Brand: BUTOX SWISH Pour-on
Company: MERCK ANIMAL HEALTH
FORMULATION: «pour-on» for topical administration.
ACTIVE INGREDIENT(S): Deltamethrin: 0.75% = 7.5 g/L
CHEMICAL CLASS of the active ingredient(s): synthetic pyrethroids
INDICATIONS: CATTLE (beef & dairy)
PARASITES CONTROLLED* (spectrum of activity)
* Country-specific differences may apply: read the product label.
- Biting and nuisance flies: Haematobia irritans (horn flies), Hippobosca equina, (horse flies), Stomoxys calcitrans (stable flies), Musca autumnalis (face flies) and Musca domestica (houseflies).
- Sucking & biting lice (incl. Damalinia bovis, Haematopinus eurysternus and Linognathus vituli).
* Country-specific differences may apply: read the product label.
- Pour on the product along the backline of the animals, from the head to the tail, at the following recommended dose rates:
- <100 kg 10 mL/animal
- 100-300 kg: 20 mL /animal
- >300 kg: 30 mL /animal
- A single application provides protection against flies for 8 to 10 weeks depending on the infestation degree, fly species and weather conditions. Treatment should be repeated within 8 – 10 weeks.
- Sucking & biting lice: 10 ml/animal irrespective of weight. a single application provides protection against lice for 8 to 10 weeks. All in-contact animals must be treated at the same time. A single application is sufficient against lice.
- LD50 (acute oral) in rats: 31-5000 mg/kg depending on the carrier (for the a.i. according to MSDS)
- LD50 (acute dermal) in rats: >2000 mg/kg (for the a.i., according to MSDS)
- Estimated hazard class according to the WHO: III, slightly hazardous
Suspected poisoning? Read the article on deltamethrin safety in this site.
Withholding periods (=withdrawal times) in days for meat & milk (country-specific differences may apply: read the product label)
- Meat: 20 days
- Milk for human consumption: NIL
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:
- Safety for humans
- Safety for domestic animals
- Safety for the environment
- Hazard classifications of pesticides
Risk of resistance? YES, resistance of horn flies (and buffalo flies) and houseflies to synthetic pyrethroids (incl. deltamethrin) is widespread worldwide, and can be very high. Cases of resistance of black flies, stable flies and little house flies to synthetic pyrethroids have also been reported, but prevalence is usually low.
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:
- Macrocyclic lactones (e.g. doramectin, eprinomectin, ivermectin, moxidectin, etc.) only as pour-ons. Injectables and drenches are ineffective against most external parasites.
- Organophosphates (e.g. diazinon)
These alternative products may not be available in all countries, or may not be available as pour-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: UK, Ireland & other EU countries
GENERIC BRANDS available? YES, a few, but not in all countries. BUTOX is the original deltamethrin brand from ROUSSEL UCLAF (later → INTERVET → MERCK AH).
Click here to learn more about GENERIC vs. ORIGINAL drugs.
BUTOX SWISH Pour-on Suspension 0.75% w/v for cattle is one of the numerous insecticidal pour-ons for cattle, sheep and other livestock containing synthetic pyrethroids for the control of flies, lice, mites, ticks and other external parasites. Worldwide there are hundreds if not thousands of such pour-ons. Besides deltamethrin , numerous other synthetic pyrethroids are used in such pour-ons, e.g. cyhalothrin, cypermethrin, permethrin, etc. They all have a similar spectrum of activity and a comparable safety profile.
Deltamethrin is a last-generation synthetic pyrethroid introduced in the late 1970s (BUTOX by ROUSSEL-UCLAF → INTERVET → MERCK ANIMAL HEALTH). It has a broad-spectrum of activity against insects, ticks and mites. During the last decades of the last century it has been very much used against agricultural, domestic and veterinary pests. Nowadays usage has declined because numerous pests (e.g. cattle ticks, horn & buffalo flies, houseflies, sheep body lice, fleas, mosquitoes, cockroaches, etc.) have developed resistance to most synthetic pyrethroids (incl. deltamethrin).
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 animals, 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 in meat and milk.
All pour-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 parasites can survive because the concentration is not high enough to kill them. For this reason such pour-ons are mostly not effective enough against parasites such as ticks & fleas. Irregular spreading may also cause chronic exposure of some parasites to sub-lethal doses, which is known to favor development of resistance.
Control of susceptible (i.e. non-resistant) horn flies 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, horse flies, black flies 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.
All synthetic pyrethroids have a certain repellent effect, mainly on mosquitoes but it lasts usually only a few days, if at all.
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", which have different efficacy and toxicity. Deltamethrin is an exception to this because it consists of a single isomer.
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.