Winter lice controlWinter lice control

Unlike summertime vectors, you won’t hear the buzz of lice’s presence; however, you will see the impact they can have on your herd during wintertime.

Industry Voice by Neogen

January 16, 2025

4 Min Read
Wintertime cattle
Getty Images

“Lice are top of mind as temperatures start to drop in most areas,” says Nick Wagner, DVM, Professional Services Veterinarian with Neogen. “Lice complete their life cycle, including the developmental stages, entirely on the host animal and tend to be more prevalent during the year's cooler months.”
While lice can be present year-round, lice thrive during these winter and early spring months, due in part to the longer hair coats cattle have. “Lice populations often increase during the winter months due to the host animal’s hair providing additional insulation from cold temperatures," shares Warren Rusche, PhD, Assistant Professor and SDSU Extension Feedlot Specialist at South Dakota State University. “Management practices can also play a role in the increased incidence of lice during winter.” 


Understanding Lice and Implications on Herds 
The life cycle of lice can be completed in just days to weeks. Transmission is most common from animal to animal; however, it is possible to spread through other sources, such as grooming equipment (an important reminder come livestock show season). Cattle are affected by both chewing lice and sucking lice; both can impact cattle across the world. Five species of lice are found on cattle in North America: short-nosed cattle lice, long-nosed cattle lice, little blue cattle lice, cattle tail lice, and biting lice. “The chewing lice consume hair and scaling skin whereas the sucking lice consume blood,” shares Dr. Wagner. “Lice can be present on the skin surface at the base of the hair; they also have a predilection for the face, neck, shoulders, back, and tailhead of the animal.”
Lice causes irritation, itching, and crusting of the skin as well as hair loss, resulting in detrimental impacts on performance and health, with heightened risk for disease challenges due to heavy infestations and blood loss. “If the disruptive nature of these pests results in variations in the nutritional intake patterns of growing cattle, this could significantly impact daily gains and increase their susceptibility to disease. Therefore, it is quite evident the significant impact that this can have on the profitability of your herd,” says Dr. Wagner. 
With implications on both health and rate of gain, the University of Nebraska and other studies indicate heavy lice populations may reduce weight gains by as much as 0.21 lb./day.

Related:Audits, certification provide assurances


3 Lice Control Best Practices for Success

  1. Keep active ingredients and mode of action at the forefront when considering insecticide options. When selecting an insecticide, consideration should be given to the active ingredients and their mode of action. Further, it is important to also consider that insecticide resistance may be present in ectoparasite populations in various geographic locations. Therefore, a chemical control strategy that rotates between classes of insecticides is recommended. Selecting a formula that includes an insect growth regulator (IGR), such as diflubenzuron, will also kill louse eggs before they hatch, minimizing handling, time, and labor costs.

  2. Follow treatment protocols and ensure proper dosage. Work with your veterinarian to help you develop an effective lice and insect control program for your operation. “It is critically important to follow treatment procedures closely to maximize treatment effectiveness against lice,” Rusche says. Additionally, keep in mind the importance of proper dosage and read product labels thoroughly. “Regardless of product choice, the dosage must be adequate for the size of the animal being treated. Under-dosing could result in insufficient control and cause other animals in the group to be re-infested,” adds Rusche.

  3. Consider cold weather syringeability to make administration easier and more effective. Colder weather can impact how easily or difficult an insecticide can be syringed or dispensed. This can cost producers additional time spent on labor and increases the chance of under-dosing. Choosing a formulation with proven cold-weather syringeability and an easy-to-use syringe is key for your operation. Products such as Prozap® Protectus™ Pour-On Insecticide—IGR along with the Prozap 30 mL Pour-On Applicator have proven to be 36% easier to squeeze in below-zero temperatures and can refill up to seven times faster than the market-leading pour-on with IGR.

Related:Elanco launches novel treatment for livestock respiratory diseases

“With a better understanding of the common ectoparasites that target cattle, producers can develop and implement effective integrated pest management control programs specific to their operations to protect those hard-earned assets,” encouraged Dr. Wagner. “Dedicating the necessary attention to ectoparasite control will pay dividends.”

Related:Elanco launches novel treatment for livestock respiratory diseases

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