Within-house spatial distribution of fecal indicator bacteria in poultry litter

Authors: WINKLER, SCOTT - Texas A&M University; COUFAL, CRAIG - Texas A&M University; Harmel, Daren; MARTIN, EMILY - Texas A&M University; Brooks, John; POPHAM, SHEENA - Texas A&M University; GENTRY, TERRY - Texas A&M University

Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/31/2017
Publication Date: 9/21/2017
Citation: Winkler, S., Coufal, C., Harmel, R.D., Martin, E., Brooks, J.P., Popham, S., Gentry, T.J. 2017. Within-house spatial distribution of fecal indicator bacteria in poultry litter. Journal of Environmental Quality. 46:1003–1009. doi:10.2134/jeq2017.05.0188.
DOI: https://doi.org/10.2134/jeq2017.05.0188

Interpretive Summary: Poultry production produces a large number of birds, but with that production comes an increased production of waste by-products, such as poultry litter. Unfortunately, in areas of the country where poultry production is increased, water quality can decrease as a result of runoff associated with land application of poultry litter. Poultry litter is a useful fertilizer and is in high demand in these parts of the country, but the levels of fecal bacteria in the litter can vary based on poultry management practices. Therefore, this study was carried out to determine the levels of poultry litter fecal bacteria in 12 broiler farms representing 3 integrators in Texas. Samples were collected throughout the houses to determine effects of location within the house and overall it was shown that levels can vary by location, but not by integrator. Overall the fecal indicator bacterial levels were below numbers previously reported in the literature and often used for water quality baselines and modeling.

Technical Abstract: Land application of poultry litter is often considered to be a major source of water pollutants in poultry-producing regions. However, reported levels of fecal indicator microorganisms in litter vary widely with considerable variation possible within houses and across farms depending upon management practices. Therefore, a study was conducted to determine the levels and distribution of indicator microorganisms within 12 broiler farms representing 3 integrators. Within each house, litter samples were collected from around the feed line, water line, north wall, cool pad end, middle, and the fan end. Litter moisture content was significantly different within the houses, with the litter being driest around the feed line (19.8%) and wettest around the water line (40.7%). Mean levels of total coliforms, E. coli, enterococci, and C. perfringens were 3.67 ± 1.50, 3.28 ± 1.05, 6.42 ± 0.66, and 3.9 5± 0.89 log10 CFU/g dry litter, respectively. Levels of total coliforms, E. coli, and C. perfringens were positively correlated with litter moisture content but enterococci levels were not. Consequently, levels of total coliforms and E. coli were highest around the water line and lowest around the feed line. Levels of enterococci were also highest around the water line but there were no significant differences in C. perfringens levels due to high variability between samples. These results indicate that areas with higher litter water content are more likely to contain higher levels of most fecal indicator microorganisms. Approaches to reduce litter water content in these areas would not only benefit the microbial quality of litter for land application but would also likely improve in-house disease control.