With the majority of U.S. pigs finished in confinement style facilities, a 12-pound weaned pig will spend at least four months on slatted concrete floors. As the industry moves from gestation stalls to group housing designs, slat quality becomes an important factor. Rather than being confined to a small slatted area, sow movement over an entire slatted pen subjects them potential injury from defective flooring design.
Good concrete slat design, construction, and maintenance can minimize foot and leg problems associated with swine production.
The most critical feature in slat design is producing slats with a flat top surface. Slats with uneven and inconsistent surface place additional stress on pig’s feet and joints.
Many methods used for producing concrete slats consist of placing wet cast concrete into multiple steel forms and hand troweling to finish. It is harder to build slats with a consistently flat surface by hand finishing methods.
Machined slats are produced with a different process that eliminates the uneven surface found on hand cast slats. Automated Rotoscreeds “strike off” the mold creating a level, uniformly flat top that is easier for pigs to move across.
Slat longevity is an important consideration as worn or damaged areas create uneven surfaces that can injure pigs. Slats built using concrete with a low water-to-cement ratio are longer lasting and more resistant to wear.
The water-cement ratio refers to the ratio of the water weight to the cement weight used in a concrete mix. A lower ratio leads to higher strength and durability but makes the mix difficult to work with and form. For this reason, most slats are produced with wet cast concrete using a water-cement ratio of 0.5. Machined slats are manufactured from dry cast concrete with a water-cement ratio of less than .39.
A cubic yard of wet cast concrete formulated with 500 pounds of cement contains 250 pounds of water, while a dry cast mix only contains 195 pounds. As the excess water leaves during the curing process, it creates microscopic pores that reduce the final strength of a slat. Compromised slat strength can lead to many problems down the road, including expensive repairs, equipment damage and injury to pigs and farm personnel.
Maintaining surfaces and edges of slats, as they wear over time, is essential in providing pigs with a comfortable flooring surface. Areas around waterers and feeders are the first to show significant damage. When the need arises for concrete slat repair, choose a repair mortar designed for slat repair versus generic concrete repair products. Mortars designed for slat repairs feature cement and epoxy formulations with higher cure strengths and faster cure times. The amount of damage will determine the type of repair product needed. For simple repairs, less than 1/4″ in depth, a cost effective cement mortar can be used. More severe corrosion requires the use of epoxy mortars to hold the repair patch in place. Hog Slat offers a complete range of concrete repair products from Vanberg Specialized Coatings that can be used to repair worn and damaged slats with minimal downtime. For more information on slat repairs see the DIY video at http://www.hogslat.com/con-korite-xtra-mortar-kit.
Choosing concrete slats with a level surface and uniform openings provide growing pigs and group housed sows with secure footing to minimize foot and joint injuries.
To learn more about Hog Slat’s machine produced slats go to http://www.hogslat.com/concrete-slats.
Download Hog Slat’s new handbook discussing group sow housing. The handbook highlights Hog Slat’s field experience in constructing and converting over 300,000 sow spaces to group housing with feeding stanchions.
The handbook begins by comparing merits of different systems available for group housing. Complete with illustrated pictures of equipment and diagrams of building layouts, this 16 page handbook contains practical details needed to build new sow housing or convert existing stalls to group housing.
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Murphy-Brown’s North Division has completed one of the largest stall to group housing conversions in the industry. All the company farms have been converted to group housing over the last four years; 58,000 sows in total. Keith Allen, General Manager of the North Division, discussed the conversion.
Keith, how did you decide on the type of group system?
“Long before we announced our conversion plans, we toured several types of housing systems abroad; ESF (Electronic Sow Feeding), Free-Access stalls and Pens with feeding stations or Stanchions. We felt stanchions would require the least amount of cost and would be easiest to manage. The results four years post conversion support that decision.”
Can you explain that a little further?
“Our production records validate improvements for any metric you can compare, pig/born, pigs weaned, etc. The company farm production records rank better than most contract growers with stall gestation. Sow mortally is neutral when compared to traditional stall operations in the system. Fighting is less than we expected. Although we anticipated higher feed consumption in gestation, it also has remained neutral.”
Do you manage any other types of group housing systems to compare stanchions to?
“We have a large 10,500-sow unit with ESF feeding stations. The repair and maintenance of the feeding stations requires a full time employee on this operation. There is extra labor involved with the management of the animals. Every day the computer system prints a list of animals that didn’t record entry into the ESF from the previous day. An employee must locate those animals and identify why; Is she sick? Did she lose her tag? Is the feeding station in need of repair? Etc.”
“We just don’t have the extra labor costs or the maintenance in our stanchion type barns.”
“Free access stalls don’t have the same issues, but are more expensive to construct and present an increased opportunity of equipment failure with the gate latching mechanism. There is also a chance an employee inadvertently or purposely could lock the animals in the stalls, and then we really don’t have loose pen housing anymore.”
How did the transition go on the farms?
“The transition was seamless; our employees now prefer stanchions to the stall system we used before.”
What are basic design requirements you used?
“We designed the pens to hold six sows with 24 square feet per animal; there is one feeding stanchion per sow. The stanchions are 24” wide, and the dividers are 18” long. The length of the divider is important; this divider should be long enough to extend past the shoulders. By extending past her shoulder, she feels more comfortable and secure when eating.”
“The facility design provides breeding stalls to house sows for 35 to 42 days post insemination. After preg-checking, sows are grouped by size and moved to the pens.”
“An additional 3-5% of stalls have been added in the Group Housed gestation barns to provide critical care space for any animals that may require extra care or must be removed from the pens.”
Have you made changes to the design over time since beginning the conversion?
“Yes, our original layouts allowed for 7% extra stalls in the group housed gestation barns…..we have since cut that back to only 3-5%.”
“We have also realized it is unnecessary to have an alleyway between rows in group housed gestation. We simply mount the stanchions and sow feed drops head to head. One of the things you lose with group housing is the ability to regulate individual feed intake…..you manage by pens, so there isn’t a lot of adjustment to the drops.”
“We also have added “Access Doors” to the pen dividers to make it easier to walk from pen to pen. These consist of two posts set far enough apart that a person can squeeze through with a swinging solid divider on top to prevent the animals from attempting to go over the opening. We no longer have to climb pen dividers to check sows.”
How have the changes been viewed by Smithfield’s customers?
“I have personally toured many representatives from large food companies through our remodeled facilities. These companies made public commitments to securing pork from “stall-free” producers by a named date….they are listening to the consumer and committed to their long term Sustainability Programs. In every case, the reps remarked how well cared for the animals seemed to be and remarked how clean the facilities were. We think we have answered their concerns with this type of group housing.”