A Biosecure Composting System for Disposal of Cattle Carcasses and Manure Following Infectious Disease Outbreak
- Weiping Xubd,
- Tim Reutera,
- G. Douglas Inglisa,
- Francis J. Larneya,
- Trevor W. Alexandera,
- Jiewen Guanc,
- Kim Stanford *b,
- Yongping Xud and
- Tim A. McAllistera
- b Alberta Agriculture and Rural Development, Agriculture Centre, Lethbridge, Alberta T1J 4V6, Canada
d Dep. of Bioscience and Biotechnology, Dalian Univ. of Technology, Dalian 116024, China
a Agriculture and Agri-Food Canada, Lethbridge Research Centre, P.O. Box 3000, Lethbridge, Alberta T1J 4B1, Canada
c Canadian Food Inspection Agency, P.O. Box 11300, Ottawa, ON K2H 8P9 Canada
During outbreaks of infectious animal diseases, composting may be an effective method of disposing of mortalities and potentially contaminated manure. Duplicate biosecure structures containing 16 cattle (Bos taurus) mortalities (343 kg average weight) were constructed with carcasses placed on a 40-cm straw layer and overlaid with 160 cm of feedlot manure. At a depth of 80 cm (P80), compost heated rapidly, exceeding 55°C after 8 d and maintained temperatures of 55 to 65°C for > 35 d. Temperatures at 160 cm (P160) failed to exceed 55°C, but remained above 40°C for >4 mo. To investigate rates of microbial inactivation, Escherichia coli O157:H7, Campylobacter jejuni, and Newcastle disease virus (NDV) were inoculated in manure (E. coli O157:H7 and C. jejuni ≈ 108 CFU g−1; NDV, ≈ 106 EID50 g−1), embedded at P80 and P160 and retrieved at intervals during composting. Escherichia coli O157:H7 and NDV were undetectable after 7 d at both depths. The C. jejuni DNA was detected up to 84 d at P80 and >147 d at P160. To estimate degradation of recalcitrant substrates, bovine brain, hoof, and rib bones were also embedded at P80 and P160 and retrieved at intervals. Residues of soft tissues remained in carcasses after opening at 147 d and bovine tissue decomposition ranked as brain > hoof > bone. More than 90% dry matter (DM) of brain disappeared after 7 d and 80% DM of hoof decomposed after 56 d. High degradation of cattle carcasses, rapid suppression of E. coli O157:H7 and NDV and reduction in viable cell densities of >6 logs for C. jejuni demonstrates that the biosecure composting system can dispose of cattle carcasses and manure in an infectious disease outbreak.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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