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Unique Sow Parity Segregation Plan Bolsters Herd Health

Coupled with sow herd reduction, efforts guide consolidation and resource conservation for this Michigan pork producer. In five short years, Bob Dykhuis expanded his sow herd from 5,000 to 20,000, riding a wave of mostly solid hog returns from 2002 through 2007. However, as he turned the calendar to 2008, industry profits suddenly disappeared, fueled by a sharp descent in hog prices and corresponding

In five short years, Bob Dykhuis expanded his sow herd from 5,000 to 20,000, riding a wave of mostly solid hog returns from 2002 through 2007.

However, as he turned the calendar to 2008, industry profits suddenly disappeared, fueled by a sharp descent in hog prices and corresponding escalation in production costs.

Plus, the losses and treatment costs of managing Actinobacillus pleuropneumonia (APP) and porcine reproductive and respiratory syndrome (PRRS) added to the economic downturn for this Holland, MI, producer.

Quick Action

Dykhuis acted decisively. In April 2008, he decided to shave 15% off the sow herd, reducing it to 17,000 sows.

“We think this action reduces our cash outlay and our need for debt, and just strengthens our operation. We are following through on this and other cost-cutting measures (see sidebar) because we have seen that our overall economy is not going to be out of the woods anytime soon,” he relates.

Dykhuis also decided to phase out some older, more inefficient barns under grower contracts, and consolidate and utilize more topnotch growers closer to home in northern Indiana and southern Michigan.

Dykhuis had a whole series of new barns being built in the last year or so, some in northern Indiana, to serve as finishers to absorb some of the company's weaned pig production. A dedicated site was also selected just south of the Holland, MI, area to raise replacement gilts.

New Depopulation Strategy

For years, Dykhuis Farms attempted to improve herd health using rolling depopulations. But these failed to root out APP or PRRS, and were replaced with complete site cleanups.

“With rolling depopulation, you are taking out the old sows and replacing them with new ones, but you are not emptying the barn as you would with complete depopulations,” he says.

Total site cleanups take five months to complete and offer many advantages. “It is a great time to empty the facility, clean and disinfect everything and make all of the necessary building repairs,” he says.

Strict parity segregation and total site depopulations have helped eliminate APP, which produced a performance-robbing cough; positive and negative sows couldn't be mixed.

For PRRS, those steps have helped Dykhuis learn to live with the stealthy virus. PRRS produces few symptoms but drags down efficiency, and strains evolve to survive.

Sow Herd Structure Changes

The new parity segregation plan initiated by Dykhuis and his staff was an integral part of the farrow-to-finish operation's overhaul, and started during the early part of 2008.

Normally with parity segregation, gilts are raised to maturity on an isolated site, then join the main sow herd after farrowing their first litter.

But to upgrade the farm's PIC herd health profile, Dykhuis opted to advance the concept of parity segregation much further.

“In a sense, it all starts with the 2,000-sow grandparent herd that raises gilt replacements for all of the other herds and for itself,” he says. “That's at the top of the pyramid.”

Those replacements are developed in off-site facilities in the Holland area. “Those gilts come from the grandparent herd, and are weaned at 21-plus days. The idea is to try and get them exposed to the cloud of PRRS virus in the area. We want them to seroconvert (produce an immune response) to a PRRS virus challenge,” Dykhuis explains. Gilts are also typically vaccinated once, in the nursery phase, with the modified-live-virus PRRS vaccine from Boehringer Ingelheim.

After gilts have completed their first parity, they move to one of five, 2,500- to 3,000-sow complexes in the parity segregation rotation. These sites are all located within a few miles of each other in the Holland area.

The central concept behind this parity segregation plan, Dykhuis says, is that each sow complex in the rotation maintains its own parity distribution integrity, which means the age of the entire sow herd essentially ranges from Parity 1 through Parity 5.

Dykhuis' goal is to develop 50 gilts a week for the grandparent herd and add 200 gilts/week to the commercial breeding herd. After having their first litter, the Parity 1 sows are held in an off-site location until one of the five sow sites has completed the depopulation process.

Once a farm is depopulated, all of the new gilts will restock that farm and the sow farm rotation continues. That process is repeated for all five sow complexes over time.

