Brand: PROZAP ® VIP Insect Spray

Company: CHEM-TECH

FORMULATION: ready-to-use liquid for spraying cattle and their premises


  • Dichlorvos = DDVP = Vapona: 0.465% = 4.65 g/L
  • Pyrethrins: 0.025% = 0.25 g/L
  • Piperonyl butoxide (= PBO): 0.250% = 2.5 g/L

CHEMICAL CLASS of the active ingredient(s):


PARASITES CONTROLLED (spectrum of activity)


Beef & Dairy Cattle

  • Apply 1 to 2 ounces of VIP INSECT SPRAY to each animal. Cover the animal with spray paying particular attention to the back, flanks, legs, belly and shoulders. Do not use in excess of two (2) ounces per adult animal. Apply proportionately less to smaller animals. Do not soak the skin or wet the hide. Do not make direct application to livestock more frequently than once per day. Care should be taken that the spray does not come in direct contact with the lactating dairy cow’s teats unless they are washed with an approved cleansing solution and dried before milking. Brahman and Brahman cross cattle should not be treated as they may show hypersensitivity to organic phosphates.

Barns, Milk Rooms and Stables

  • When used as a space spray, close all doors and windows and direct the spray towards the upper portion of the enclosure until area is filled with a fine mist. Apply at the rate of one ounce spray per 1,000 cubic feet. If a coarse spray is used, apply wherever flies congregate or alight, until surfaces are moistened. The enclosure should remain closed for 10 to 20 minutes. Repeat as necessary, but no more than once per day. Do not remain in the treated areas and ventilate the area after treatment is complete. Do not use this solution for fogging or misting in areas where animals have received direct application of dichlorvos or other organophosphate within 8 hours. Do not contaminate water, feed or foodstuffs, milk or milking utensils.


  • LD50 (acute oral) in rats: >5000 mg/kg (according to MSDS) 
  • LD50 (acute dermal) in rats: >5000 mg/kg (according to MSDS) 
  • Estimated hazard class according to the WHO: U, unlikely to present acute hazard

Suspected poisoning? Read the article on dichlorvos = DDVP safety in this site.

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

  • Swine Meat: USA Do not ship swine for slaughter within 5 days of last treatment.
  • Milk for human consumption: USA NIL

WARNING !!!: Never use on humans, dogs or cats.

Dichlorvos and all organophosphates (e.g. coumaphos, diazinon, dichlorvos, phosmet, etc.) etc. are highly toxic to birds, fish and aquatic invertebrates. Do not apply directly to water, or to areas where surface water is present or to intertidal areas below the mean high water mark. Do not contaminate water when disposing of equipment wash-waters or rinsate.

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 houseflies and mosquitoes to pyrethroids (incl. natural pyrethrins) and organophosphates (incl. dichlorvos) is widespread in the USA and worldwide, and can be very high. Cases of resistance of gnats and stable flies have also been reported, but their prevalence is usually low.

The synergist in the formulation (PBO) is supposed to neutralize resistance of parasites to insecticides. However, PBO works only against the so-called metabolic resistance (enhanced detoxification) caused by mixed function oxidases (= MFO), which is one among several mechanisms by which parasites can become resistant to insecticides. PBO specifically inhibits the activity of MFOs. If metabolic resistance is caused by other enzymes than MFOs, or if resistance is (also) due to other mechanisms such as target site insensitivity, reduced penetration or behavioral modifications, it won't be neutralized by PBO. In the vast majority of cases producers or pet owners facing parasites resistant to synthetic pyrethroids do not know which mechanisms make the parasites resistant, and it is mostly not possible to find it out. Consequently, whether the synergist PBO helps to overcome resistance or not is in fact a lottery.

This means that if this product does not achieve the expected efficacy against the mentioned parasites, it may 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 for spraying, 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: USA
GENERIC BRANDS available? YES, perhaps not with this particular composition, but with a comparable one. This brand with generic dichlorvos and pyrethrins is marketed by CHEM-TECH in the USA.

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

For an overview on the most used antiparasitic spray, dip & dust BRANDS click here.


This product is one of the numerous liquid insecticides for spraying animals and/or premises for the control of flies other external parasites. Worldwide there are hundreds if not thousands of such products, mainly with synthetic pyrethroids ( e.g. permethrin) instead of natural pyrethrins. 

Insecticide liquids for spraying and dipping such as this product often represent the cheapest option for insect control on animals. However the active ingredients used in such products are mostly rather old (introduced in the 1950s to 1970s) and many pests have developed resistance to them. More modern and more effective active ingredients for the control of external parasites are often available only as ready-to-use pour-ons and injectables, or in the form of insecticide-impregnated ear-tags. They are usually more effective, more convenient and with a longer protection period than the liquids, but are also more expensive and often not approved for the control of as many pests as the concentrates.

Dichlorvos (also called DDVP or Vapona, its original brand) is a veteran broad-spectrum organophosphate introduced in the 1960s (by BAYER, CIBA-GEIGY, SHELL) that has been abundantly used worldwide in agriculture, public and domestic hygiene and in veterinary insecticides. It has the specific feature of being highly volatile. This makes it particularly appropriate for misting or fogging because it easily reaches flying insects (mosquitoes, flies, etc) and penetrates into cracks and crevices where many pests use to hide (e.g. cockroaches, beetles, etc.). Its volatility also favors fast penetration into the insect's body, which results in a rather quick knock-down effect. However, when applied directly to cattle, it quickly evaporates and consequently its residual effect is rather weak, i.e. protection against re-infestation is rather short, not longer than 2-3 days.

Pyrethrins are the natural relatives of the synthetic pyrethroids and share the insecticidal mechanism of action with them. Besides being natural instead of synthetic, their major difference is their volatility and the fact that they are quickly broken down by sunlight once applied to the animals' bodies or to any outdoor surface. For this reasons pyrethrins too offer not more than 1-2 days protection against fliesmosquitoes and other insects.

All organophosphates are veteran pesticides developed in the 1950s-1960s and are basically contact insecticides. Pyrethrins too are contact insecticides. This means that when the parasite comes in contact with them (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 (i.e. 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 animals, organophosphates and pyrethrins 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 organophosphates and pyrethrins 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 in meat and milk.

For best results it is very important to ensure a complete coverage of the animals' hair coat. This is best achieved after dipping the animals. Best alternative to dipping is high pressure spraying (depending on size and hair coat, adult cattle need 3 to up to 10 liters product for complete wetting). Efficacy after hand spraying or spot application are often poor due to the fact that using these methods some parts of the body may not be properly treated (e.g. inside the ears, below the tail, the udders, etc.), which allows a significant number of parasites to survive, reproduce and perpetuate the infestations. To learn more about spraying cattle and other livestock click here.

Control of susceptible (i.e. non-resistant) horn flies on cattle is usually good, because they spend a lot of time on cattle and thus are exposed to the insecticide for a long period of time. Lice are also exposed to insecticides for a long period of time because they never leave the host. Control of face flies is often not as good, due to their different behavior: they do not spend a lot of time on the animals and visit mainly body parts in the face that are humid with body fluids (eyes, nostrils, around the mouth), where the insecticide concentration is diluted by these body fluids. Stable flies, gnats, and mosquitoes may bite the treated animal anywhere in its body and remain attached and thus exposed to the insecticide only during their blood meals that last a few seconds or minutes, which is often too short to kill them. Trying to control populations of houseflies and other nuisance flies with on-animal topical products is usually ineffective. The simple reason is that they spend most of their time off-the animals.

Natural pyrethrins have a certain repellent effect, mainly on mosquitoes but it lasts usually only a few days, if at all.


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.