By: Stephen B. Blezinger
Ph.D., PAS

Part 3

In Parts 1 and 2 of this series, we began an in-depth look at why water is so important and what contributes to water quality. We began taking a look at measures of water quality, most of which can be considered chemically related. The items we discussed such as total dissolved solids, nitrates, salinity, mineral content and so on all contribute to water quality and excessive levels of any of these can affect intake and animal health, well-being and performance. In this section we will discuss water components that are more biological in nature: bacteria, most importantly pathogenic bacteria that can create health hazards for animals and humans. Other contamination problems include algae and presence of disease organisms.

Most commonly, bacterial counts are affected by manure contamination in water, particularly stock ponds that are easily accessible to cattle. Feces and urine are common contaminants in cattle drinking water, particularly when the primary source of water is a pond where cattle may spend a good deal of time loitering. Manure is carried into drinking water on the cattle's hooves and is deposited directly when the animals defecate or urinate into the water supply. Unfortunately it is not uncommon, especially in warm weather to see cattle standing in a stock pond and having one animal drinking while another is defecating or urinating into this same water source only a few feet away. Livestock drinking water that is contaminated with manure can and does become a concentration for bacterial growth, which can, and does obviously, cause disease. This problem increases during very dry periods as water levels drop and the concentrations of particulate matter and the various micro-organisms increase. High levels of bacteria have been found in cattle watering ponds where they may contribute to outbreaks of coliform related illnesses caused by E. coli and Salmonella species. These can lead to mastitis, urinary tract infections, diarrhea and numerous other problematic and lethal infections. Contamination of cattle drinking water by feces can feed algae blooms through a process known as nutrient loading, or eutrophication. Blue-green algae are common contaminants in standing water. When ponds become overgrown with algae, cattle will avoid drinking from them in favor of other water sources if available. If not, they will decrease their overall water intake, which results in decreased performance. In addition to blue-green algae, other water-borne microbes can negatively impact animal health. For instance, Leptospirosis, which causes reproductive loss in cows, is spread by a microorganism found in water contaminated by urine. The soil-borne microbe believed to be primarily responsible for foot rot (F. necrophorum) can also be spread by consumption of contaminated water.

Greater Implications – Not Just Livestock

Spiehs and Goyal (2007, http://www.extension.umn.edu/distribution/livestocksystems/components/8544.pdf) discussed the implications that pathogenic bacteria contamination can have on human drinking water sources. Pathogens can be transmitted to humans directly through contact with animals and animal waste or indirectly through contaminated water or food. Examples of human illness and death caused by exposure to livestock manure can be related to E. coli 0157:H7, Campylobacter, Leptospira and Chryptosporidia. Water can become contaminated by runoff either from livestock facilities or from excessive land application of manure. Pathogens can contaminate food products during meat and milk processing. Simply coming into contact with a pathogenic organism does not necessary mean that an individual will become sick. Some pathogens are highly virulent, meaning that exposure to even a few microorganisms can result in sick¬ness. Others are less virulent. Healthy people exposed to low doses of less virulent pathogens likely will not become ill. However, elderly, young, or other susceptible individuals (those with a compromised immune system) may become sick when exposed to even low levels of less virulent pathogens. Because it is impossible to know who will come into contact with pathogens from a live¬stock production area, it is a good management practice to reduce all potential exposures by controlling pathogens in livestock systems.

As mentioned previously, some of the most commonly recognized pathogens from livestock include bacteria such as Shiga-toxin producing Escherichia coli (E. coli), Salmonella, Campylobacter, and Yersinia. Most bacteria can survive and even multiply in environments outside of the animal such as livestock manure. These bacteria can cause fever, diarrhea, vomiting, nausea, and abdominal pain in humans who are directly or indirectly exposed to contaminated manure. This exposure can result from drinking contaminated water or eating foods (fruits, vegetables and meats) that have not been washed/cleaned properly (most foods go through multiple “cleanings” as they travel from point of production to the plate) and/or have not been cooked properly.

Organisms of concern are not just bacteria. Protozoa from livestock waste can also cause disease in ex¬posed humans. Giardia and Cryptosporidia are considered to be the two most important waterborne protozoa of live¬stock origin. These protozoa are important because they are present in animal manure and are not easily destroyed except by filtration.

A great deal of work has been done in the area of food safety to minimize exposure but problems still take place. The consumer has to understand that these organisms are everywhere, not just in manure. As such, total elimination is virtually impossible so exposure preventative steps must be taken at the producer, processing and preparation levels but also by the consumer on foods prepared at home. New technologies and products are identified every day that help reduce the potential of exposure.

Although not as common as bacteria and protozoa, viruses can also be present in animal manure. Rotavirus is the most commonly recognized pathogenic virus in animal manure. Viruses cannot multiply outside of the animal, but are ca-pable of surviving for long periods of time in the environ-ment depending on environmental conditions. One study found that rotavirus could survive in a manure storage facility for more than six months (Pesaro, et al, 1995).

Reducing Micro-organism Contamination in the Animal and Water supplies

What can producers do to reduce potential contamination of surrounding surface and ground water from their live¬stock or poultry operations? There are three basic points in the manure management cycle as it relates to water contamination where producers can imple¬ment practices to reduce pathogens: (1) in the animal, (2) during manure collection and storage, and (3) during land application of manure. A good pathogen reduction pro¬gram will include Best Management Practices (BMP) at each of these three points. Let's take a close look at numbers 1 and 2.

