Swine Parasite Control - Ectoparasites

Parasites can be damaging to swine, causing unthriftiness and slow weight gains. These pests feed and reproduce on the host animal at the animal's expense. This is extremely hard on young, actively growing pigs. The extra stress associated with a parasite infestation can cause slow weight gains adding up to more feed required per pound of gain than with a clean pig.

Hog Louse - Haematopinus suis

The hog louse, a blood sucking pest, is the only louse found on swine. The louse is rather broad and has a length of about ¼ inch (5-6mm). This makes it one of the largest lice found on domestic animals. The color pattern is grayish-brown with brown to black markings. The hog louse will sometimes have a bluish coloration because of its blood sucking habit. Infestations of this insect will often start around the ears and will spread, if not controlled, to other areas of the body.

Hog Louse Life Cycle

The hog louse is dependent upon swine for survival and will generally not attack other animals. If a louse becomes dislodged from the pig, it will live for only 2 to 3 days. The adult female attaches her eggs to hair shafts and may lay as many as 90 eggs over a 25-day period. The young lice or nymphs emerge from the eggs in 12-30 days depending on environmental conditions. The nymphs will go through three developmental stages, all of which feed on blood, before reaching the adult stage. The average life span for male and female lice is about 35 days.

Hog Lice Damage

Lice, adults as well as nymphs, feed frequently by puncturing the skin to ingest blood. This causes irritation and can cause the pigs to seek relief by scratching and rubbing against any available object. As they increase, lice can cause an unthrifty condition in swine because of restlessness and improper feeding. This will ultimately lead to slowed growth and inefficient weight gains. Anemia has been observed in young pigs because of heavy lice infestations.

Hog lice may be found at any time of the year, but lice numbers tend to be higher during the winter and spring months. You should check regularly for the presence of this insect and start a control program if any are found. Check areas around the ears if any undue scratching and rubbing are noticed. These insects can be effectively controlled with several insecticides. Control materials are available as sprays, dusts, pour-ons, and injectables.

Hog Mange Mite - Sarcoptes scabiei suis

Parasitic mites of the burrowing type cause a skin inflammation on domestic animals that is referred to as mange. The most common mite of this type found on swine is the sarcoptic or itch mite. The body of the mite is white to gray in color, and the adult mite has four pairs of short legs. Infestations may initially be found on the inner or outer surface of the ear, around the eyes, or along the top of the neck and shoulders. The infestation will eventually spread over the body if allowed to go unchecked.

Hog Mange Life Cycle

The entire life cycle of this pest occurs on the pig. The life cycle stages are egg, larvae, nymph, and adult. If dislodged from the pig, the mites or eggs can survive 2 to 4 weeks if they are in a moist, protected place. These mites are, however, sensitive to drying, and if exposed to direct sunlight or dry surroundings, they will not survive for more than 24 to 48 hours.

The adult female mite deposits her eggs in tunnels that are burrowed just beneath the skin surface. As many as 20 to 40 eggs may be deposited over a period of about 30 days. The eggs will hatch in about 5 days, and the larvae may remain in the parent tunnel or start new tunnels. The cycle from egg to fertilized female takes 10 to 15 days. Many generations of mites may be present on an individual pig.

Hog Mange Damage

Mature female mites cause the most damage. This is probably so because the female adults are active in egg laying as well as feeding. Depending on conditions, it will take 3 to 6 weeks from time of infestation until the symptoms can be seen. Small, red-colored blisters will first appear and initially be covered with dry, bran-like scales. Later, a dark crust develops. The skin becomes thickened, rough, and dry. The intense irritation causes the pig to scratch and rub vigorously. This scratching irritates the skin and causes a serum to flow that dries and forms more crusts on the surface. In advanced cases, an offensive odor may come from the lesions. Because of the serious irritation associated with this parasite, swine, especially young pigs, will not feed properly and thus will not gain weight efficiently.

To make positive diagnosis of sarcoptic mange, the mites must be identified in skin scrapings. These scrapings can be done with a blunt scalpel or blade and made deep enough to draw blood. The edges of active skin lesions are a good place to look for mites. Oozing material from the outside of the ear is also a good place to look for the presence of mange mites. These scrapings should be viewed with a strong lens or preferably under a microscope.

Hog Lice and Mange Mite Controls

If moderate to high numbers of lice are present, two applications will be needed for effective control. In the case of mange mites, two applications would be advisable because of the protected state in which this pest lives. With both parasites, the second application should be applied 10 to 14 days following the first. Once infestations are cleared up, new animals should be isolated. This will give you time to observe new animals for any signs of pests that may serve as a source of reinfestation, particularly if mange mites are involved.

Housefly - Musca domestica

Control of houseflies is a problem for most livestock producers including the swine producer. The problem is caused by the ideal breeding and feeding sites that exist around barns. Although houseflies cause very little, if any, direct damage to pigs, they are a major nuisance pest to the producer, farm laborer, and nearby residential areas.

Housefly Life Cycle

The housefly has four stages of development - the egg, larva, pupa, and adult. The eggs are deposited in considerable numbers on decaying organic matter. Manure and wet feed around barns are excellent sources of organic matter for egg laying. A single female housefly may lay as many as 180 eggs at a time. The female will lay approximately five to six times during her lifetime (about 30 days) and may produce 1,000 eggs.

The young larvae emerge from the eggs within a day during normal summer temperatures. They feed in the manure for about 8 to 10 days before they are ready to pupate. The adults emerge from the pupa case in about 5 days. Thus, the cycle from eggs to adults takes about 10 to 15 days.

Fly breeding can occur for 200 days in Mississippi, depending on locality. During this time, a control program using residual sprays can be used in hog barns with animals present as long as water and food sources are protected. Resting places such as rafters, walls, and pen dividers should be sprayed. Insecticide baits should be placed in areas that pigs can not reach because most of these baits are sugar based and will be eaten by pigs.

Proper sanitation (destruction of breeding and feeding sites) is the most important part of fly control. Without good sanitation, all of your other efforts will be wasted. Damp or spilled feed should be cleaned from around bins. This material is a food source for flies and will hurt your use of chemical baits. Manure is an excellent breeding site for houseflies. However, if the moisture content is below 30 percent or if the manure is liquefied, fly breeding is almost nonexistent. Manure should not be allowed to collect in or around barns.

Control

The following materials are cleared for use on swine to control mites, lice, and for use around barns to control houseflies. For complete application instructions, be sure to read the label before mixing and using an insecticide. Remember, label information can be helpful in controlling pests and preventing hazards to you and your livestock. Note that several products will control both lice and mites.

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Publication 865
Extension Service of Mississippi State University, cooperating with U.S. Department of Agriculture. Published in furtherance of Acts of Congress, May 8 and June 30, 1914. Ronald A. Brown, Director

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