Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: January 23, 2006
Publication Date: February 1, 2006
Citation: Miles, D.M., Owens, P.R., Rowe, D.E., Moore, P.A. 2006. Ammonia volatilization from broiler litter and cake via laboratory acid trap system [abstract]. International Poultry Scientific Forum. p. 41. Technical Abstract: Litter pH, temperature and moisture are recognized as the primary parameters influencing the mechanisms of ammonia evolution from broiler litter. Aerobic microbial activities converting nitrogen (N) compounds in the feces to gaseous ammonia usually amplify with increases in any of the above chemical or physical parameters. The objective of this study was to compare differences in ammonia volatilization between cake and litter (43% vs. 29% moisture) to assess the effects of management practices that break up the cake, leaving it in the house for the subsequent growout. Litter and intact cake samples were collected from the center of a commercial broiler house after a 42 d old flock was sold and the bedding was tilled. The litter had been used for 13 previous flocks. Preliminary tests using litter from earlier flocks indicated excellent repeatability for ammonia volatilization in the laboratory acid trap system with (1) litter only and (2) comparing litter, 21% moisture, to pad samples (the built up compacted litter underneath the friable layer, 30% moisture). In the present study using a randomized complete block design, twenty-four 50g litter samples and an equal number of 50g single-piece cake samples were placed in 1000 ml containers with inlet air supplied at 90 ml/min. The exhaust air and volatilized ammonia were trapped in a series of two flasks containing boric acid. To determine N lost, the boric acid was titrated daily with hydrochloric acid. Cumulative N losses from cake after the 21d incubation averaged 261 mg N (5.22 g N/kg) whereas litter averaged 85 mg N (1.7 g N/kg). All samples experienced moisture loss during incubation; final moisture content for litter and cake were 13% and 24.5%, respectively. During the layout between flocks, some drying of the broken up cake and litter would be expected. Litter and cake pH were similar (8.6 vs. 8.64) before incubation. At the test completion, the final litter pH was 8.26; the cake pH was 8.43. The interaction of pH and moisture loss has not yet been quantified. These results suggest that the break up of cake causing the exposure of high moisture surfaces exacerbates ammonia evolution from the litter bedding and that cake from reused litter should be removed between flocks.