Chemical Groups and Actives for Cattle

Cattle parasite treatments

Cattle parasite control requires the use of treatment products for both internal (endo-) and external (ecto-) parasites as part of an integrated parasite management (IPM) program. There can be a degree of crossover in parasitic effect between products used for controlling internal (gastro-intestinal nematodes, tapeworms and flukes) and external parasites (ticks, flies, lice and mites) when a treatment is applied. Best parasite control is achieved when a treatment is chosen for best effect against the primary targeted pest, but the effects on other parasites, as noted on the label, should also be considered. To reduce the build-up of resistant individuals within populations it is important to consider other parasites when treating.

Chemical activity

Each parasiticide has a particular chemical structure or ‘active’ component. The active operates to disrupt an essential life process in the parasite. Actives within the same chemical group generally have a similar mode of action and target the same life processes. Therefore if resistance develops to one chemical active in a group this usually confers cross resistance to other chemicals in the same group. Chemical mixtures and combinations incorporate two or more active ingredients; mixtures use multiple actives to target different parasites and chemical combinations use multiple actives to target the same parasite.

Chemical groups for treating cattle against lice and mites

1. Synthetic pyrethroids (SPs): treat lice, flies and ticks
2. Organophosphates (OPs): treat lice, flies and ticks
3. Macrocyclic lactones (MLs): treat lice, mites, roundworms, flies and ticks
4. Insect growth regulators (IGRs): treat lice and cattle tick
5. Rotenone and sulfur: treat lice
6. Chemical mixtures and combinations

Chemical groups for treating cattle against worms

1. Macrocyclic lactones (MLs): treat roundworms, lice, ticks, flies and mites
2. Benzimidazoles (BZs, ‘white drenches’): treat roundworms, tapeworms and liver fluke
3. Imidazothiazole (levamisole, ‘clear drenches’): treat roundworms
4. Nitroxynil: treat liver fluke and roundworms
5. Sulfonamide (clorsulon): treat liver fluke
6. Salicylanilide (oxyclozanide): treat liver fluke
7. Amino-acetonitrile derivatives (monepantel): treat roundworms
8. Chemical mixtures and combinations

Chemical groups for treating cattle against ticks

1. Synthetic pyrethroids (SPs): treat ticks, flies and lice
2. Organophosphates (OPs): treat ticks, flies and lice
3. Macrocyclic lactones (MLs): treat ticks, roundworms, lice, flies and mites
4. Insect growth regulators (IGRs) or Tick Development Inhibitors (TDIs): cattle tick and lice
5. Amitraz: treat ticks
6. Chemical mixtures and combinations

Chemical groups for treating cattle against flies

1. Synthetic pyrethroids (SPs): treat flies, ticks and lice
2. Organophosphates (OPs): treat flies, ticks and lice
3. Macrocyclic lactones (MLs): treat flies, roundworms, lice, ticks and mites
4. Chemical mixtures and combinations

Chemical groups for premises treatments to kill nuisance flies

1. Synthetic pyrethroids (SPs): treat premises flies
2. Organophosphates (OPs): treat premises flies
3. Insect growth regulators (IGRs): treat premises flies
4. Carbamates: treat premises flies
5. Oxadiazines: treat premises flies
6. Neonicotinoids: treat premises flies
7. Spinosyns: treat premises flies
8. Chemical mixtures and combinations

Chemical actives will vary in their effect on the different parasite groups depending on their formulation and application method. For help in selecting a product to treat specific parasites use this link: