Scrutinise drench regime closely

Three key questions need to be answered by farmers before drenching any sheep this season, according to national worm management strategy group, Wormwise reports Country-wide. 1. Do you know the level of worm burden in the animals you are intending to drench? 2. Do you know if your drench is effective? 3. Have you carried out a Faecal Egg Count Reduction Test (FECRT)? Only a small proportion of sheep farmers in New Zealand know what is happening with regards to drench resistance on their farms. This is leaving them in a precarious position in the fight against worms, according to Wormwise spokesman Trevor Cook. "Only 5% of sheep farmers know what their drench status is," he says, "and with worm burdens being at an all time high on some properties, there has never been a more important time to know your own drench status." He highlights spring and summer as being the most important seasons to know exactly what is going on with each class of stock, and that they all should be treated differently. Ewes that have a reasonable body condition score are unlikely to have a production response from drenching, and therefore drenching should only be carried out if a test shows unacceptable levels of worm activity. Farmers should also leave a proportion of the mob undrenched, as this allows drench susceptible worms to breed with resistant ones and slow the development of resistance by diluting the gene frequency. It is preferable not to use the farm paddocks for the same purposes year after year; for example to always fatten lambs. All paddocks should be exposed to all stock classes during the course of a year, so that the worm population on the farm is continually mixed up rather than having some paddocks populated with worms that have all originated from frequently drenched stock.