How to Deworm Pigs? | Schedule, Drugs & Best Practices

For the full breakdown, see our best Dewormer for Pigs guide.

Most parasite problems in pigs start the same way—treating the whole herd without knowing what’s there. The effective path to deworming pigs begins with a fecal test, not a syringe. This article covers when to treat, which products work, and the step-by-step process that keeps pigs healthy and keeps meat safe for consumption, whether you raise a few animals or a full herd.

When Should Pigs Be Dewormed?

The right deworming schedule depends on your herd’s parasite burden, housing system, and production stage—not a one-size-fits-all calendar. Fecal testing is the only reliable way to confirm whether treatment is needed and which worms are present before medicating the whole group. Regular testing also helps you track whether your current approach is working.

For breeding stock, extension guidance recommends deworming sows one week before breeding and again one week before farrowing. Growing pigs are typically treated around 6 to 8 weeks of age with a second dose 30 days later. In outdoor or dirt-lot systems, where worm eggs and larvae persist in the soil, pigs benefit from treatment every 30 to 60 days throughout the growing season, rotating drug classes when possible to slow resistance.

If threadworms are a known problem in your herd, some protocols treat baby pigs at 5 and 10 days of age with an appropriate oral product such as thiabendazole paste. Always let the fecal exam and your veterinarian guide the final schedule for your specific operation.

How to Deworm Pigs Step by Step

Deworming pigs requires accurate weights, correct product selection, proper administration technique, and environmental follow-through. Each step matters for effectiveness and for food safety when pigs are raised for meat.

Step 1: Weigh each pig. Dose calculations must come from body weight, not from age or visual estimate. Underdosing promotes drug resistance—a growing problem in swine operations—and overdosing increases safety risk for the animal and anyone handling the meat. A livestock scale is worth the investment if you raise multiple groups.

Step 2: Select the right product. Choose a dewormer labeled for swine and matched to the parasites your fecal test identified. Common options include ivermectin, fenbendazole, levamisole, pyrantel tartrate, and others.

Step 3: Administer correctly by the right route. Ivermectin and doramectin are given as a subcutaneous injection in the neck—never into the muscle. Fenbendazole is fed orally for 3 to 5 days. Pyrantel tartrate is added to the daily feed. Use proper restraint so the injection lands in the right spot and the full dose is consumed.

Step 4: Re-treat on the parasite’s cycle. Some products require a second dose 10 to 14 days later, others at 3 weeks or 30 days. The label instructions and your veterinary plan determine the interval. Re-treating too early wastes product; re-treating too late lets worms re-establish. Keep a simple log of treatment dates, products used, and withdrawal deadlines.

Step 5: Clean the environment. Deworming is temporary if pigs return to contaminated pens. Remove manure, improve drainage, provide dry bedding, and rotate paddocks when possible. Worm eggs and larvae survive in soil and manure for months—hygiene is half the program and the part most often overlooked.

Choosing a Dewormer: Common Products and Their Use

No single product works for every farm. The best choice depends on the parasites present, the pigs’ age and production stage, and whether the animals are raised for meat. Rotating drug classes over time is a standard recommendation to manage resistance, especially in herds that deworm regularly throughout the year.

Ivermectin is widely used for its broad-spectrum activity against roundworms, lice, and mites, and is injected subcutaneously in the neck. Fenbendazole, fed orally over several days, targets multiple internal worms and is often chosen for its safety margin in young pigs. Levamisole offers another option for roundworm control, available in feed or injectable form. Pyrantel tartrate is added to daily feed for continuous worm suppression and is common in starter rations. Dichlorvos and Hygromycin B also appear in some older protocols but should be checked against current FDA swine labeling before use, since not every product remains approved for every stage.

Whichever product you select, the label’s withdrawal time must be followed exactly for any pig destined for slaughter. That number varies by product—anywhere from a few days to several weeks—and is the most common oversight in on-farm deworming programs. Mark the end date on a calendar the same day you administer the dose.

FAQs

Can you deworm pigs naturally without chemicals?

Natural remedies such as diatomaceous earth or pumpkin seeds are not supported by veterinary research as a standalone method for deworming pigs. They may complement a targeted anthelmintic program, but should never replace fecal testing or FDA-labeled dewormers when parasites are confirmed.

How often should outdoor pigs be dewormed?

Outdoor and pasture-based pigs typically need treatment every 30 to 60 days during the growing season, because worm eggs and larvae survive longer in soil than in confinement systems. Fecal testing every few months helps determine whether that interval is right for your specific herd and conditions.

What happens if you overdose a pig on dewormer?

Overdosing can cause drooling, stumbling, or lethargy and may require veterinary attention. The more common farm problem is actually underdosing, which selects for drug-resistant worms. Always weigh the pig before dosing and measure the product carefully to get the dose right the first time.