Page 56 - The Welfare of Cattle

MICrobIaL PathoGens 33

table 5.2 Pathogen Prevalence and Loads in Fresh animal Manure
Pathogen Prevalence and Load in animal Manure
animal type/ Escherichia Giardia Cryptosporidium
Description coli O157 Salmonella Campylobacter intestinalis parvum
Cattle
Prevalence (%) 13.2 7.7 12.8 3.6 5.4
Load (Cfu/g) 2.9 × 10 6 3.9 × 10 4 7.6 × 10 3 2.2 × 10 2 2.7 × 10 2
Pig
Prevalence (%) 11.9 7.9 13.5 2.4 13.5
Load (Cfu/g) 6.9 × 10 4 9.6 × 10 3 1.9 × 10 3 5.3 × 10 4 3.0 × 10 2
Poultry
Prevalence (%) 0 17.9 19.4 0 0
Load (Cfu/g) 0 5.0 × 10 3 4.2 × 10 3 0 0

Sheep
Prevalence (%) 20.8 8.3 20.8 20.8 29.2
Load (Cfu/g) 1.1 × 10 4 1.1 × 10 3 8.6 × 10 2 3.8 × 10 2 5.3 × 10 1
Data source: hutchison et al. (2004). note: number of manure samples for cattle, pig, poultry, and sheep were
810, 126, 67, and 24, respectively. Cfu/g is the number of colony-forming units/gram of manure.
Note: different pathogens have different effective doses required to cause disease. some need a high dose of
Cfu, some a small dose.

PathOGeN PreVaLeNCe

A pathogen’s prevalence (how often they are found) and load (how many are found in the manure
tested) in fresh manure of cattle, pig, poultry, and sheep shown in Table 5.2. Untreated manure does
represent a potential risk to animal and human health (Atwill et al., 2006; Atwill et al., 2012; Pandey
et al., 2014), and minimizing or eliminating their impact on the environment is an important goal.

PathOGeN traNSPOrt

Microbes do not have the ability to travel any significant distance on their own, and must rely
on hitching a ride on or in something that is moving such as water, dust, boots, tires, other animals,
etc. The leading method of transporting pathogenic microorganisms from manure is in ambient
water that is runoff from agricultural land (agricultural nonpoint source (NPS) pollution) (Atwill
et al., 2002; EPA, 2013; EPA, 2017a; EPA, 2017b). Both intensive and extensive animal production
systems that inadequately manage their manure, including that used as fertilizer on crop lands, often
result in an increase of microbial pathogens in ambient water (Chapin et al., 2005; Hollenbeck,
2016; Rogers and Haines, 2005).
The pathogen type and load originating from animal manure and found in cropland and soil
depends on various factors such as amount of sunlight, temperature, moisture, rainfall, pH, presence
or absence of specific soil nutrients, and the source, timing, and amount of manure applied.
Unintended runoff associated with rainfall is a major cause of contamination. The major factors
that control pathogen levels in a natural environment are time and higher temperatures and radiation
of sunlight (Baumgardner, 2012; Hipsey et al., 2008).
In North America and the European Union, there are major efforts ongoing to minimize or
eliminate the transport of manure pathogens from confined feeding operation to natural water