Is your drenching effective?
The autumn is a good time to do a “drench check” faecal egg count. By now the lambs have been drenched multiple times so if there are any drench resistant worms on the farm they will be concentrated in these lambs making a “drench check” more reliable. It is also a good way to make sure that the drenching procedures are working.
One to two weeks after drenching collect 10 individual faecal samples direct from lambs or fresh from the ground. Keep them cool or in the fridge until you can get them to your vet or drench retailer as this will slow the hatching of the eggs. If the faeces are warm the eggs will hatch and the test will be less effective. If you have a faecal egg counting kit on farm make sure you do individual samples rather than a mob sample as one lamb that may have missed a drench will confuse the result.
The presence of eggs in these samples indicates that there are adult worms still in the lambs so these were not killed by the drench which may be a result of drench resistance, ineffective drenching technique or lambs not being drenched. You will only know this by doing a “drench check” faecal egg count