Will we ever control Mycoplasmal pneumonia problems in pigs? We've tried all kinds of new technology: segregated early weaning (SEW), medicated early weaning (MEW) and three-site production, just to name a few.
All these things, various vaccines and strategic medication programs have helped in our efforts to meet rising performance expectations. But the bugs seem to find ways to mutate and survive. So, where do we go from here?
Most of you recall that chronic cough in the last nursery stage of single-site production systems. We recognized this was infection and there was seroconversion to the farm's respiratory organisms.
The list was led by Mycoplasmal pneumonia, precursor to other secondary bacterial organisms. Now we have added viruses like Porcine Reproductive and Respiratory Syndrome (PRRS) and Swine Influenza Virus (SIV) to the mix.
The industry responded with new technology. Things got better, but in many cases it just put off the infection and seroconversion until later.
The population of older grower pigs became infected by the few "Typhoid Mary" pigs that got through the system or became infected from exposure that blew in from the surrounding area. This has made control of these respiratory organisms more difficult and the results inconsistent at best.
Case Study No. 1 The grow-finish manager of a 600-sow, farrow-to-finish farm had a respiratory break in one, 2-week room in the finishing complex. The farm is a multi-site, single-site system with breed-to-wean, nursery and finishing complexes 200 yards apart.
We observed excessive coughing, thumpers and increased death loss in only that one room. Autopsies revealed the start of mycoplasma-like lesions, fibrin and signs of viral involvement, probably PRRS.
We just completed a quarterly serological profile in the nursery and grow-finish complexes. We collected serums from late nursery, grower and market-ready pigs at one time. This gave us a "slice-in-time" profile rather than a serial bleeding of the same pigs as they grow through the system.
The pigs at 60 lb. in the late nursery and at 120 lb. in the grower were negative for mycoplasma, Actinobacillus pleuropneumonia (APP) and PRRS. The sow herd was positive for mycoplasma and PRRS. Market pig tests showed they became positive for PRRS and mycoplasma late in the grower or early finisher stage.
The farm was using two doses of mycoplasma vaccine, but had stopped for summer-finished pigs. We chose to attack the mycoplasma fraction of the respiratory break and water medicated the room and some individuals. They responded well.
We also administered one dose of mycoplasma vaccine to younger finishing pigs. In addition, we highly recommended that the farm reinstate a quality mycoplasma vaccination. It would appear on this farm that as long as we address mycoplasma control, we'll make it through the PRRS infection. The farm is working well now.
Case Study No. 2 During a regular quarterly herd visit at a 600-sow farm, we discussed a severe respiratory disease. All parts of production were affected. The sows were coughing, off feed and some were aborting. A high percentage of suckling, nursery, grower and finisher pigs were coughing. Virtually the whole farm was sick within a few days. Clinically, the type of cough and the sudden onset for all ages of pigs pointed to SIV.
We knew the breeding herd was serologically positive to SIV biotype H1N1.
They had also recently received their semiannual SIV vaccine as a blanket whole breeding herd immunization about one month earlier.
Testing confirmed the farm was infected with the new SIV strain, H3N2. The herd was very susceptible because the farm population had never been exposed to this new strain; the commercial vaccines for H1N1 didn't protect against it.
There was a big increase in thumpers and individual treatment rate. This farm was mycoplasma positive but slaughter checks and routine autopsies indicated it was under control.
The farm was all-in, all-out by room and used a time-tested vaccination program for mycoplasma. We chose to sacrifice some pigs and do autopsies. The level of Mycoplasmal pneumonia, if at all, was normal. Signs of viral pneumonia were common.
We treated secondary bacterial invaders by pulsing high levels of feed medication for 10-14 days, as needed. Individual treatments continued for about two weeks and problems subsided.
Sadly, about two months later, routine slaughter check indicated a doubling of lung scores. Lung lesions were mycoplasma, complicated by secondary bacteria. A lab confirmed our observation. The farm, with no treatment changes, had returned to its normal level of infection.
Can mycoplasma be eliminated? Intensive hog farming makes it a tough disease to keep out. If your farm is isolated, and you can purchase mycoplasma-free stock, eradication may be an option.