Controlling external parasites on cattle
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EmailConsult with your veterinarian to develop a systemic plan for the responsible control of external parasites such as ticks, flies and lice in your cattle herd.
External parasites that feed on the blood of cattle, including flies, ticks and lice, pose a serious threat to cattle health due to the possible transmission of various pathogens that can negatively impact animal well-being and reduce growth and reproductive performance. Controlling these parasites in your herd will help keep your herd healthy and improve their well-being.
Flies
There are several types of flies associated with annoying and stressing cattle, including horn flies, stable flies, house flies, heel flies, horse flies and deer flies. Fly season in the upper Midwest begins in the spring months (March–May) as the temperatures begin to warm up. The stress caused by flies can lead to reduced weight gain and milk production of impacted cattle. Face flies can cause eye irritation and spread pinkeye (Moraxella bovis) between cattle. Additionally, biting flies can cause skin irritation, hide damage and the spread of various blood-borne diseases. Some flies can lead to fly strike, where flies infiltrate wounds and deposit eggs for the hatched maggots to feed on once hatched. However, a majority of fly species lay eggs in the manure of cattle. Depending on the fly species, it can take from half a week to three weeks to complete the life cycle from egg to adult.
Lice
There are a couple species of lice that can be bothersome to cattle. Among lice, there are biting or sucking lice depending on the morphology of their mouth and what they choose to feed on (i.e., blood, skin, hair). Animals affected by lice appear less thrifty and can suffer from reduced performance and anemia as well. These affected cattle display signs of itching or may be missing patches of hair from scratching. Lice infestations are most common in late fall through the spring and typically decline in the summer.
Ticks
Ticks are most active during spring, summer and fall. In many states, they are able to survive winter temperatures. There are many different species of ticks that can feed on and negatively impact cattle. In the U.S. the American dog tick, Asian longhorned tick, Blacklegged (deer) tick, Lone star tick, Gulf coast tick and Rocky Mountain wood tick are present and could be possible pests for cattle. Most ticks are three-host ticks, meaning ticks in the larva, nymph and adult stage fall off the host after consuming a blood meal for a couple days, with the exception of cattle fever ticks, which are single-host ticks. Fed adult females can lay up to a few thousand eggs at a time, leading to large infestations. Due to the blood consuming nature of these pests, they can be a vector of disease transmission to cattle.
Disease
Some diseases spread by ticks to cattle in the U.S. are Anaplasmosis (Anaplasma marginale), Theileriosis (Theileria orientalis) and Lyme borreliosis (Borrelia burgdorferi), however, Babesiosis (Babesia spp.) and Ehrlichiosis (Ehrlichia ruminantium) are diseases of concern for cattle in other parts of the world. Anaplasmosis is caused by a bacterial blood cell parasite that can cause symptoms of fever, weight loss, decreased milk production, abortion, anemia and possibly death. Anaplasmosis is commonly treated with antibiotics such as tetracyclines, however, cattle will remain carriers after treatment. Cattle with Theileriosis display similar symptoms to those caused by Anaplasmosis. Theileriosis is caused by the protozoan infection of red and white blood cells which leads to anemia. In severe cases of anemia, cattle may require a blood transfusion. After experiencing an acute reaction to the disease, the host (cattle) will develop antibodies to the disease while remaining a carrier of the disease.
External parasite control
Among the approved insecticide products for cattle, they may have one of four different modes of action to control external parasites. A rotation of use between these different active ingredients and modes of action can improve their efficacy and minimize the development of resistance.
- Organophosphates (class 1B – acetylcholinesterase inhibitors) – diazinon, tetrachlorvinphos, coumaphos, phosmet, naled, pirimiphosmethyl, chlorpyrifos
- Pyrethroids and Pyrethrins (class 3A – sodium channel modulators) – permethrin, cypermethrin, cyfluthrin, lambda amd gamma-cyhalothrin
- Avermectins and Milbemycins - Macrocyclic lactones and macrolides (class 6 – glutamate-gated chloride channel allosteric modulators) – abamectin, doramectin, eprinomectin, ivermectin, moxidectin.
