This group of drenches is active against parasites in the upper gut, that is, the 4th stomach (abomasum) and in the upper small intestine.

They have very little or no effect on worms in the large intestine such as nodule worm. The active in this group is naphthalophos, an organic phosphate compound.

They can be toxic if used inappropriately. Naphthalophos is also used in some combinations.

In this section:

• Naphthalophos (NAP or OP)

 Naphthalophos (NAP or OP)

Naphthalophos (NAP) is an organophosphate (OP) compound that is often referred to as a 'mid-spectrum' treatment. It has good activity against adult and immature barbers pole worm and variable efficacy against other sheep worms (generally efficacy between 70 and 90 percent depending on the worm species and stage of the lifecycle).

All drenches should be tested for efficacy on your property, preferably before you use them. Resistance to NAP drenches has not been reliably reported, so it is a useful product against barbers pole worm and scour worms. Even though resistance (if any) is rare, you should include NAP in any drench resistance tests on your property. Being an organophosphate chemical, care is needed to prevent toxicity in both sheep and other mammals. Treated sheep should not be left in the yards without water, particularly in hot weather.

Various mixtures and products are now available where NAP and other drench groups (white, clear, combination or ML's) are used together to increase efficacy. Before using combinations containing NAP ensure that you have tested the efficacy of the other components against the worms on your property using a drench resistance test and larval cultures.

If the results are not clear cut, seek professional advice before using them. A number of the brands below can be mixed with other drenches. You should check the labels or contact the manufacturer for correct mixing instructions.

Brands:

• RAMETIN
• COMBAT Se

 RAMETIN SHEEP DRENCH

 COMBAT SE