Brand: VANQUISH ® Long Wool

Company: COOPERS

FORMULATION: ready-to-use «spray-on» for topical administration as a single strip along the backline.

ACTIVE INGREDIENT(S): alpha-cypermethrin: 5% = 50 g/L

CHEMICAL CLASS of the active ingredient(s): synthetic pyrethroids


PARASITES CONTROLLED (spectrum of activity)

RECOMMENDED DOSE & use instructions*


Animal Pest Wool Growth Months since Shearing
Dose Volume mL Critical Comments

Adult Sheep and Shorn Lambs

Body lice (Bovicola = Damalinia ovis) Less than 4 months 10 mL Apply the product along the backline of sheep ensuring equal deposit on each side of backline.

The spray band should be approx. 12 cm in width.

Reduced effectiveness is likely if used on sheep with lumpy wool.

Over 4 months 20 mL

Unshorn Lambs

Body lice (Bovicola = Damalinia ovis) Less than 2 months 5 mL
2-6 months 10 mL
Over 6 month 20 mL

All sheep

Blowfly (Lucilia cuprina)
2-10 months 20 mL

 * May not be the same in all countries

Read the complete product label carefully and ensure thorough accomplishment of all the use instructions.


  • LD50 (acute oral) in rats: for the a.i. 250 mg/kg (in corn oil) to 4123 mg/kg in water (according to MSDS)
  • LD50 (acute dermal) in rats: for the a.i. 1600 mg/kg (according to MSDS)
  • Estimated hazard class of the product according to the WHO: III, slightly hazardous

Suspected poisoning? Read the article on cypermethrin safety in this site.

Withholding periods (=withdrawal times) in days for meat & milk (country-specific differences may apply: read the product label)

  • Meat:
    • Australia: NIL (0 days) (ESI = 7 days)
    • New Zealand: 7 days
  • Milk for human consumption:
    • Australia: DO NOT USE on female sheep which are producing or may in the future produce milk or milk products for human consumption
    • New Zealand: 35 days
  • Wool: Australia & New Zealand: 2 months

WARNING !!!: Never use on humans, dogs or cats. Synthetic pyrethroids are toxic to cats!

2nd-generation synthetic pyrethroids (e.g. cyhalothrin, cypermethrin, deltamethrin, permethrin, etc.) are irritant to the eyes and the skin, both of humans and livestock. The inert ingredients in the formulation may worsen this side effect. Irritation can be particularly problematic for dairy cows because it can significantly hinder handling for milking.

You may be interested in the following articles in this site dealing with the general safety of veterinary products:


Risk of resistance? YES, resistance of body body lice (Bovicola ovis) to synthetic pyrethroids (incl. alpha-cypermethrin) is widespread in Australia, and can be very high. It has also been reported in New Zealand.

This means that if this product does not achieve the expected efficacy against the mentioned parasites, it can be due to resistance and not to incorrect use, which is usually the most frequent cause of product failure.

Alternative chemical classes/active ingredients to prevent resistance of external parasites through product rotation:

These alternative products may not be available in all countries, or may not be available as ready-to-use spray-ons, or may not be effective against all the concerned parasites.

Learn more about resistance and how it develops.


Are the active ingredients of this product ORIGINAL* or GENERICS**?


*Meaning that they are still patent protected and generics are not yet available
**Meaning that they have lost patent protection and may be acquired from manufacturers of generic active ingredients other than the holder of the original patent.

COUNTRIES where this brand/product is marketed: Australia, New Zealand
GENERIC BRANDS available? YES, but maybe not with the same indications.

Click here to learn more about GENERIC vs. ORIGINAL drugs.

For an overview on the most used antiparasitic pour-on brands click here.


VANQUISH Spray-on for sheep is one of the few products with a synthetic pyrethroid still marketed for the control of body lice and blowfly strike prevention in Australia. The reason is that body lice has developed high resistance to synthetic pyrethroids in numerous regions, and that protection against blowfly strike (about 6 weeks) is much shorter than for numerous alternative products. 

Cypermethrin is one of several Type-II synthetic pyrethroids introduced by ICI & SHELL in the 1970s. Worldwide it is massively used in veterinary products as well as in agricultural and hygiene pesticides. Alpha-cypermethrin is one of several standard isomer mixtures of cypermethrin (see below).

All synthetic pyrethroids are veteran pesticides developed in the 1970s-1980s and are basically contact insecticides. This means that when the parasite comes in contact with it (e.g., during the blood meal, after landing on a treated host, etc), the active ingredient that impregnates the host's hair coat penetrates through the cuticle of the parasite (the "skin" of insects and other arthropods) into its organism and disturbs essential biological processes in the parasite's body, in this case its nervous system.

After administration to livestock or other mammals, synthetic pyrethroids do not have a systemic mode of action, i.e. they are not transmitted to the parasite through the blood or the host. Topically administered synthetic pyrethroids are very poorly absorbed through the skin of the hosts, and what is absorbed is quickly broken down and/or excreted. Consequently the concentration reached in the blood is too low to kill blood-sucking parasites. But this is why they are considered rather safe for mammals, both humans and livestock (cats are an exception: pyrethroids are toxic to them!) and why they leave rather low residues.

All ready-to-use pour-ons and spray-ons containing contact insecticides such as synthetic pyrethroids have the same weakness: they are applied on the back of the animal and spread more or less quickly along the hair coat to other parts of the body, but coverage is usually not homogeneous and some parts of the body are not or only poorly reached. How fast and complete the spreading is depends on a lot of factors (e.g. distance to the delivery point, rain, animal behavior such as grooming, licking, rubbing, etc.) but also on the inert ingredients in the formulation, which may or may not favor spreading. In any case, compared with the backline the concentration of the active ingredient will be significantly lower in body parts that are difficult to reach (e.g. udders, perineum, below the tail, inside the ears, etc), where some parasites may survive because the concentration is not high enough to kill them. Irregular spreading may also cause chronic exposure of some parasites to sub-lethal doses, which is known to favor development of resistance.

It is useful to know that the active ingredients of many synthetic pyrethroids consist in a mixture of various optical isomers, typically those called "cis", and those called "trans". The efficacy against parasites and the mammalian toxicity of these isomers are significantly different. Typically cis isomers are more effective insecticides but also more toxic to mammals. Obviously a cis/trans 80/20 mixture is more potent than a cis/trans 40/60 mixture. Cypermethrin has 8 isomers, 4 cis and 4 trans. Manufacturers of active ingredients usually supply the raw material in standard qualities, for cypermethrin typically e.g. in a 40/60 or 80/20 cis/trans ratio. Alpha-cypermethrin is a mixture of only 2 cis isomers, i.e. it is a 100% cis mixture.


This article IS NOT A PRODUCT LABEL. It offers complementary information that may be useful to veterinary professionals and users that are not familiar with veterinary antiparasitics. 

Information offered in this article has been extracted from publications issued by manufacturers, government agencies (e.g. EMEA, FDA, USDA, etc.) or in the scientific literature. No guarantee is given on its accuracy, integrity, sufficiency, actuality and opportunity, and any liability is denied. Read the site's DISCLAIMER.

In case of doubt contact the manufacturer or a veterinary professional.