Knocking Down Pneumonia

A carefully structured control program has guided a Minnesota swine operation to clean up Mycoplasmal pneumonia problems on several sow farms.

Because the organism is so pervasive, producer Mark Schwartz and consulting swine veterinarian Ross Kiehne are very reluctant to say that mycoplasma has been eliminated from three of nine sow farms in the Schwartz Farms system at Sleepy Eye, MN.

But they do agree that by closely following a six-step control program they've developed, those three sow farms haven't seen a reccurrence of problems.

“I don't know if we want to call this a mycoplasma disease elimination program, because I am not sure we have eliminated the disease from the farm,” stresses Kiehne, Swine Vet Center, St. Peter, MN. “But I think we have dropped mycoplasma to such a low level that we are not leaking it into piglets, reducing the respiratory challenge in wean-to-finish farms downstream.”

Typical Problems

Schwartz Farms is comprised of 25,000 sows on nine sites, ranging in size from 600 to 5,000 sows. All are farrow-to-wean operations and pigs flow to wean-to-finish sites at 18-20 days of age.

Schwartz Farms has faced mycoplasma problems typical of the swine industry — slow growth and tail-enders in grow-finish. When pigs hit an “18-week wall” in finishing, problems can become noteworthy, interrupting growth, decreasing group uniformity and increasing mortality rates, says Schwartz.

Part of the porcine respiratory disease complex (PRDC), mycoplasma has made other diseases like porcine reproductive and respiratory syndrome (PRRS), swine influenza virus and pasteurella multocida at Schwartz Farms worse.

Mastering Mycoplasma

Small European farms have a proven track record of reducing mycoplasma, says Kiehne.

Whether that could be adapted to larger farms was a key question for Kiehne and Schwartz.

At Schwartz Farms, cleanup started small and has advanced to larger herds. Cleanup was completed three years ago on a 600-sow site, followed by a 1,200-sow farm. Two years ago, a third, 2,500-sow farm was cleaned up. Cleanup of a fourth farm, a 5,000-sow operation, is to be underway soon, says Schwartz.

Goals for the three sow farm sites were to reduce the disease load, not disrupt production and eliminate pig vaccination. All goals were achieved and farms were cleaned up using six key steps:

• Use a proven mycoplasma-negative source of gilts to begin the project.

• Load up the sow farm with gilts to maintain production flow during this six-month control program.

• Mass-vaccinate all animals on the sow farm with at least two doses of vaccine, a minimum of two weeks apart, for breeding females. “A lot of times we have actually done a third sow vaccination two weeks later, trying to build as much immunity as we can and burn out that bug, knocking the level down as far as possible,” emphasizes Kiehne.

• Negative gilts are purchased and vaccinated twice for mycoplasma during isolation/acclimation (I/A), once shortly after arrival and the second time prior to being bred at the I/A unit. Gilts remain at the I/A site until they are ready to farrow before being transferred to the sow farm.

  The reason for extending gilt isolation from the standard 30-60 days to about four months is to keep the known negative gilts in I/A separated from the known mycoplasma-positive gilts on the positive sow farm, explains Kiehne.

  Gilts in I/A aren't exposed to any mycoplasma organisms from the sow farm, because the goal is to maintain gilts' negative status. Kiehne points out that gilts 10 months old and younger are the chief source of infection for mycoplasma in the breeding herd.

• About six weeks before the naïve gilts arrive from I/A to farrow, sows at the positive farm are placed on mycoplasma-approved feed medications for 14-21 days. A four-week pulse is started again one week prior to gilt entry.

• Also one week prior to gilt entry, all newborn piglets on the farm are injected with an antibiotic effective against mycoplasma. This process is repeated once a week for four weeks, says Kiehne.

During the control program, it was decided to reduce pig movement to avoid possible spread. Pigs were never held back if they fell behind, and crossfostering was limited as much as possible, says Schwartz.

Another key element of the PRRS control program is to ensure elimination of all open gilts before the new, negative gilts become part of the breeding herd. It's common to keep those animals back in an attempt to get them bred. “Don't retain open gilts, because they pose one of the last avenues of disease transfer to the negative gilts,” warns Kiehne.

Program Success

Kiehne says the six-step process has worked on the three Schwartz sow farms because management is committed to seeing the process through.

The approach has not been without its failures. Those cases have occurred when clients have skipped steps to save costs or labor, states Kiehne.

Schwartz Farms decided to stick to the program to see if the protocol was effective. The farm has not done a lot of testing during the cleanup phase, instead waiting to analyze results after completion.

The six months of the cleanup program ran around $20/sow for vaccine, medication, labor and site costs, estimates Kiehne.

Mark Schwartz is satisfied with the results, enjoying improved average daily gain, a reduction in ulcers from pigs going off feed and improved uniformity in downstream production groups. Pigs are no longer vaccinated for mycoplasma downstream.

And most importantly, no flare-ups of mycoplasma have occurred, he says.

Management Precautions

After cleanup, negative gilts are still vaccinated twice during I/A to provide some level of insurance against reinfection, adds Mark. All other mycoplasma vaccination and antibiotic programs have been discontinued.

About six months ago at the 2,500-sow farm, it was decided to start a monthly monitoring program. Ten mid-finishing and 10 late-finishing pigs were blood tested. So far, all have tested negative for mycoplasma.

Schwartz has also instituted a sentinel gilt testing program. Ten gilts out of a group are left unvaccinated. They are tested at regular intervals and identified with special tags indicating they are unvaccinated. This program has just started.

Concluding Observations

The mycoplasma control program has not helped eliminate PRRS from the sow farm nor the grow-finish farms downstream, but it has lessened the impact of PRDC on growth performance, says Schwartz.

A mycoplasma control effort is certainly not something that everyone should attempt, observes Schwartz. It is vital that the sow herd is stable, based on clinical observations before such a program is tried.

“I don't think that anyone should try this program when things are going really bad. It is only when the herd health program has been going good for a while that you can introduce this mycoplasma control program,” emphasizes Kiehne.

Don't spend the time and the money on this program if you aren't confident your gilt source is really able to provide mycoplasma-free stock. Test all incoming gilts to be sure,” Kiehne adds.