“All of the sows are grouped on farms in a big circle because this is a rotation for parities,” Dykhuis explains. “Every one of these sites has a different parity in it.”

The only time the integrity of the individualized-parity sow farms changes is if some sows are “backloaded” — added later to keep a sow farm full. Usually, only older parity sows are added to an older parity sow farm to match levels of immunity, he comments.

One of these older parity sow farms will always be in the process of being depopulated, “pushed out by new PIC breeding females,” he says.

With this parity segregation approach, that forces sows out at Parity 5 or so, sows aren't culled so much for age, but rather for their failure to cycle or for unsoundness.

A group of sows will be isolated if they become unstable for the PRRS virus. APP has been eliminated from the operation.

PRRS Testing

To better manage PRRS, which has plagued Dykhuis Farms for over 20 years, Dykhuis took the advice of new consulting swine veterinarian Tim Loula, Swine Vet Center, St. Peter, MN, to initiate a PRRS blood testing protocol. That work is coordinated by Erin Ehinger, Dykhuis' eldest daughter, who manages the sow farms. Duane Long, DVM, Peru, IN, consults twice a month, doing pig/sow work.

Monthly blood samples, taken on 15 piglets from each sow unit, are pooled in samples of five to check for PRRS status. Sow farm staff pulls blood samples from the oldest, sickest pigs in the group. Office personnel are trained to use the farm's own centrifuge to process samples and ship to the diagnostic lab at Iowa State University.

Frequent sampling helps determine which sow herds can be mixed as needed, Dykhuis says.

“The key to PRRS is separation, really building immunity and knowing what (strains) you have,” Dykhuis says. “That is why we are involved with sequencing of the strains (with Iowa State University). When it appears you have a new outbreak, you can keep those animals separate.”

Dykhuis believes that most PRRS strains sneak in through gilts during their development process in southern Michigan. He feels the concentration of hogs allows PRRS viruses to swirl around, just as pseudorabies virus did before it was eradicated decades earlier.

But PRRS has proven to be a much tougher disease to eradicate. As sows age, they become susceptible to new PRRS strains that invade the region.

“Before sequencing, we didn't know what virus strains we had. We just thought it was PRRS virus. With sequencing, we know there are different strains of PRRS, and that you can have immunity to one strain but not to another strain coming in. Consequently, previously infected sows can get reinfected,” Dykhuis notes.

Just as importantly, blood testing a percentage of the weaned pigs helps monitor PRRS status to determine which groups can be mixed in wean-to-finish flows, and which ones can't. Weaned pigs move to 4,000-head, tunnel-ventilated finishers. Two rooms of pigs can be transported to a site in one of two dedicated trailers.

Collecting and pooling PRRS blood samples for shipment saves Dykhuis' operation money and time. He says the tipoff that additional testing needs to be done is when more than 2% of the breeding herd aborts their litters.

A key sign of PRRS infection in the Dykhuis system is that “pigs start hard” after weaning. “If they have PRRS, then they don't want to eat or they have secondary infections that are slowing them down,” he explains.

A USDA grant will be used to determine if a regional PRRS cleanup plan can be developed for hog-dense sections of southern Michigan, under the direction of Barb Straw, DVM, Michigan State University.

Small Pig Flows

To improve health and productivity, weaning age was extended to a minimum of 21 days a few years ago, and a lot of farrowing crates were added to all of the sow farms, Dykhuis explains.

This action also increased the number of “opportunity pigs,” undersized (8 lb. or less) but otherwise healthy at weaning.

To save these small but challenged pigs, a weekly, small-pig flow strategy was started. Each week, roughly 500-600 pigs from all of the farm's farrowings are flowed into a 6,000-head, off-site nursery. These pigs are fed out in a series of isolated finishers.

“We know there is a little higher death loss and a medication cost with these pigs, but removing the smallest 5-6% of the piglets from the farrowing rooms just makes the majority of pigs on those farms perform better.

“Those small pigs are actually healthy, but they never catch up in growth to the normal pigs. This way, they can get the right feed and medication, and then the percentage sold out of the finisher is similar to the rest of the group,” Dykhuis attests.

Those “opportunity pigs” end up being as uniform as the conventional group, but finish about three weeks later.

TAGS: Reproduction