Each winter we field a number of enquiries about cattle lice, so this article aims to supplement some of the advice we provide.
There are two main types of cattle lice; biting lice (Bovicola bovis) and sucking lice (Linognathus vituli). Both types are irritating for the cattle, making them ‘rubby’ and causing damage to trees, fences and infrastructure. It’s important to identify if you have a biting or sucking lice infestation, in order to choose the most suitable product for treatment.
Biting Lice vs Sucking Cattle Lice
Biting lice feed on skin scurf, skin cells and bacteria that lives on the skin of the cattle. They are approx.. 2mm long with a reddish-brown body and brown head (Figure 1). Biting lice are mainly found on the neck, shoulders, back and rump of the animal.
The entire life cycle of biting lice takes around 30 days, from egg to adult. Each female will lay around 30-35 eggs and adult biting lice live for 9-10 weeks.
There are a few different species of sucking lice, however, they all have means of piercing the skin of the cattle to feed on blood. The most common species is the long-nosed sucking louse. They are approx. 2.5mm long, with a bluish-black body and a pointy, black head (Figure 2). Other sucking lice species vary in shape, colour and size, but all of them have a pointy head segment that facilitates feeding on blood.
The life cycle of long nosed sucking lice is slightly shorter than biting lice, taking about 29 days from egg to adult. Adults live for around 42 days, with females laying up to 50 eggs.
All lice are more active in cooler conditions, when the cattle have longer coats.
Treating Cattle Lice
Cattle won’t always need treatment for lice infestations, as light infestations don’t usually reduce growth rates. If you find you have a small infestation at the end of winter, they often go away once the cattle cut their summer coats in spring. Occasionally treatment will be required depending on the percentage of the mob affected and the severity of their rubbing. Especially when you want the cattle looking pristine for sale or shows.
Step 1 is to determine (as best as you can) if the louse on your herd are sucking or biting lice.
Step 2 is to treat 100% of the mob, using the most appropriate product. It is important that the entire mob is treated and the treatment is applied thoroughly.
- If they are biting lice, a pour-on treatment will be most effective. For example, Vetmec Pour-On or other synthetic pyrethroids, organophosphates or insect growth regulators.
- If they are sucking lice, a pour-on or injectable treatment will be effective. For example, Vetmec Antiparasitic Injection, Vetmec F Injection and Vetmec LA Long Acting Cattle Injection.
Step 3 involves checking the cattle 2-4 weeks after treatment to ensure a good kill of lice on the cattle that are most severely infected (‘lice taxis’). It can be worth re-treating these cattle, 4-5 weeks after their initial treatment.
As lice are more active in winter, it is strategic to treat relatively soon after the cattle have grown their winter coats. This way, the lice are out of their summer hiding places but they haven’t had time to build their numbers up to a severe infection. The late autumn/early winter treatment is likely to coincide with a drench for worms. Check the label of the product you are drenching with, as it will likely also treat lice.
If you would like to chat more about anything in this article, or have any other parasite management questions, feel free to give us a call on 1800 243 683.
Products Mentioned in this Article
Other References
Suck? Or Bite? It Makes a Big Difference for Cattle Lice | Paraboss
Cattle Biting Louse | Liceboss
Long-nosed Sucking Louse | Liceboss
Lice Infestations on Cattle | PIRD WA
Lice | MLA
Treating Lice in Cattle: When, How and What Chemical Group | Liceboss