Two or more species of cattle lice often occupy the same animal. However, an animal with many sucking lice usually has only a low or moderate number of biting lice, and vice versa.

Louse-lnduced Anemia
     Several studies have documented severe anemia in cattle as a result of shortnosed sucking louse infestations. Anemic cattle fail to gain weight, or they may slowly lose weight. They appear very weak and have extremely pale skin around the eyes, muzzle, and udder. Their red blood cells may be reduced to as little as one-half or one-fourth the normal number. Extreme louse-induced anemia causes pregnant heifers and cows to abort. Anemic cattle have low resistance to diseases and to stresses caused by bad weather, shipping, or handling. Such cattle become very exhausted and may die if forced to move even 100 to 300 yards.

     Ridding anemic cattle of lice usually results in rapid improvement. Complete recovery may be achieved within a month. However, in ridding such cattle of lice one should remember that they must be handled gently and may not be able to withstand the stress of dipping or of crowding in holding pens while sprays are applied. Weakened animals are also more readily poisoned by insecticides, especially those with systemic action.

Controlling Cattle Lice
     Sanitation. The primary way in which lice are spread is from animal to animal when cattle are in close contact with one another such as during feeding, breeding, or shipping. However, some lice and louse eggs drop off into bedding or are rubbed off, along with hair, onto fences and feedbunks. These die in a few hours in cold weather; but in warm weather the lice may live for several days if not exposed to direct sunlight, and some of the eggs may hatch. Other cattle may then become infested from contaminated bedding, bunks, sheds, or trucks. For this reason, premises vacated by infested stock should either be disinfected or should stand empty for 10 days before being used by clean stock.

     Newly purchased stock should be isolated and treated for lice before being added to the herd.

Chemical Controls
     Herds routinely treated against cattle grubs, ticks, horn flies, or face flies, may not develop louse infestations which warrant treatment. When cattle are to be treated for lice, it is important to consider what other insecticides or medications have been, are being, or will be used on the same animals. Multiple treatments or combined effects of different treatments may cause toxic reactions in livestock. This is especially true of the organophosphates with systemic action, which are popular in grub control programs. If grubby cattle are to be treated for lice or other pests, it is wise to do one of the following: 1 ) treat early in the fall with timing and insecticide selected to kill the cattle grubs also, or 2) if it is after the safe date for using systemic insecticides against grubs, use only a nonsystemic insecticide against the lice.