Hoop Structures For Hog Finishing
Livestock Update, December 1997
Allen Harper, Extension Swine Specialist, Virginia Tech
Within the past two years there has been considerable interest in "hoop structures" as a lower cost facility for feeding out growing-finishing pigs. Swine researchers Jay Harmon and Mark Honeyman of Iowa State University recently reported on the performance of a hoop structure in a paper entitled "Hoop Structures - Research on Performance and Operation." The paper was based on data and observations of 3 successive groups of growing-finishing pigs (151, 150 and 163 pigs each) through an ISU swine farm hoop structure. Some key points relative to hoop structures based on the ISU report and other sources are as follows.
1. Hoop structures typically have treated lumber sidewalls up to 6 feet high with arched steel tube trusses spanning from one sidewall to the other. A polypropylene tarp covers these arched trusses such that the structure resembles a "quonset hut" type building. The ends of the structure are left partially or totally open to allow natural ventilation air to flow the length of the building. The floor is typically packed earth but often a smaller concrete pad is installed at one end on which to locate self-feeders and watering equipment.
2. A key component to the system is bedding. Enough deep bedding is kept on the floor at all times to allow for absorption of manure (urine and feces). Bedding materials vary but corn stalks, straw and wood shavings have been used. A supply of bedding would have to be kept on hand to keep the system working. Deep dry bedding in an uninsulated barn has obvious advantages during cold weather but could be more stressful during hot weather. Provisions for removal of spent bedding followed by land application would also have to be in place.
3. The ISU workers found feed conversion (lbs. of feed per lb. of pig gain) to be about 10% poorer in the hoop structure relative to records of more conventional confinement systems. This would be negative for contract growers receiving a feed efficiency bonus in their contract payments and to independent producers supplying their own feed. At current feed costs, ten percent poorer feed efficiency translates into $3.50 to $4.50 more production cost per pig.
4. The ISU workers estimated construction costs for hoop structures to be about $55 per pig capacity. This compares to about $120 per pig capacity construction cost for conventional confinement barns including a lagoon. So a key feature is substantially lower initial investment cost with the hoop structures.
5. The average labor expenditure was 0.45 hours per pig produced to operate the hoop building. Estimates for traditional confinement finishing houses range from 0.25 to 0.35 hours per pig produced, so it does appear that the hoop structures have higher operational labor requirements than traditional confinement barns.
In summary it appears that hoop structure hog finishing has potential for use under some circumstances; however, they are not likely to replace slatted floor confinement barns as the predominant hog finishing facility. The hoop buildings do have lower capital investment costs (fixed costs) than traditional buildings but this is somewhat offset by the cost of poorer feed conversion, higher labor requirements and bedding.