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Feb 24, 2016
Cattle LiceLiceLice populations build up on cattle in the winter months, and are mainly a problem from November through March. Lice are not a problem on cattle in the summer months because they are not able to tolerate warmer temperatures in populations high enough to cause noticeable symptoms. Cattle with lice infestations will scratch off their hair in affected areas and lick these areas because of irritation. Cattle can be examined for the presence of lice in a squeeze chute by parting the hair on the face, brisket, shoulders, hips and tail head.
LiceCattle spread lice from one another by close contact and grooming. If control is implemented, all the animals in the herd must be treated. Ringworm and scabies may also present symptoms similar to lice infestations, so cattlemen should check carefully before treating. If in doubt, consult your veterinarian.Lice have gradual metamorphosis, which consists of eggs, nymphs and adults. Lice must spend their entire life cycle on the host animal, meaning the eggs, 3 nymphal instars, and adults are all present on the animal at the same time. Lice can go from the egg stage to the adult stage in as little as 16 days, depending on the species.
Biting Lice The cattle biting louse does not actually bite the animal. Biting lice feed on organic matter on the surface of the skin. Just the presence of the louse causes general irritation which causes the animal to scratch and rub.
Sucking Lice There are three main species of sucking lice. These three species are the short nosed cattle louse, the long nosed cattle louse and the little blue louse. All sucking lice have piercing sucking mouthparts and pierce the skin and take blood from the animal. All three nymphal stages as well as the males and females suck blood.Cattle appear greasy when infested with sucking lice
Detecting lice infestationsLice should be suspected when cattle show signs of rubbing. Rubbing causes hair loss on the neck, shoulders and rump and needs to be differentiated from the normal appearance of the seasonal shedding of the winter coat. To detect lice, run cattle through a chute and examine the skin by parting the hair. Good lighting and a magnifying glass will help you see the lice as they attempt to move away from direct sunlight. Biting lice of cattle are recognized by a rounded head, light brown color and high mobility as they move when the hair is parted. Sucking lice are grey or blue grey and have a pointed head that tends to remain fixed to the skin. You may also see eggs, which are white and cemented to the shafts of coat hairs in clumps.
Lice Control A second treatment for lice control must be made 2 to 3 weeks after the initial treatment because the developing eggs present at the time of initial treatment will hatch and the residual pesticide will likely not be of a concentration high enough to kill the newly emerging nymphs.
Sucking Cattle Lice (NC State W. Watson)Severe lice infested animal. (Angus Beef Bulletin; L. Townsend Univ. of Kentucky)