From clockwork pen scraping, to high-powered sprinklers and even “water curtains,” feedyards continue to battle dust to improve air quality and make life more comfortable for cattle and cowboys alike.
And if you're in a situation like Lubbock Cattle Feeders, there's always the issue of keeping your urban neighbors from coughing up trouble.
Located only five minutes from downtown Lubbock, TX, the 48,000-head feedyard is in the middle of a new, dust-control plan being mapped out by using a global positioning system (GPS).
Controlling feedyard dust can be like spinning your wheels. No matter what measures are taken, dry, hot, summer days can sometimes create too much dust. Cattle suffer, pen riders suffer and, if the yard is near even a small-populated area, the neighbors might cough and cuss.
But the cattle feeding industry has far from thrown up its hands and folded the cards. There are state and national studies aimed directly at feedyard dust control with hopes of settling the problem. Studies of a pilot-scale, water curtain, conducted by a partnership of commercial cattle feeders, local grassroots organizations and state agencies, are showing a 40-50% decrease in concentrations of airborne particulate matter, says Brent Auvermann, a Texas A&M University agriculture engineer who specializes in confined animal waste management.
Bobby Swift, assistant manager at Lubbock Feeders, a yard built 40 years ago, notes that the feedyard was built with pen stability and environmental controls in mind. Some pens have a 100% concrete surface. Others are 60% concrete. Even that sometimes can't hold dust to a minimum.
“We use a combination of tools to counter dust,” Swift says. “We scrape pens at least once a week and run water trucks to wet down pens and alleys. We're also in the process of installing a feedyard-wide system of water cannons designed to eventually distribute water to nearly every square foot of pen space.”
The water cannons are 1½-in. to 3-in. jumbo sprinklers that spread water over a radius of 200 to 300 ft. Their design is taken from similar sprinkler systems used for years in the desert feeding regions of California and Arizona to help cool cattle.
Using detailed, GPS-gathered maps, the system eventually will provide maximum coverage of the yard. “We want to wet down as many square feet possible for the least amount of cost,” Swift says.
The sprinkler program is being designed to meet the same specifications of the Texas Environmental Quality Incentive Program (EQIP) initiated for feedyards in 2003 by the USDA Natural Resources Conservation Service (NRCS). The program provides state or federal matching funds to assist crop and livestock producers in managing water resources and improving environmental conditions.
Watermasters Irrigation Supply is working with Lubbock Feeders and other feedyards to map out, then install the sprinkler systems.
“By designing a map using GPS-guided points, we can determine where water lines must be laid and the types of water cannons and nozzles needed to apply enough water to meet EQIP standards,” says Jeromy Gowdy, the Lubbock company's sales manager.
Greg Sokora, NRCS zone engineer in Lubbock, worked with Auvermann and the Texas Cattle Feeders Association (TCFA) last year to initiate the Texas EQIP program. Money has been allocated for feedyard sprinkler system design and installation for dust control.
Some 30 commercial feedyards inquired about the program. Seven were selected. The program is expanding in 2004 to include using EQIP funds to finance more frequent manure removal.
“We have encouraged more manure removal,” says Ben Weinheimer, TCFA regulatory manager. “If you have the opportunity to apply water, it takes much less to control dust.”
Swift says the overall sprinkler system is likely to cost about $20/head to install, and the yard's system is to be completed within four years. In the meantime, it will depend more on conventional dust control methods.
Pen maintenance is essential in the yard's program, which Swift says includes keeping the layer of dirt and manure to less than 1-in. thick. He also attempts to keep the pen moisture content in the recommended 25-40% range. Auvermann, whose feedyard waste management research spans many aspects of controlling dust and odor, says pen manure harvesting remains the No. 1 method of holding down dust.
“To control dust with water alone, a feedyard would have to apply enough water to increase the moisture content of the entire loose manure layer by 15 to 20%,” he says.
As a rule, raising the moisture content of a loose manure layer by 10% requires 5.6 gals./head/1 in. of loose manure depth, Swift adds. That's based on cattle spacing of 150-sq. ft./head. A 2-in. layer of loose manure would require 28 gals./head just to raise the moisture content from 10% to 35% (or twice as much water as for 1 in. of loose manure).
“Where water is already in short supply, manure harvesting reduces the amount of water needed to achieve dust control and increases the effectiveness of any water applied,” he says.
Costs of pen cleaning were measured in 2003 by another study conducted by Wyatte Harmon through the Texas Agricultural Experiment Station in Temple. He surveyed feedyards with feeding capacities of 800,000 head. He found scraping operating expenses were $1.33/head. The cost of manure removal averaged $1.15/head, making $2.48/head the total cost of cleaning. That increased to $3.91/head with machinery depreciation and interest.
A Curtain Of Water
Much of Auvermann's recent research involves a 270-ft.-wide, 43-ft.-tall water curtain in its third year of operation at Hereford Feedyard in Hereford, TX. The water curtain, on the downwind edge of the feedyard, is equipped with 28 nozzles spaced every 10 ft. and calibrated to distribute water droplets that Auvermann says are “just larger than a mist.”
The experiment is showing substantial results after two years. Basically, the water droplets contact the dust stirred up by cattle hooves and the wind and scrub them to the ground.
It's reduced the amount of particulate matter (PM), which is regulated by the Environmental Protection Agency (EPA). The EPA's ambient air quality standards allow a PM10 concentration of up to 150 micrograms/cu. meter within a 24-hr. period, and an annual PM average of about 50 micrograms/cu. meter.
“With the water curtain, there's been an apparent 40% decrease in PM10 (particles smaller than 10 micrometers in diameter) and a 50% decrease in total suspended particles,” Auvermann says. “Those are significant reductions from samples taken over three to four hours a day in worst-case conditions. We're trying to determine if all the reduction can be attributed to the water curtain. Some may simply be due to natural settling,” he adds.
Water is pumped at a rate of 300-320 gals./minute. Beyond 2004, studies will determine if similar positive results can be obtained using less water.
“We're also looking at a curtain upwind to assess the evaporative cooling effect of the curtain on cattle performance,” he says.
Of course, costs and water availability are the main obstacles to use of this type of program. The 270-ft. curtain cost $60,000, plus the water. Some look at increasing stocking density to help control summer dust. Swift says Lubbock Feeders increases its stocking density to about 150 sq. ft./head. That increases by about 25 sq. ft./head in cooler months.
Swift and his associates have also kicked around another control measure.
“We're looking at using spray planes to fly over the feedyard and apply water during heavy dust periods,” he says. “Anything we can do to help prevent dust problems for our employees, neighbors and cattle will be considered.”
For further information on EQIP programs that may cover feedyard dust control in your region, contact your regional USDA-NRCS office. Free or matching funds to help hold down dust would be nothing to sneeze at.
Larry Stalcup is a freelance writer based in Amarillo, TX.