EFFECT OF TYPE OF SLATTED FLOOR AND DEGREE OF FOULING OF SOLID FLOOR ON AMMONIA EMISSION RATES FROM FATTENING PIGGERIES

The influence on ammonia emission to the atmosphere, of five types of slatted floor and of the degree of fouling of the solid floor was inve stigated in houses for fattening pigs. In the experiment there were tw o concrete slatted floors (SI with slats 10 cm wide and 2 cm gaps; S2 with slats 7 cm wide and 1.8 cm gaps); a cast iron slatted floor (S3 w ith slats 2.5 cm wide and 1.5 cm gaps) and two floors whose metal slat s were triangular in cross section (S4 with 1 cm wide slats and 1 cm g aps; S5 was the same as S4, but partially covered over an area of 0.8 x 0.7 m with studs 5 cm high and 3.2 cm diameter, spaced at 20 cm). Th ree partially slatted compartments (all 25% slatted and 75% bare solid concrete) for 36 fattening pigs each were used. Air was drawn from ou tside through underground heat exchange tubes and entered the compartm ents via a ceiling of perforated plastic sheeting. The five types of s lats were changed around between the three compartments (three in, two out) every three weeks during two growing periods of 15 weeks each, o ne during the winter and one during the summer. Ammonia concentrations in incoming and outgoing air and ventilation rate were measured conti nuously to calculate the ammonia emission to the atmosphere. The area of the solid floor wetted with urine was assessed visually. The excret ing and lying locations of the pigs were determined from video recordi ngs.S5 showed the lowest occurrence of excretions on the solid floor. Also in S5 the lowest number of pigs were lying on the pen partition s ide (the side with naps) of the slatted floor. The ammonia emissions w ere calculated relative to S1. These were 106% for S2, 95% for S3, 73% for S4 and 64% for S5 (SED 16%). The solid floor was fouled more duri ng the summer than during the winter (P < 0.05); fouling increased tow ards the end of the growing period (P < 0.001). Opting for slatted flo ors from metal with more open space than concrete slatted floors, such as the floor with triangular section metal slats, significantly reduc es ammonia emission from the slats. Partially covering the slatted flo or with studs prevents pigs from lying in this area so that they use t his area for excretion, giving less fouling and ammonia emission from the solid floor. (C) 1997 Silsoe Research Institute.