In the last few years, wean-to-finish buildings have been sprouting up throughout the Midwest at a record pace.

Almost as fast as those buildings were put in production, some producers discovered that raising pigs from 10 lb. to 250 lb. in one big room was not such an easy task.

Many have learned that the younger pigs take a higher degree of management and the proper equipment.

Bob Johnson recognized that wean-to-finish buildings have an inherent flaw --they give 10-lb. pigs more space than they really need. So he designed facilities to double-stock pens and make use of that extra space.

Building In Changes Johnson and his two partners, sister Peggy Pate and brother-in-law Steve Pate, DVM, began planning their Johnson Farms' wean-to-finish units last winter. The three-site production system is doubling in size from 600 to 1,200 sows.

Their plan is to match the wean-to-finish production schedule with the existing operation which includes nine nursery rooms and separate grower and finishing facilities on another site. Half the weaned pig production will go through the existing production setup, says Johnson, half through the new, wean-to-finish system.

So far the wean-to-finish complex is not yet finished. The first group to go through it are gilts being grown out in four rooms in one building. Early weaned Newsham Hybrid gilts will be used for the expansion. Steve Pate says out of the first batch of about 600 head, only 1% has died.

Johnson speculates work on the concrete and building will resume in the spring. He expects full occupancy by early fall.

Planning Strategies Johnson, with a degree in agricultural engineering, and Pate, DeKalb, IL, outlined their plans and strategies for developing their wean-to-finish system featuring a unique approach to double filling pens.

Johnson says while some operations have struggled with manpower challenges of raising young pigs in a finishing environment, he is confident they have a top management team in place. Rather, his concern has been with some facets of the building concept.

'We originally drew up some ideas for six, 1,000-head buildings that would accommodate our goal of weaning about 480 pigs a week,' says Johnson. 'It would have been a fairly typical arrangement where we would stock a building in two weeks, barrows on one side of the aisle and gilts on the other.'

Johnson likes the basic concept of wean-to-finish. 'It seemed like it would make sense to move the early weaned pigs from the sow farm to the finishing location and leave them there until marketing,' he remarks.

But he's quick to point out a 10-lb. pig doesn't really need the 8 sq. ft. of space needed at the end of their finishing period. 'That's a whole lot of space for a little bitty pig,' he declares.

His second big concern is the cost of maintaining group integrity. In a typical wean-to-finish facility, 1,000 or 1,200 pigs, there are 30-plus pigs/pen in one big open room and the sexes are separated by the middle aisle. 'You've got probably a 4- to 6-week time lag from the time the first barrow goes out to market to the last tail-end gilt or barrow (leaves), unless you market a lot of light hogs. And if you wanted to be all-in, all-out (AIAO), that building is not being fully utilized,' he charges.

So Johnson and his two business partners set out to design a wean-to-finish building that achieves their goal to better utilize space and cut building costs without compromising pig performance. That meant limited pig moves and no mixing or sorting of pigs.

An increasingly popular wean-to-finish management practice producers are using to better utilize space is double stocking newly weaned pigs. His goal was to come up with a method of double-stocking pigs without having to sort or mix them when half are moved.

Johnson's building plans are quite simple. Two, wean-to-finish buildings are designed with six pens per room, 10 rooms per building, plus a tail-end room in one building. (See Figures 1 and 2.)

At 2- to 3-weeks of age, pigs are split-sexed, half barrows and half gilts, 80/pen, 480/room. They get 4 sq. ft./pig until they reach 8-9 weeks of age --roughly 70 lb. Pigs are not split-sex-fed, however, because there is only one feed bin and one feed line to each room's three, double-sided feeders.

When the group is split in half, every other pen in the room is emptied. Pen integrity is maintained as the departing pigs stay in their pen groups as they move to an empty, wean-to-finish room for finishing.

Double Filling Pens As adjacent pens are emptied, divider gates on either side of the feeder/waterer island are swung open and attached to the hall gates and back walls, doubling the size of the pens. All it takes is lifting a rod out of the gate sections located on either side of the center feed/water island. Rods are attached in their new positions aligned with the other gates, Johnson says. These gates swing the same as an aisle gate. The other option is to simply remove the gate sections but that requires extra storage.

The result is the wean-to-finish room now contains three pens of 80 pigs, 240 head in all, providing 8 sq. ft./pig through finishing.

During the move from double to single filling, Johnson says either all the barrows or all the gilts will be transferred to another wean-to-finish room. At that time, they will be split-sex fed by room during their grower-finisher phase.

Johnson admits separating the sexes into different rooms won't eliminate variation in growth. But it will help reduce the weight spread at market age.