1)      Pathogen reduction in the animal - The more pathogens present in the animal, the greater the risk that food or water will be contaminated by the manure from the infected animal. Sick or stressed ani¬mals are more likely to shed pathogens in their manure than healthy, comfortable animals. Water runoff from pens or pastures where sick cattle are kept and treated should be carefully managed and not allowed into drinking water sources. Some animals appear healthy but are “carriers,” meaning they have previously been exposed to disease-causing microorganisms and can shed pathogens in their manure when they feel stressed or uncomfortable. In addition, some animals shed pathogens even when they appear perfectly healthy. Therefore, sim¬ple management practices such as vaccinations, adequate access to feed and water, appropriate space allowance, temperature and ventilation control, on-farm sanitation and biosecurity measures and good animal husbandry practices are good first steps for producers to reduce pathogens in their water quality and manure management sys-tems. A great deal of information is available on-line and from your local university or extension office on effective protocols.

Obviously breeding cattle are generally raised in pasture systems while feedlot cattle are grown and finished in confinement facilities. Questions have been raised as to how this influences the prevalence of patho¬gens in livestock waste and exposure to water sources? Cattle raised on pasture does not appear to affect the strains of pathogenic E. coli most commonly asso¬ciated with severe food borne illness in humans, including E. coli O157:H7. Research has shown that there is also no difference in the prevalence of E. coli O157:H7 in manure from cattle raised on pasture compared to those raised in confinement. A primary difference exists in how runoff water is managed. Feedlots are required to control runoff water and not allow ready transference to other groundwater sources including streams and rivers.

The control of flies, birds and rodents in livestock operations may also help re¬duce the spread and subsequent infection of other animals with pathogenic bacteria. Flies and bird fecal samples from cattle farms in the U.S. have tested positive for E. coli O157 (Hancock, et al, 1998). Numerous studies indicate that Salmonella can survive for at least several days, and for as long as nine months, on insects, rodents, and surfaces of building materials such as wood, concrete, iron, steel, and brick. Salmonella can survive in rodent feces for up to five months, which emphasizes the need for adequate rodent control, and frequent and thorough cleaning of animal facilities.

Producers may or may not have a choice in the type of housing facility that is available for their operation. However, implementation of BMPs that are consistent with good animal husbandry to reduce animal stress is an easy first step for reducing pathogens in any livestock operation and subsequent contamination of water supplies. It is likely that the small economic expense of implementing these BMPs will be recovered with in¬creased animal performance.

2)      Control of runoff into water sources. Controlling runoff into drinking water sources is a challenge. In most cases it is impossible to limit access to stock ponds or streams as sources of livestock drinking water and control potential manure contamination. However, in some circumstances, access can be limited to some supplies while providing access to others. One method of reducing runoff to water supplies includes use of vegetative filter strips. This can work in some specific situations. Runoff and erosion from open feedlots and fields where manure has been applied can be routed through grass filter strips to remove sediment, nutrients, and bacte¬ria. The effectiveness of vegetative filters at removing pol-lutants and microorganisms depends upon site character¬istics such as slope, amount of runoff, type of wastes, and presence or absence of concentrated flows. Time of year is also important. The vegetative filter strips will be less effective during springtime snowmelt in more northern areas or in periods of high rainfall in the south when the amount of runoff is high, when the filter strips may still be frozen or grasses are not actively growing. One study has shown that grass filter strips (15 to 30 feet in length) remove 75 to 91 percent of fecal coliforms and 68 to 74 percent of fe¬cal streptococci from runoff obtained from plots where manure was applied for fertilizer. Cattle confinement areas should have a 66 to 99 foot (this can vary depending on state guidelines) vegetative filter strip between animals and surface water in order to minimize contamination.

Some livestock operations (such as poultry farms, particularly broiler or growing turkey operations) need to stockpile manure before land application. If manure must be stockpiled, producers should follow all regulations set by the state regulatory body. Many states require that stockpiles be located, constructed, and operated so that manure-contaminated runoff from the site does not discharge into waters of the state. In some cases permanent stockpiles must be placed on a concrete pad or clay base and have at least two feet of separa¬tion distance between the base of the stockpile and the seasonal high-water table. Catch basins can be used to prevent runoff from permanently stockpiled manure from reaching surface water.

Another option is the use of catch basins. Catch basins can be used to contain manure-contaminated water from an open lot. The water collected in catch basins can be land-applied or further treated by running through vegetative filter strips.

Berms and ditches can be used to divert up-slope runoff and rain water from build¬ings away from open lots or other areas where manure may accumulate. Preventing this excess water from enter¬ing the lot or manure stockpile area will not only reduce pollution potential, but will also help keep these areas drier. Drier facilities can improve animal health, which in turn lowers pathogen levels in manure.

Although not practical in many instances, fencing livestock away from open water is an effective method of improving water quality. Keeping animals away from open water will prevent urination and defecation in the stream which can lead to bacterial pollution. Animal health may also be improved through reduced exposure to water-transmitted diseases and foot rot. This requires the installation of alternative livestock water systems which replace direct, uncontrolled livestock access to streams, ponds, and lakes.

Best management practices to control runoff from livestock operations will not eliminate or reduce pathogens on a live¬stock operation. However, implementation of these BMPs will prevent pathogens from leaving the livestock opera¬tion and potentially contaminating food or water supplies.


The quantity and quality of drinking water provided to beef cattle has a undeniably significant impact on animal life, health and performance. Water is the number one nutrient and cannot be taken for granted. Taking proper management steps to provide clean, high quality water is a basic foundation component to a cattle management operation.

Dr. Steve Blezinger is a nutritional and management consultant with an office in Sulphur Springs, TX. He can be reached by phone at (903) 352-3475 or by e-mail at [email protected] You can also follow us on Facebook at www.facebook/Reveille Livestock Concepts.

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