Characteristics and Effects of
Cattle Feedlot Runoff
MARION R. SCALF, Research Sanitary Engineer
WILLIAM R. DUFFER, Research Aquatic Biologist
R. DOUGLAS KREIS, Research Aquatic Biologist
Robert S. Kerr, Water Research Center
Federal Water Quality Administration
U. S. Department of the Interior
Ada, Oklahoma
INTRODUCTION
Much publicity in the last few years has followed the tremendous growth of
the animal feeding industry, especially beef cattle feeding. Modernization of animal
production methods to satisfy the public demand for more and better quality meat
has resulted in many large concentrated feeding operations. Cattle feedlot capacity in
the United States has been increasing at about 10 per cent annually in recent years,
and in the plains area of Texas, Oklahoma, Colorado, Nebraska, and Kansas the
increase has been about 30 per cent annually. Essentially, all of this growth has been
in the form of large scale feedlots of 5,000 to 100,000 head capacity. As with the
concentration of people, the concentration of thousands of animals in a small area
produces massive environmental problems.
During a beef animal's stay of 120 to 150 days in a feedlot, it will produce over
a half tone of manure on a dry weight basis, usually deposited on less than 200 sq ft
of surface. The natural assimilative capacity of the soil is overtaxed, resulting in an
enormous waste disposal problem for the feedlot operator. A major water pollution
problem develops when rainfall runoff comes in contact with the manure and carries
high concentrations of oxygen demanding materials, solids, nutrients, and disease
organisms into surface waters or leachate carries pollutants into the groundwater.
Rainfall runoff may contain pollutant concentrations 10 to 100 times those of raw
municipal sewage; and uncontrolled access to streams can result in oxygen depletion,
fish kills, and other long term, undesirable ecological conditions for many miles
downstream.
Because feedlot runoff is intermittent, it has been difficult to determine the
quantity and quality and the effect on receiving streams and/or reservoirs. This study
was designed to measure the quantity of rainfall runoff and its pollutional characteristics from a commercial feedlot and evaluate the effect of this wastewater on small
impoundments.
PROJECT DESCRIPTION
Location of the project is an operating 12,000 head beef cattle feedlot shown
in Figure 1. The feedlot consists of 96 feed pens, each measuring 125 ft wide by 100
ft deep and containing 125 cattle. As shown in Figure 2, all of the feed pens are
sloped at about 3 per cent toward alleyways which act as drainageways to the runoff
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