Brand: EXTINOSAD ® Pour-on for Sheep

Company: ELANCO

FORMULATION: «pour-on» for topical administration evely along the backline from the pol to the base of the tail, in two bands.

ACTIVE INGREDIENT(S): Spinosad: 2.0% = 20 g/L

CHEMICAL CLASS of the active ingredient(s): Spinosyn


PARASITES CONTROLLED (spectrum of activity)

  • Sheep body lice Bovicola (Damalinia) ovis, off-shears and with long wool.


* Country-specific differences may apply: read the product label.

Sheep weight (kg) Dose rate (mL)
Off-shears (within 24 hours after shearing)
20 - 35 15
36 - 55 20
56 - 75 25
Add 2 mL for each 5 kg above 75 kg
Unshorn suckling lambs
Up to 9 kg 5
10 - 19 7.5
20 - 29 15
Add 3.5 mL for each 5 kg above 29 kg
Long wool (6 - 12 months after shearing)
Adults (>6 months old) 50


  • LD50 (acute oral) in rats: 5000 - 20000 mg/kg (according to MSDS)
  • LD50 (acute dermal) in rabbits: >2000 mg/kg (according to MSDS)
  • Estimated hazard class according to the WHO: U = Unlikely to present acute hazard in normal use.

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

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

  • Meat:
    • Australia: off-shears and lambs 14 days; long wool NIL.
    • New Zealand: NIL
  • Wool: Australia & New Zealand : NIL.
  • Milk for human consumption: Do not use on female sheep which are producing, or may in the future produce, milk or milk products for human consumption.

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

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


Risk of resistance? LOW, in sheep body lice.

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

Spinosad, a natural insecticide belonging to the class of the spinosyns was introduced for body lice control of sheep in Australia in the early 2000s. So far there are no reports on resistance or tolerance of sheep body lice to spinosad in Australia or New Zealand. However, other pests have already developed resistance to spinosad (e.g. houseflies) in several countries. And in the past, body lice have developed resistance to several classes of insecticides (e.g. synthetic pyrethroids, benzoylphenyl ureas) in Australia and New Zealand. Consequently it must be assumed that they will sooner or later develop resistance to spinosad as well, particularly if it is uninterruptedly used during years. To delay resistance development Integrated Pest Management (IPM) practices are a must, including product rotation with lousicides showing mechanisms of action different from that of spinosad.

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 pour-ons.

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? NO, so far.

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

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


EXTINOSAD Pour-on for Sheep from ELANCO is one of the few products containing spinosad introduced for livestock so far.

Spinosad was introduced in crop protection already in the 1990s, but veterinary products were introduced only about a decade later. For the time being there are no livestock products containing spinosad in the US or the EU. 

Spinosad is a natural insecticide obtained from soil bacteria and was introduced in crop protection already in the 1990s (ny ELI-LILLY). But veterinary products were introduced only about a decade later. For the time being there are no livestock products containing spinosad in the USA or the EU. It is effective against numerous insects pests (e.g. lice, fleas and flies, etc.) and also against ticks and mites. It is moderately used in agriculture as well as in domestic and public hygiene. It is also used against fleas on dogs and cats, and against poultry mites. It has no effect whatsoever on internal parasites (roundworms, tapeworms, flukes, etc).

One of its major benefits is the rapid degradation of spinosad in the environment and the low residues it leaves in animal tissues. Its major weakness for use on livestock is the rather short residual effect after topical administration.


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.