Even though it’s August, now is not the time to overlook the impact that mosquito bites can have on your pigs.

High numbers of mosquitoes this summer mean more bites on pigs and higher trim losses at packing plants, says Mike Brumm, University of Nebraska swine specialist.

“Increased carcass trim will cost producers anywhere from $5 to $10 per pig,” says Brumm. “If you raise pigs in curtain-sided barns, you’ve seen pigs with more red welts. This is a huge problem in the industry right now.”

While pigs get mosquito bites, they are not carriers of West Nile virus, he adds. “If a mosquito bites a pig that previously had been bitten by a mosquito carrying West Nile virus, the new biting mosquito won’t get infected. The main problem is the bites themselves.”

USDA inspectors are asking that packing plant workers trim areas on carcasses with red, raised welts.

“Since mosquitoes can spread other diseases to livestock and humans, it’s important to reduce favorable mosquito breeding sites,” says Brumm.

“Treating the facility, not the pigs, is the key to prevention,” says Eric Newman, DVM, National Pork Board. “Producers can take several steps in the weeks prior to the hogs’ anticipated marketing date to help minimize this costly problem.”

  • Eliminate areas of standing water. Brumm points out that livestock lagoons are seldom sources for mosquito breeding because they contain too much organic matter and produce too much wave action.
  • Mow grass and trim weeds around swine facilities.
  • Careful use of insecticides labeled for use in swine buildings. Insecticides containing permethrin will repel mosquitoes and biting flies before they bite as well as kill those that do successfully feed on the swine. Use only products labeled for use on swine or in swine buildings and follow the pre-slaughter withdrawal periods listed for the product. You can contract this task out to ensure that it gets done on a regular basis.
  • Apply insect screens to swine buildings; assess the cost, maintenance, and impact on air circulation before implementing this option. Monitor the air flow once the screens are installed to ensure that ventilation is still correct.
  • Talk with your veterinarian to be sure that any lesions causing trim or carcass loss are a result of insect bites and not due to other infectious causes such as erysipelas, swine pox or mange.