Worming pigs should be common sense. But when a study shows 70% of pig livers from slaughter houses in the U.S. are being discarded due to worms, it’s time for the swine industry to take better care of their beloved bacon.

It’s not that owners don’t try to provide the best kind of care for their hogs, but the basic health practice of worming pigs cannot be overlooked.

Todd Price, owner of North Central Veterinary Services in Upper Sandusky, Ohio, says roundworms, lungworms and whipworms are extremely harmful to the health of a pig. Show families buying a pig in good health still need to continue a vaccination and health program, which includes keeping their prized show animal on a regular worming schedule.

Price says it’s important to start early and worm a show pig two to three weeks after they get to their new home. Before this, breeders should have wormed the sows before they had the pigs as well as the baby pigs three weeks after putting them on a solid concrete or chip-covered floor.

Worm larvae can live in dirt, grass as well as on solid concrete floor or any type of floor that does not drain the contaminated feces. Once roundworms are ingested they grow into pencil-shaped parasites. They lay eggs and these larvae migrate through the bowel wall and into the pig’s liver via the lymphatic draining system. Price says once in the liver the larvae migrate through tissue to get to the blood supply then head to the lungs. Next they migrate from the blood vessels to the airways and are coughed up and swallowed, thus completing the life cycle.  

When inspectors see an infected liver in a pig carcass, they throw the liver out because it cannot be used for consumption. Price says 70% of livers are thrown away from show pigs that are slaughtered, which tells him owners are not worming their pigs early — or often — enough.

“Many people don’t think about it or they do it too late,” Price says. “The liver damage from the worm larvae migration can be seen for more than a month after the larval migration occurred. If the animal has worms and the owner waits and waits until right before the fair then de-worm the pig, it’s too late. They should have done it two months earlier.”

Price says worms cause damage by pulling nutrients from a pig. Worms live in the pigs’ intestines and take 5% to 10% of the pig’s daily intake. If a pig is supplying worms with nutrition, then the animal is not getting the essential nutrients it needs to grow. A more severe threat is the whipworm, which can actually kill a pig because it affects the animal’s large bowel. This worm attaches to the wall of the large bowel and then “whips” its tail back and forth, tearing up the internal lining of the pig’s bowel. This section of the bowel is normally responsible for maintaining hydration, so once it is damaged the pig can become dehydrated while also losing blood in the stool. Being dehydrated means the pig can quickly die.

A common misconception is that whipworms, round worms and lung worms don’t live in the same environment. In fact, Price says they each live anywhere in the country on both dirt and concrete. Even concrete that’s been washed with disinfectant won’t remove the eggs. The key, Price says, is to wash flooring with hot water at 3,500 PSI to effectively remove the eggs off the concrete. If possible, an owner should flame or seal the concrete with normal concrete sealer. This cleaning process must be repeated each season before new pigs are brought in.

All sows and gilts should be wormed immediately before farrowing, and it’s usually best to be done when they are first placed into the farrowing crate. Hog farmers should also keep in mind the withdrawal time for wormer is dependent on what product they use so make sure to adhere to the manufacturers drug withdraw times.

It’s also important to worm on the right schedule — and not all the time.

“Show barrows and gilts need to be dewormed every six to eight weeks,” Price says. “Worming more often than this could hinder the process because it can induce resistance. Plus, there are multiple stages of worms, so keeping a six to eight-week schedule assures you will get all of the proper larval phases as they mature.”

Some feed products include wormers in them. A top dress option would be Safe-Guard (Scoop A Sow). Price says this can be fed in dry or slopped show pig feed, and he recommends feeding the top dress or show feed with wormer for three to seven days each time depending on the manufacturer, and to always follow label directions.

Injectable wormers such as Ivomec or Dectomax are also good because they take care of mange and lice on pigs. However, these injectable products do not work for whipworms. If an owner sees blood in their pig's stool, then whipworm infestation is a probable cause and immediate attention is needed. Indications of worm infections in a pig also include a thick hair coat, loss of condition and a slower growth rate for the animal.

Price says hog farmers must remember they are raising an animal that is part of the food chain. Raising livestock means caring for an animal and producing a safe and wholesome pork product for consumers to enjoy.

“We are responsible, as swine owners, to maintain the market for pork,” Price says. “Whether we are producing 100,000 market pigs a year in a commercial setting, or two barrows for a 4-H project, we are all responsible for producing safe and wholesome pork.”

McCurry writes from Colwich, Kansas