In temperate climates, domestic cattle may be infested with one species of chewing louse (Bovicola [formerly Damalinia] bovis) and four species of bloodsucking lice (Linognathus vituli, Solenopotes capillatus, Haematopinus eurysternus, and Haematopinus quadripertusus). Except for H quadripertusus, these lice have a cosmopolitan distribution; ie, they are found throughout most of the world.
H quadripertusus, the cattle tail louse, is a tropical louse that has extended its distribution into subtropical areas. In the US, H quadripertusus has been reported in California, in Florida, and in other Gulf Coast states. The cattle tail louse is known to parasitize both European and Zebu breeds of cattle. In addition, Haematopinus tuberculatus, the buffalo louse, can be found occasionally on domestic cattle in tropical regions where they are in contact with buffalo.
Whereas most lice are transmitted via direct contact between animals, H quadripertusus can also be transmitted by the horn fly, Haematobia irritans.
Lice infestations tend to be heaviest in the winter, decreasing greatly as summer approaches. Cattle, especially young animals, may be infested with multiple species of lice simultaneously. S capillatus and H eurysternus infestations are more often recognized on mature animals, whereas L vituli is more common on calves and on dairy cattle.
For cattle of all ages, stressors such as high stocking density, poor feed quality, gestational status, and underlying health problems often contribute to the susceptibility and extent of infestation. For the predilection sites on the host and a general description of each species, see the table General Descriptions and Predilection Sites of Cattle Lice General Descriptions and Predilection Sites of Cattle Lice .
Pathogenesis and Disease Transmission of Lice in Cattle
Pediculosis in cattle can decrease weight gain and milk production, lead to weight loss, and damage hide and hair. Reduction in daily weight gain is common in cattle moderately to heavily infested with lice. In dairy herds, the juveniles, dry cows, and bulls may escape early diagnosis and suffer more severely. Young calves may die, and pregnant cows may abort.
L vituli can serve as a mechanical vector for Anaplasma marginale, the causative agent of bovine anaplasmosis Anaplasmosis in Ruminants Anaplasmosis is a tickborne disease of ruminants caused by intracellular bacteria that infect red blood cells, causing fever and anemia. Diagnosis relies upon Giemsa-stained blood smears and... read more .
Outside the US, H eurysternus populations have been found to contain multiple Rickettsia spp; however, the role that lice play in transmitting rickettsial agents is not well understood.
In Australia, H eurysternus also has been identified as having a potential role in mechanical transmission of the parasite Theileria orientalis, and in Israel, Bartonella sppbacteria have been identified in H quadripertusus.
Treatment of Lice in Cattle
Administration of pour-on and injectable macrocyclic lactones and pour-on pyrethroids
Adjustment of husbandry practices to minimize infestations
A variety of compounds effectively control lice in cattle, including the following:
In beef cattle only: synergized pyrethrins; also the synthetic pyrethroids cyfluthrin, permethrin, zeta-cypermethrin, and cyhalothrin (including gamma- and lambda-cyhalothrin)
In beef and nonlactating dairy cattle only: the organophosphates phosmet and chlorpyrifos; also tetrachlorvinphos, coumaphos, and diazinon
In all cattle: the macrocyclic lactones moxidectin, ivermectin, eprinomectin, and doramectin
Pour-on formulations are effective against biting and bloodsucking lice. Injectable formulations are effective primarily against bloodsucking lice.
Because application is easy and less stressful for the treated animal, the pour-on method has become a popular way to apply insecticides. Self-treatment devices also can be used, such as back rubbers, oilers, dust bags, and ear tags. Cattle dips have fallen out of favor in the US because of the labor-intensive nature of the process and the amount of chemical needed to keep vats charged with active compound.
The compound chosen must be appropriate for the animal's age, reproductive status, and production system. The treatment of meat and dairy animals must be restricted to uses specified on the product label, and all label precautions should be carefully observed. Appropriate meat and milk withdrawal times must be observed. In most countries, regulatory agencies specify tissue residue limits of insecticides and carefully regulate insecticide use on production animals. All regulations are subject to change, and pertinent current local laws and requirements should be determined before treatment.
Multiple pour-on formulations of 5% permethrin/5% piperonyl butoxide, 5% diflubenzuron/5% permethrin, and gamma-cyhalothrin are labeled for season-long control of lice (~3–4 months) on beef and dairy cattle. However, decreased efficacy of pyrethroids has been reported in various locations worldwide.
Although both amitraz and spinosad are effective against lice, both drugs have been removed from the US market since 2014.
Certain Brahman and Brahman-cross cattle have organophosphate hypersensitivity, which should be considered when selecting a treatment compound.
Husbandry problems (overcrowding, poor feed quality, etc) and underlying health conditions in animals should be addressed. Treatment is the most effective if trailers, chutes, and other areas that cattle have contacted are cleaned and treated with an appropriate premise spray.
Lice can have a substantial impact on cattle production.
Infestations may lead to a poor coat, pruritus, and dermal irritation.
Many effective treatments are available; however, they can differ for chewing and sucking lice
Control and prevention must also address overcrowding, poor husbandry, and underlying conditions that lead to heavier lice infestations.