The eight-legged white or yellow mange mite, Scarcoptes scabei, spends its entire life cycle on the hog. This microscopic mite digs beneath the skin, creating slender winding tunnels nearly one inch long throughout the infested part of the body. The parasite dissolves the animal's tissue with its strong digestive enzymes and then sucks up this liquid. The female mite deposits eggs in the channel that she builds while feeding. Eggs hatch in 3 to 10 days, and a generation can be completed in only 2 weeks.
Areas around eyes, ears, back, and neck are most often affected. The hide becomes thick, rough, red, and pimply. The hair stands erect, and scabs may appear on the hide, especially in or near the ears. Secondary infection by bacteria may occur where the mites have burrowed. The hide of baby pigs becomes red and rough. If you see hogs scratching vigorously but you cannot find lice on them, they are probably infested with mange mites. To make a positive identification, use a knife to scrape the infested skin surface until bleeding begins. Examine these scrapings under a magnifying glass on a dark surface. You will see the tiny mites scurrying about, if they are present.
Although some mange mites are present year round, cooler fall and winter weather appears to promote mite reproduction. Animals in enclosed, warm buildings during winter generally have fewer mange problems.
Packing companies report that a mange-infested animal must be skinned on the killing floor, and that the hide cannot be processed for pigskin leather. The carcass must sell at a discount. The reduced weight gain and lowered feed efficiency that occur in mangeinfested hogs are very difficult to measure. Suckling pigs infested with mange often develop into runts.
The following program will help prevent lice and mite infestations. Because new boars, sows, or feeder pigs added to your herd may carry mites, lice, or their eggs, you should treat all hogs that are added to your herd before they come in contact with your animals. A good time to stop lice and mange is when the sows are being readied for farrowing, even though mange or lice symptoms may not be evident. If the lice and mites are controlled on the sows, they will not have a chance to move to the young pigs. This is important, since a mange infestation on baby pigs spreads rapidly, and baby pigs should not be treated with most pesticides.
If an outbreak of lice or mange is detected in your herd, treat the entire herd, even though certain individuals may appear parasite-free. Pesticide sprays recommended for control of mange or hog lice are more effective when applied at the rate of 2 to 4 quarts of finished spray per animal using high-pressure sprayers. Spray small numbers of the animals at one time and give thorough coverage with special emphasis to the head, neck, and ears. A nonfoaming detergent (0.25 lb per 25-gal spray) may be added to the spray to help maintain coverage. If cold winter weather prevents the use of sprays for treating mange or louse-infested hogs, dusts and bedding treatments are available that give varying degrees of control.