- Insect growth regulators (IGR):
- Juvenile hormone analogues (class 7A – Juvenile hormone receptor modulators) – Methoprene
- Benzoylureas (class 15 – inhibitors of chitin biosynthesis affecting CHS1) – diflubenzuron
These insecticides can be used through various applications to offer protection from external parasites. There are numerous livestock insecticide sprays commercially available on the market that can be dispensed in a barn or on animals to provide external parasite control. As their name indicates, pour-on products are applied over the back of the animal to offer extended protection. Likewise, injectable insecticide products offer extended protection and are delivered in the injection triangle of the animal’s neck. Insecticide ear tags offer protection around the head of the animal, but their delivery works to distribute the insecticide on other animals in the herd as they rub against each other. Other forms of insecticide delivery can be through the use of back rubbers, scratching posts and oilers to dispense a mixture of insecticide and diesel or mineral oil on cattle near loafing areas (i.e., mineral feeder, lick tub, water). Some of these products are listed below by their active ingredients’ mode of action classification.
- Pour-on
- Class 3A products: Boss (Merck), Ultra Boss (Merck), Saber (Merck), Ultra Saber (Merck), Synergized Delice (Merck), Clean-Up II (Elanco), Permectrin CDS (Elanco), CyLence (Elanco), Brute (Y-Tex)
- Class 6 products: Cydectin (Elanco), Eprizero (Nalbrook), Eprinex (Boehringer-Ingelheim), Ivomec (Boehringer-Ingelheim), Dectomax (Zoetis), Parmectin (Zoetis)
- Injectable
- Class 3A products: Cydectin (Elanco), LongRange (Boehringer-Ingelheim), Ivomec (Boehringer-Ingelheim), Dectomax (Zoetis), Valcor (Zoetis)
- Insecticide ear tag
- Class 1B products: Dominator (Merck), Double Barrel VP (Merck), Corathon (Elanco), Patriot (Elanco), Max 40 (Y-Tex), Tri-Zap (Y-Tex), Optimizer (Y-Tex)
- Class 3A products: Saber Extra (Merck), Double Barrel VP (Merck), CyLence Ultra (Elanco), Tri-Zap (Y-Tex), PYthon II (Y-Tex), PYthon II Magnum (Y-Tex), GardStar (Y-Tex)
- Class 6 products: XP 820 (Y-Tex)
Larvicides are insecticides that disrupt the larval stage of the insect preventing them from becoming functional adults. In feedthrough products, these insect growth regulators (IGR) are designed to be ingested, not digested by the animal and excreted in the manure to disrupt the development of the larva that hatch from the eggs in the manure of cattle. Some examples of feedthrough IGR products include: ClariFly Larvicide, JustiFly Feedthrough, Rabon Oral Larvicide, Neporex 2SG, IGR Cattle Concentrate, and Altosid IGR. Some of these products are available in premixes, lick tubs, or mineral blocks. There are also larvicide sprays that can be applied to manure piles to help control flies.
It is important to carefully read and follow all label instructions regarding dosage, route of administration and possible withdrawal times. Rotating insecticide products with different modes of action to prevent insecticide resistance development in the prevalent external parasites being controlled. Carefully consider the timing and route of insecticide application based on your external parasite pressure and cattle processing schedule throughout the year to further prevent insecticide resistance development. Reference to commercial products or trade names does not imply endorsement by MSU Extension or bias against those not mentioned
If you have concerns with external parasites in your cattle or would like to discuss this topic further, reach out to me or one of the other Michigan State University Extension beef team members. We would be happy to talk about developing or revising a plan to control external parasites in your cattle herd. We also recommend that you discuss all herd health-related issues with your veterinarian to maintain a good client-patient relationship.
Other great resources
Insect Control for Beef Cattle - University of Kentucky
Common Flies of Cattle - University of Kentucky
Treatment Guidelines for Cattle Lice - University of Kentucky
