Mycoplasmal pneumonia still exists on a majority of commercial hog farms.

Mycoplasma is a long-term villain to the swine industry, although with the likes of porcine reproductive and respiratory syndrome (PRRS) and porcine circovirus-associated disease (PCVAD), it does not receive the attention that it once did.

Mycoplasmal pneumonia continues to exist on a majority of commercial farms, even with the advent of multiple-site production, numerous commercial vaccines and multiple feed/water medications.

Case Study No. 1

In the summer of 2007, a large system began experiencing several respiratory episodes in mid-to-late finishing. Clinically, pigs exhibited a dry, hacking cough even though they appeared active. Some producers reported reduced feed consumption, and normally 2-3 weeks later an increase in ulcers and Hemorrhagic Bowl Syndrome. Increased cull pigs and late-term death loss occurred.

The system practiced multiple-site production. Mycoplasma-negative gilts were purchased and vaccinated prior to entry into the breeding herd. Pigs were vaccinated with a commercial, one-dose product at 3-6 weeks of age.

Therer was little evidence of Mycoplasma for 2½ years after implementation of the vaccination programs.

Diagnostics from cross-sectional blood testing and tissue sampling were positive for Mycoplasma and secondary bacterial infection. Samples were negative for PRRS, swine influenza virus (SIV) and PCVAD.

As time progressed, it became apparent that a majority of the finishing pigs breaking with Mycoplasma originated from a particular commingled nursery site. Further investigation revealed the nursery site had hired a new vaccination team. The crew had been appropriately trained, but the owners questioned whether vaccination was being completed properly.

A different crew is now vaccinating pigs at this nursery. At the same time, vaccination protocols at other nursery and wean-to-finish sites in the system were reviewed. Proper timing, needle length, and education on the importance of Mycoplasma control to the entire system were reemphasized.

The increased attention to education demonstrated the importance of continually monitoring all farm protocols. We are now awaiting the results from these intensified efforts.

Case Study No. 2

A 600-sow, farrow-to-feeder pig site had complaints of increased gilt culling and mortality resulting from lameness. The farm isolates/acclimates gilts for 45-60 days, where they are vaccinated twice for Mycoplasma.

Working with the breeding crew, it appeared that most of the gilts demonstrated lameness around 60 days after introduction to the breeding facilities. On examination, the gilts had good body scores, but were reluctant to get up and bear weight on their rear limbs. Spraddle legs were typical. Individual animal treatments with antibiotics and inflammitories provided marginal response.

Multiple samples were submitted to the diagnostic lab before the Mycoplasma hyosynoviae was isolated from the affected joints. Keep in mind that Mycoplasmal hyosynoviae and Mycoplasmal pneumonia are two different organisms, and that presently there are no commercial vaccines for Mycoplasmal hyosynoviae.

In this case, a feed medication protocol was initiated during acclimation, and we made sure that injectable products were effective against Mycoplasma. More time is needed to evaluate these interventions.

Case Study No. 3

A large farrow-to-finish operation with multiple-site production complained of elevated nursery mortality. Nursery rooms are all-in, all-out, though air space is shared with multiple ages of pigs. The farm vaccinates for Mycoplasma at weaning with a commercial one-dose product and a commercial one-dose circovirus vaccine. The farm is PRRS-negative.

Examination of nursery pigs revealed a moist cough, thumping and emaciation of pigs 2-3 weeks post-weaning. The number of pigs affected was too great for individual pig treatment. Necropsies demonstrated over 50% of pigs with severe lung consolidations and adhesions consistent with Streptococcus suis or Haemophilus parasuis.

Intensive diagnostics through cross-sectional blood testing and necropsies revealed the presence of SIV H3N2, Mycoplasma and Strep suis. The sow SIV vaccination protocols are being changed, and new water medication strategies are being implemented in the early nursery to help reduce Mycoplasma and secondary bacterial infections. Mycoplasma elimination strategies will be discussed on this farm next spring. Early evaluation of our interventions looks promising.

Summary

With the multitude of bacterial and viral agents present today, it is important to work closely with your herd veterinarian for a complete and thorough workup before outlining preventative and treatment therapies.