Tail-Enders And for that small percentage of finishers that still can't keep up, there are 16 small pens in the one tail-end room where fall-behinds can spend a week or two while the wean-to-finish rooms are washed and restocked. These pens are 8 ft. 8 in. wide x 9 ft. 4 in. long and can hold up to 10 pigs each, says Johnson. They are not adjustable.

The addition of the tail-end room makes one wean-to-finish building longer than the other -- 282 ft. vs. 302 ft. long. Both buildings are 80 ft. wide.

Tail-enders are the only pigs mixed or sorted off at market time at Johnson Farms. The tail-ender room does add a little bit extra to building cost. But it is considerably less than the sort loss producers often take when they ship light hogs to empty out a building, asserts Johnson.

The tail-end room will cost about $29,000 to construct. Johnson figures without this room, the operation would probably need at least two more wean-to-finish rooms, at a greater cost for each, to minimize sort loss.

'These buildings will flow about 13,000 pigs/year,' says Johnson. 'A sort loss of 50 cents/cwt. live weight would cost us $16,000/year, more than paying for the tail-end room. Our present sort loss is less than 10 cents/cwt., using tail-end rooms in our present buildings.'

Building Cost Savings Double stocking at Johnson Farms has kept building costs to $151/pig space, based on 8 sq. ft./pig. That's calculated from 6,880 pig spaces, figuring pigs move in at 21 -- 2 weeks of age and go out at 251 -- 2 weeks of age. That includes 9 weeks double-stocked and 14 weeks single-stocked.

He notes double filling improves use of feed and water equipment, too. Johnson and the Pates selected Farmweld dry finishing feeders and bowl waterers to use in the wean-to-finish buildings, and are satisfied with performance to date.

Production Flexibility The double-stock method allows for flexibility. Should there be a backup in other wean-to-finish rooms at the normal time to switch to single fill, it would be easy to stay at double fill for another week or two until the other rooms have emptied, explains Johnson.

There is one more pig move for half the pigs, compared to traditional wean-to-finish, but there really is no more washing involved. 'The only time you ever wash a room is when you empty it to market,' emphasizes Pate. As a room is emptied for market, half of the pigs in a double-stocked room simply walk down fully enclosed hallways to that recently cleaned room, while those that remain behind do not have their room cleaned, explains Johnson.

Rooms Self-Contained The idea to build wean-to-finish rooms self-contained actually started with an incident several years ago.

'Before our last expansion in 1993, our existing facilities weren't AIAO, everything was continuous flow and our finishers were one big room,' says Pate. There were lots of problems with Actinobacillus pleuropneumonia in grow-finish. Areas of a building were then walled off to separate air flow. It did not make a difference. The disease was still there.

'So we decided to go down and wall off the pits. I really didn't think it would work, but it cleared up the disease problem right away,' Pate says. Combined with walling off the pits, we switched to AIAO production and have managed to produce pigs without treating for the disease for 10 years.

Every wean-to-finish room has a separate, 8-ft.-deep pit under it, created by a dividing wall between the pits under each room, says Pate.

Observes Johnson: 'You've got to divide off your air spaces, whether by room or by building, to limit possible disease spread.' A solid section is also placed along the side of the pits under the hallways to prevent air flow from the pits to the hallways.

Each room in the new wean-to-finish buildings also has its own ventilation system with sidewall and pit fans, and air inlets out of the attic and from the hallway. 'There is a common hallway or plenum that feeds all of the rooms, but each room gets fresh air,' stresses Johnson. Evaporative cool cells on the outside hallway wall will provide cooling on hot summer days and hopefully improve performance.

Hanging radiant heaters are a key element to the success of the wean-to-finish units. Combined with black, rubber floor mats, they create a warm zone for the first critical months. The heaters can be quickly uncoupled, cleaned and moved to another room for the next new group of pigs.There is also one hanging space heater that stays permanently in each room.

The heat loss in these rooms will be very low because, except for the end rooms in each building, the only outside wall is the wall with the fans on it. All of the other walls are partition walls between adjoining rooms, says Johnson. Hallways are also heated. It is unlike a typical finisher building that has a lot of outside wall space --and a lot of open area to heat, he points out.

Marketing At market time, finishers walk down a wide hallway to a livestock truck parked in the load-out area. The load-out is inside the buildings, in the enclosed center area that connects the two wean-to-finish structures. The enclosed loading area will also be used to wash trucks and farm equipment.

Says Johnson: 'When it comes to marketing these hogs, we don't have to haul them or load them up or go outside or anything. We just walk them down the hall. In fact, we might just let them kind of load themselves.'