Straw Systems for Feeder Pigs

John Maltman, Swine Specialist, Dugald

Raising pigs on straw has attracted interest for a variety of reasons. Primarily it offers a low cost alternative to conventional housing, however some view it as a way to provide a higher level of welfare for pigs.

In the last fifteen years, farmers have been working to perfect hoop barns for feeder pigs. This has been largely successful and it is now a matter of following an established management protocol and you will be successful. Three groups are completed annually per shelter with two groups equaling the performance of indoor raised pigs, and one group will be about 10% poorer in feed efficiency and growth due to the winter climate in Manitoba. The key elements to successfully raising feeder pigs in hoop shelters are as follows:

  1. Stocking density - recommended stocking rates are 12 square ft. (1.1 square metres) per pig. Generally 250 pigs are housed in a 30 x 100-foot (9 X 30-m) shelter and 2 shelters are filled at the same time. This simplifies marketing. Barrows usually reach market weight first, so the barrows from 2 shelters can be shipped filling a semi truck followed by the remaining gilts and barrows about 10 days later. After cleaning and re-strawing a semi truck carrying 500 weanlings will fill the two shelters again.

Group size is not limited to 250 pigs. Larger groups have been successfully raised on straw. About 7 years ago many U.S. farmers began converting curtain-sided turkey barns into finishing barns for pigs. Important to maximizing profit is matching the pen size to the supplier's group size. Mixing age groups is detrimental to growth rate and extends the shipping window. Groups of 1000 pigs of a similar age do not pose a problem provided adequate feeders, waters, and ventilation rates are provided. Reducing space per pig below the recommended 12 square feet (1.1 square metres) increases the likelihood of aggression at the feeders and waters, and increases competition for sleeping space. This results in an extended shipping period due to slower growth rates for the less aggressive pigs.

  1. Feeder space - Ten pigs per foot (30 cm) of feeder space is easy to provide and is economical. Bunker style feeders or large cube type feeders can hold 3 tonnes of feed or, with plywood extensions, up to 5 tonnes of feed per fill. Feeder design should allow pigs to stand comfortably and naturally without straining.
  2. Waterers - One four-hole waterer should be sufficient for 250 pigs. Extra bite drinkers can be added in hot summer weather to ease the pressure at the waterer. Some producers are considering adding sprinklers to help cool pigs when necessary, although this is not common.
  3. Ventilation - This is accomplished with the natural movement of air through the ends of the hoop shelter. The top metre at each end is left open, but is often equipped with baffles to close when severe wind, rain, or snow is experienced. The pigs can handle the cold, however they must be protected from drafts.

Recently, side vents are being experimented with to increase the flow of air in summer time. This is new for Manitoba, but a common construction technique in the warmer areas of the United States.

Curtained-sided barns in the U.S. use a combination of natural and power ventilation to control moisture and temperature. Most failures with hoop barns stem from efforts to close these structures too tightly to keep the pigs "warmer". Closing the tarps increases the moisture level in the shelter and causes wet straw that chills the pigs. Disease can follow.

  1. Straw Management - The composting action of the straw generates heat all year long. It is necessary to maintain a layer of straw over the main composting mass. In the winter, pigs burrow under the dry straw down to the heating area to stay warm. In the summer, the pigs will try to get wet and will lie on top of the dry insulating layer of straw. Putting too much straw in the shelter is expensive, so try to avoid this. Not enough straw makes the pigs uncomfortable, so ensure enough is given to make the pigs feel comfortable.

Twelve to fifteen large (700 kg) round or square bales can initially be stacked in the shelter since the small pigs don't need the space. As the pigs grow and need more straw, there is ready access regardless of the weather.

These are the basic principles of raising pigs on straw. Producers are developing new ways to make this approach less physically demanding. Skid steer vehicles can easily move straw on farms where a large number of shelters are used. Auto sorters are beginning to be experimented with on the farms with ten or more shelters. These changes will reduce the work of sorting and loading market weight pigs. Each new advance usually adds cost. It is important to remember these low cost structures can quickly become expensive if too much equipment is added. They function on a very simple principle of natural ventilation with straw as a moderator of cold weather. Cost ranges from $60/pig place for a simple set up to $100/pig place for more equipped sites.

Keep the costs in sight. If they rise to the point where they are near a conventional barn then consider building a standard type of feeder barn.