Submitted to: American Society of Animal Science Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: February 19, 2006
Publication Date: July 11, 2006
Citation: Varel, V.H., Wells, J. 2006. Influence of thymol on coliform bacteria, VFA, and methane production from pull-plug swine manure pits [abstract]. Journal of Animal Science 84(Suppl. 1):292-293. Technical Abstract: This study was conducted in swine manure pits to determine the influence of thymol addition on pathogen, odor, and methane emission. Two experiments were conducted in 2 pull-plug pits (34,000 L each) which had partially slotted floors with 6 pens (16 sows per pen) over each pit. One pit served as the control and the other pit was amended with approximately 1.5 and 3.0 g of thymol/L in experiment 1 and 2, respectively. Each experiment lasted 18 d, during which time five to six 200 ml samples were withdrawn from underneath each pen and analyzed for DM, thymol, VFA, and coliform bacteria. At the end of each experiment, 50 g samples, 6 from each pit, were placed in 200 ml serum bottles and gas volume and composition were determined periodically for 28 d. The slurry DM was not affected by thymol treatment in either experiment. Compared to the control pit, VFA production was reduced 1.28 and 1.71 mmoles/L d**-1 (65 and 100%) for thymol amendments of 1.5 and 3.0 g/L, respectively (P < 0.01). Coliform and Escherichia coli viable cells were reduced 1.55 and 1.76 log**10 CFU/g slurry for the 1.5 g of thymol/L treatment, respectively; and 2.73 and 2.94 log**10 CFU/g slurry for the 3.0 g of thymol/L treatment. Total gas production from the serum bottles was reduced 64 and 76% for thymol amendments of 1.5 and 3.0 g/L, respectively (P < 0.01); and methane production was reduced 77 and 93%, respectively (P < 0.01). These results suggest that thymol may be useful in swine production facilities equipped with slotted floor manure pits to reduce pathogens, odor, and greenhouse gas.