Swine Facilities for Production on Pasture

Raymond L. Huhnke, William G. Luce, Joseph E. Williams of the University of Oklahoma published this Fact Sheet in July 2007, offering advice on managing free-range systems for sows, boars and finishing pigs in the state.
calendar icon 15 December 2008
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Oklahoma produces only half of the pork it consumes. Economic studies have consistently indicated that swine production is a profitable enterprise in Oklahoma. Many producers have found this to be true. A completed OSU study indicates that hog production may be profitably expanded substantially beyond current levels.

Much of the present Oklahoma pork production utilizes pastures and dirt lots. Such operations use what are commonly called low investment facilities. The purpose of this fact sheet is to illustrate and discuss the use of pasture facilities for breeding, gestation, and farrowing and dirt lots for finishing.

Figure 1 presents pasture facilities suitable for the farrow- to-finish production of 80 litters annually. The breeding, gestation, and finishing facilities are planned for two groups of sows, each group farrowing 20 litters twice a year.

Figure 1. Farrow-to-finish faclities on pasture for froduction of 80 litters annually

Breeding and Gestation

For breeding and gestation on pasture, provide one acre for each 10 animals. Temporary electric fences are less expensive than woven wire fences and work well for breeding and gestation areas.

Feeding facilities are typically one of two types. Either sows are limit-fed on a concrete slab or in individual feeding stalls. While individual feeding stalls are more expensive, they offer control of the feed intake of each sow. Waterers are placed on small concrete pads.

Shelters are recommended, preferably those which can be opened during summer months and closed on all but one side during winter. Shelters can be portable or permanent and should provide 15 to 20 square feet of roof area for each animal.

Sprinklers provide relief from summer heat. For complete plans for a permanent structure providing shade, sprinkling, and concrete wallow, see Fact Sheet 3655, “Pasture Cooling for Bred Sows.”

Seperate gestation areas are suggested for gilts and sows. An electric fence easily and temporarily divides gestation space for this purpose.


Farrowing on pasture normally involves individual houses. These houses may be simple A-types without floors, or larger houses with floors and creep areas.

Houses without floors are staked down to prevent sows from moving and overturning them. Each is bedded with approximately one-third of a bale of straw during the summer and half a bale during the winter. These houses are most practical in areas with sandy soils and/or low rainfall. Figure 2 shows a low cost individual house with no floor.

Figure 2. A low-cost individual farrowing house with no floor

Larger houses with floors are also bedded, with at least 1/2 bale of straw per sow. Doors provide air movement through the house during the summer. One-half to one inch of insulation under the roof is helpful during both summer and winter. Provide 20 to 30 square feet of shade per sow.

One acre for each ten sows should be provided for pasture farrowing. It is essential that the farrowing houses be on high ground (elevated areas). One method is to terrace the farrowing area and align the houses along the ridges. Then sows and litters stay drier and they can avoid mud even during rainy periods.

Houses should be aligned with the entry doors to the south for protection from winter winds and access to summer breezes. A 2-inch x 6-inch board placed across the bottom of the door will keep pigs in the house for the first week after farrowing. The board needs to be removed when the pigs start leaving the house. Between farrowing, the houses should be moved and cleaned and the area disked.

Woven wire fences are required for farrowing. Small concrete pads are recommended for waterers and suggested under self feeders for the sows. Creep feeders are suggested for the pigs. After weaning, the pigs are grown in the farrowing pasture until the finishing lots become available.


Low investment finishing usually involves dirt lots. At least 100 square feet of lot space is provided per head. While a lot capacity of 50 head is desirable to reduce social stresses, as many as 200 head can be fed per lot. Woven wire fencing is suggested.

Figure 3. Portable shelters in a permanent lot used for finishing or gestation

Permanent or portable shelters that provide 5 to 6 square feet of roof area per head are recommended. Ideally, these shelters will be open during summer and closed on all but the south side during winter. One-half to one inch of birdproof insulation under the roof is suggested. Asphalt-impregnated insulation board and extruded foam products work well. Beaded foam products should be avoided. Figure 3 shows the type of shelters and pens useful for finishing and/or gestation.

