creasing dEB level and adding CaSO4 and CaCl2 to the diet instead of C aCO3. The most profound effect is achieved when CaCO3 is replaced by C a-benzoate. (C) 1998 Elsevier Science B.V.