Pork producers in the heart of Ohio's nation-leading 30 million laying hen flock are borrowing an idea hatched in the layer industry. They built a high-rise barn for hogs with the animals on the upper level and the manure handled as a solid material on ground level.
"It's only since the mid-1960s that we decided hog manure is liquid," says Tom Menke, head of Menke Consulting Inc., Greenville, OH, an agronomic consulting company and one of the building's designers. "Before slats and pits, hog manure was always handled as a solid."
Having worked with poultry growers, Menke knew the advantages of a solid manure that can be easily loaded with a bucket tractor or skid steer and transported by semi or box spreader. Menke figures 75-80% of the poultry manure in west central Ohio is sold, brokered, auctioned or swapped for labor or equipment time. Moving manure 40-60 miles is not uncommon in the livestock dense Darke and Mercer counties, he says.
Menke says they knew that hog manure was generally richer in nutrients than poultry manure on a dry matter basis, but what could be done with the liquids? Hog manure is about 90% moisture. To handle as a dry material it needs to be close to 60%.
High-Rise Building So, about seven years ago, Menke and a poultry industry consultant, Bob Mackin, began tossing around ideas and drawing up plans for a barn to handle hog manure as a dry material.
The idea they came up with was what they call the "High-Rise Hog House." Mackin, Menke and two other partners began by putting up a 1,000-head, prototype finisher.
The first pigs were placed in the barn in July 1998. The building operated as a contract finisher for a local company that has built 30-40 new conventional finisher buildings in the last three years, some deep pit, some shallow flush, but all curtain-sided with liquid manure storage. This provided a good test for comparing the buildings' performance with hogs of similar genetics, health status and nutrition programs. Now, with four groups through the barn, the idea appears to be proving out in practice. (see Table 1).
Above the slats, the building is similar to conventional confinement finishers, with the notable exception of no curtains. But the novelty of the design resides below the slats. For starters, the pit is above ground. And before bringing in pigs, 2-3 ft. of a absorbent bedding material of wood shavings, corn fodder or wheat straw must be laid on the pit floor to absorb moisture and retain nutrients. Sliding doors on the ground floor provide tractor access for stirring or removing the final organic material.
To aid in drying the manure and to promote composting action, a patented floor aeration system was devised. PVC tubes are laid down before pouring the pit floor. About 3,200 holes are drilled into the tubes. Air is blown into the tubes from one of two, 5-hp fans, forced up through the pit floor, drying the manure.
Air pressure is strong enough to keep the holes clear of bedding and manure. Also, since the pit is above ground, the pit sidewalls are used for mounting the building's 14 ventilation fans, sized from 24 in. to 48 in. All of the building's air is pulled out of the attic through continuous baffle inlets through the slats and across the manure in the pit. This further aids in drying the manure.
"It also creates an ideal above-slat environment," says Mike Veenhuizen, a consulting agricultural engineer, Greenwood, IN. "I think having the pigs exposed to as much fresh air as possible is what we strive for in any ventilation system," says Veenhuizen, who worked with Menke on the design while he was on staff at Ohio State University.
There was concern whether there would be enough openings in the slats to pull through the volume of air needed to meet hot weather cubic feet/ minute (cfm) requirements, says Veenhuizen. But even if lying pigs cover 75% of the slats, the 2 in. of slat opening in every foot still provides enough space for air to move.
Veenhuizen also notes that the under-floor ventilation keeps slats dryer, a source of pig comfort as well as some odor and disease control.
Ohio State agricultural engineer Harold Keener has been monitoring the High-Rise building's air quality. Ammonia measurements above the slats have been between 0 to 8 ppm (parts per million) with some spikes in the winter up to 12 ppm. Readings are higher in the pits, but since ventilation is out the pit walls, this impact is negated. In a conventional deep pit finisher, readings around 20-30 ppm are commonplace.
There has been no hydrogen sulfide detected in the barn. This gas is usually generated in anaerobic storage systems. Its absence helps lessen odor and reduces human health risks.
Commercial Builder "The High-Rise has generated more interest than anything we have been associated with," says Greg LeFevre, Fort Recovery Equipment Co., Fort Recovery, OH. His company modified Menke's prototype and has built a number of commercial High-Rise buildings this past year.
"We think the concept is extremely good," he says. "Our background is in poultry so a lot of our experience building high-rise layer barns has helped us enhance the original High-Rise design."
Most of the changes in the commercial building from the prototype building were based on being able to see exactly what the dunging patterns would be. "We had four rows of posts in the prototype; in the commercial building we've only got two rows," says LeFevre. He thinks the design will keep the dunging completely away from the posts and make it easier to stir wet areas.
"We also re-spaced the pipes in the floor," says LeFevre. Instead of just equally spaced throughout the floor, there's now more air coming up where dunging occurs. They also switched from a center aisle to two outer aisles - another adjustment based on dunging patterns.
In the experimental barn, concrete was poured 13 ft. high. In the commercial barns, concrete is only poured 3 ft. high, with beefed up posts and studs from there. A year's worth of manure (and bedding material) will only reach a total of 21/2-3 ft. in depth due to the volume reduction realized from the composting action that occurs when the materials are periodically mixed. Fans can also be framed into a studded wall more easily than blocking out fan holes in a concrete wall.
Reduced gas level should also save on equipment, says LeFevre. He estimates if a typical building lasts 20 years, this will last 30.
As expected, water control is critical. Water meters keep track of water usage and wet/dry feeders or bowl waters are a must to help keep water wastage down. These water-saving methods have resulted in an estimated 75% water savings compared to standard lagoon buildings. High-Rise buildings are equipped with standard mister and soaker systems. Concerns about soaking and power washing have proven unnecessary. Only about 2 in. of the bedding pile ends up wet and it dries within a few days, says Menke.
What's the extra cost? It varies with concrete and lumber, but LeFevre says expect a 15% higher cost than a 1,000-head, tunnel-ventilated finisher with an 8 ft. deep pit. Expect to pay a little more in utilities, too. Electricity runs about $300 a month for a 1,000-head finisher.
A 4,000-head nursery has recently been constructed and populated and designs for breeding/gestation and farrowing buildings have also been produced. Prices on these designs are estimated to be closer in overall cost to their traditional counterparts, notes LeFevre.
For more information, contact Menke at (937) 447-4225 or LeFevre at (419) 375-4104.