Sprinklers can provide some relief from summer in this arrangement also. One feeder space should be provided per 4 or 5 pigs. Provide one drinking space for each 15 pigs with a minimum of 2 waterers per pen. Since mud holes form quickly in these lots, small concrete pads are recommended under waterers and feeders. No permanent vegetation is maintained in the lots. To aid in control of parasites and diseases, it is recommended that the lots be disked and graded between groups of pigs.

Boar and Gilt Pens

Replacement gilts are retained on feed for a few weeks beyond finish weight and age before entering the breeding herd. A small pen, permanently fenced with woven wire, is suggested for growing and breeding gilts.

A gilt pen and one or more boar pens are usually required. Shelters should provide 10 square feet of area per head. Concrete slabs are suggested for hand-feeding and for waterers. The pens should be arranged to provide fenceline contact between the boars and gilts.

Site and Utilities

Sandy soils are desirable to reduce the mud problems of swine production on pasture. While trees can provide shade, hogs will cause trees to die. The greater the density of hogs, the more quickly trees will be killed.

Pastures pose little pollution potential, but runoff should be controlled from dirt finishing lots. A small, shallow basin can capture and hold the lot runoff for infiltration and evaporation, if all other surface water is diverted away.

An adequate water supply and distribution system is required. Hogs require up to two gallons of water per day per 100 lbs. of live body weight. Each waterer should be supplied at a rate of one to two gallons per minute. For sprinkler cooling, a total capacity of 1/10 gallon of water per house

Permanently installed pressure water systems are recommended over gravity systems. Unless the system can be completely drained, it must be prevented from freezing during winter. Freeze-proof, manually-operated hydrants can be used to serve a small number of hogs.

Electrically heated automatic waterers are relatively expensive and require both a pressure water supply and electrical service. As an alternative, the water system can be made freeze-proof if nipple or cup waterers are connected into the main water line allowing water to be continuously circulated through all the waterers during cold weather. A valve can be used to adjust the flow rate of water with higher flow provided during cold weather. They must not contain standing water which can freeze. The flow-through watering system wastes some water during cold weather, but it costs less to install and operate than a system featuring electrically heated automatic waterers.

Other Equipment Needed

Nearly all swine systems will require a loading chute, a small tractor for moving shelters and houses, the occasional use of a disk, seeder and grading blade, and a pickup truck.

Feed Processing

On-farm feed processing is not required for swine production. Commercial rations can be purchased. Since many Oklahoma swine producers have installed on-farm processing systems, the basic requirements will be discussed here.

The layout shown in Figure 4 presents a small system using an automatic electric mill. This layout will also serve a portable grinder-mixer.

Figure 4. A small feed processing system featuring an automatic electric mill

The two most popular types of feed mills for small swine units are the portable grinder-mixer and the small automatic electric mill. Regardless of the type of mill used, a minimum of ingredient storage must be maintained.

While only one grain bin is required, two are recommended to allow two grains to be used at the same time. The minimum suggested capacity for a grain bin is 2,000 bushels, but a bin with a 3,000-bushel or larger capacity may be justified. Bins cost less on a per bushel basis as they get larger. However, two bins of 2,000-bushel size offer more flexibility than a single, 4,000-bushel bin.

Soybean meal or complete supplements may be purchased, stored, and used in either bagged or bulk forms. The lower cost and greater convenience of the bulk form should be compared with the cost of the required storage unit. Hopper-bottom tanks are normally used for bulk meal. The recommended minimum size is 12 to 15 tons. This allows capacity to receive a 10-ton load plus a carryover.

Complete supplements contain all ingredients required to produce a ration, except ground grain. If complete supplements are not used, then base mixes (complete vitamintrace mineral mixes) must either be purchased or produced. Base mixes are available in bagged form and are added to soybean meal and ground grain to produce rations. Most rations require about 50 to 60 pounds of base mix per ton.

Base mixes can be produced by mixing calcium, phosphorus, and salt sources with a vitamin-trace mineral pre-mix. If base mixes are to be produced, a premixer is required.

January 2009

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