Mycoplasma pneumonia continues to trouble the swine industry. Around for years, the respiratory disease caused by the bacterium Mycoplasma hyopnueumoniae reduces pig performance, especially when mixed with other diseases such as porcine reproductive and respiratory syndrome and influenza.
“Only recently have we identified the ongoing costs of (mycoplasma),” Joe Connor, DVM, president of Carthage Veterinary Service, told Pig Health Today. “That’s really what has driven our focus on control methods.”
In addition, some hog farms undertake elimination of mycoplasma. About 10% of swine herds have been successful in eliminating mycoplasma. Moving that percentage higher will take work, Connor added.
Prevention and control
A mycoplasma-prevention plan for grower pigs begins with young, growing gilts before entering the sow herd.
“An infected animal can shed (mycoplasma) bacteria for up to 250 days,” Connor said. “If we expose the young gilt to natural infection, she will not be shedding when she farrows her first time. That is a critical part of the control.”
The second part of control is vaccination of pigs or piglets, depending on the activity of the growing population.
The third part is a strategically placed antibiotic during the active phase and the growing phase of the pig. Diagnostic tools help veterinarians determine when to administer an antibiotic intervention, usually a medication in the feed for 21 days.
Where, when to use injectables
Injectable antibiotics are important tools for managing mycoplasma, depending on the prevalence of the disease at weaning and in grow-finish pigs, Connor said.
“If the pig is clinically showing signs of mycoplasma, we would use an (injectable) antibiotic,” he explained. The clinical signs include a dry, long-duration cough; respiratory activity not necessarily related to the cough; and mortality.
“Most of us use a threshold of a certain number of pigs that die over a short period of time as a trigger to go in and be more aggressive with individual treatments,” Connor said.
“We do know that if a caregiver can detect pigs needing treatment, individual pig treatment remains the most cost-effective strategy we have, even for bacterial agents such as mycoplasma,” he added.
A number of herds have eliminated mycoplasma — enough herds to determine the key steps for being successful. However, some of the mycoplasma-negative herds become infected with the route of introduction unknown.
“At the same time as we increase pig density, we’re always looking to eliminate bacterial or viral infections to take them out of the spectrum of combined infections,” Connor added. This will always include mycoplasma.
Recently, studies showed aerosol transmission of mycoplasma is “not as frequent as what we thought in the past,” he said. This provides hope that the number of mycoplasma-free herds will slowly increase in the future.