Although the principle of Target Selective Treatment (TST) has become
accepted as a valuable tool in reducing the speed of onset of anthelmintic resistance
(AR), and a key part of sustainable and holistic integrated management of
parasites(SHIMP), the only practical and proven on–farm method developed to date has
been the FAMACHA© system of clinical anaemia evaluation. This by its nature is
limited to use in the few haematophagous parasites that cause anaemia, especially
Haemonchus contortus.
The principle of TST can be extended for use against other important internal
parasites, provided that the system developed is practical, economical and reasonably
indicative of some form of important parasitism. The candidates for an extended TST
system have included nasal discharge (for botfly larvae), ocular mucous membranes for
anaemia (for haematophagous worms), submandibular oedema or bottle jaw (for
haematophagous worms and conical fluke), body condition score (for worms causing
loss of condition) and faecal fouling or dag score (for worms causing diarrhoea). Each
of these checks have their limitations and problems but for the present they are the only
practical ways of deciding which animals will benefit from treatment during routine
inspection on the farm. A practical, farmer- friendly guide has been developed to enable users to
examine sheep (or goats) rapidly, make effective assessments, identify the likely
parasites, identify anthelmintic groups that could be used, use practical systems for
temporarily identifying treated animals and to know the limitations of the system. The
system has been called the Five Point Check (5•√©) for international, multilingual use
and constitutes a further, practical extension of TST. This can make a useful
contribution to SHIMP. The new system can be summarised in the slogan ―LEAVE
THE BEST and TREAT THE REST‖ and has an important shift in emphasis from
identifying animals that need treatment to identifying those that are unlikely to benefit
from treatment. Rather than dosing all animals, we advocate ―LOOK BEFORE YOU TREAT".