Insecticide-Impregnated Cattle Ear Tags

Cattle receiving insecticide-impregnated ear tags take their fly control system with them. Ear tags have provided a popular option to control the horn fly, a blood-sucking insect that hits producers with a $1 billion bill for losses and control costs each year. In addition, the tags can reduce face fly numbers on cattle.

The plastic ear tags (Figure 1) release small amounts of an insecticide that is distributed over animals during grooming, rubbing, or in skin oils. The approach is very effective against horn flies because these insects are rarely off animals.  Unfortunately, this almost constant exposure has resulted in development of insecticide-resistant horn flies in some areas. This results in reduced control or a shorter control period than seen previously.

Figure 1. Applying an ear tag (Source unknown)

Rotation has been the main strategy in managing insecticide resistance in horn flies. This entails selecting insecticides with different modes of action. Insecticide-impregnated cattle ear tags fall into four main groups based on the mode of action groups that they contain. Seasonal rotation between these groups can be useful in combating insecticide resistance. It is important to check active ingredient names on product labels because most options (pour-ons, sprays, dusts, etc.) belong to either Group 1b or Group 3. Rotation based on different brand names does not mean changing a mode of action group.

  • Group 1b (organophosphate) insecticides in tags include chlorpyrifos, coumaphos, diazinon, or Pirimifos‐methyl.
  • Group 3 (pyrethroid) insecticide active ingredients include b-cyfluthrin, l‐cyhalothrin, z‐Cypermethrin, and permethrin. Some pyrethroid tags contain piperonyl butoxide (PBO). This is a synergist. It does not kill insects but stops the enzymes in certain insects that break down some insecticides. PBO in a formulation can increase pest control.
  • Group 6 active ingredient abamectin
  • A combination tag that includes an active ingredient from Group 1b and one from Group 6

Safety Precautions When Using Insecticide Ear Tags

Insecticides in cattle ear tags can be absorbed through the skin and may cause eye irritation. Do not handle insecticide-impregnated ear tags barehanded. The percentage of active ingredient in some tags can be up to 40%. The tags are formulated to release insecticide so it is easily transferred to the animal’s coat. Check the signal word on the product label (Table 1). They range from Caution to Danger. Use the protective equipment listed in the Directions for Use section of the pesticide label. Most require 14-mil thick rubber, non-permeable, or chemical-resistant waterproof gloves. Double Barrel and Dominator tags require protective eye-wear. Always disinfect tag pliers prior to use.

Table 1. Brand names, modes of action, and signal words of selected insecticide impregnated ear tags.

Brand name

(tag weight)

Active ingredients

(mode of action group )

Signal Word

Cylence Ultra 8% cyfluthrin +  20% PBO  (3) Caution
Python Magnum

(15.4 gms)

10% z-cypermethrin + 20% PBO (3) Caution
Saber Extra

(9.5 gms)

10% l-cyhalothrin + 13% PBO (3) Caution
Double Barrel VP

(9.5 gms)

6.8% l-cyhalothrin +

14% pyrimofos-methyl (3)


(14 gms)

15% Coumaphos +

35% diazinon  (1)


(15 gms)

21.4% diazinon (1) Warning

(15 gms)

40% diazinon  (1) Warning

(15 gms)

30% diazinon +

10% chlorpyrifos (1)


(9.5 gms)

20% pirimifos‐methyl (1)


XP 820 Abamectin  (6) Caution

Number of Tags Per Head

Most products list one or two tags per animal, depending upon the target pest or desired level of fly control. Several give the option of two tags for optimum fly control or one for adequate control. Patriot and Warrior tags state one tag per calf. Cylence Ultra prohibits tags for animals less than 3 months old. Ear tag weights in grams are provided when available; they range from 9.5 to 15 grams. Place tags carefully to maximize retention.


By Lee Townsend, Extension Entomologist


Posted in Livestock Pests