2002 Annual Report
Research
Survival of Pathogenic Indicate Organisms in Stored Swine Manure Containing
Ground Piglet Carcasses during Cold Temperatures
Lee Johnston, Professor, Animal Science
Charles Clanton, Professor
Chuanpis Ajariyakhajorn, Research Assistant, Clinical and Population Sciences
Sagar Goyal, Professor, Veterinary Diagnostic Medicine
Funding Source
College of Agricultural, Food, and Environmental Sciences
Objective
The research objective was to determine the effects of cold temperature
(overwintering) on the survival of pathogenic indicator organisms—T1
coliphage and Salmonella anatum—in liquid manure that contained ground
piglet carcasses and was stored outdoors.
Project Description
Homogenization of farrowing house mortalities and subsequent addition
to liquid manure provides a convenient method for disposing of piglets
that die during the suckling period. However, there are concerns about
the potential for pathogens to survive in manure and ultimately be spread
on cropland with the manure. Piglets with less than 5.5-kg (12-lb) body
mass were homogenized using a commercial grinder. Homogenized piglet carcasses
were mixed thoroughly with T1 coliphage and S. anatum. The mixture of
carcass and pathogenic indicator organisms contained 3.0 x 104 PFU (plaque
forming units)/ml of coliphage after mixing. S. anatum was added to the
ground carcass mixture at 107 CFU/g of carcass (wet basis). Liquid swine
manure was collected from an anaerobic deep pit under a confinement grow-finish
room and placed in each of three 680-L (180-gal) polyethylene tanks, covered,
and placed outdoors on Jan. 19. The carcass-pathogen mixture was combined
with liquid manure in resealable polypropylene jugs so that carcass dry
matter represented 0, 2, 4 or 6% of the dry matter present in the slurry.
Tanks, jugs, and their contents were allowed to freeze and thaw according
to ambient outdoor air temperatures. Manure temperature was measured approximately
weekly and the manure/carcass/pathogen indicator organism (MCP) or manure-only
samples were collected 11 times throughout the winter. The samples were
tested for presence of T1 coliphage or Salmonella.
Results
The mean temperature of the manure/carcass/pathogen indicator organism (MCP) mixture ranged from -4.9 to 25.1oC. MCP samples collected on Day 39 at first thaw from 2, 4, and 6% treatments were 163, 336, and 410% higher (p < 0.01), respectively, in coliphage concentration than from manure-only control samples (0%). There was no difference (p > 0.10) in the concentration of coliphage among treatments on Days 95, 109, and 158. S. anatum was not detected in any control sample, but was present in 100% of MCP samples that contained homogenized carcass through Day 81. None of the collected samples contained detectable S. anatum on Days 109 or 158. These data indicate that T1 coliphage and S. anatum can survive for up to 95 and 109 days, respectively, overwintering in liquid manure containing homogenized piglet carcass. Once the manure temperatures exceeded 15oC in our experiment, the die-off rate of the organisms tested dramatically increased.