Tasmania Online FarmPoint Tasmania

Worm drench resistance in sheep (May 2012)

Worm disease is a significant livestock health and welfare problem on some hobby farms and smallholdings. The three greatest causes of drench resistance are - 

  • failing to rotate the class of drench used,
  • underdosing and failing to take the basic husbandry steps to avoid dependence on drench in the first place.  

The smallest quantities of drench that you can buy from conventional sources is, for most brands, a one litre pack. As a result, a range of problems can arise, all of which have the effect of increasing the risk of drench resistance. 

  • The person buys a 1 litre pack and uses it until it runs out, which can mean using the same type of drench for several years.
  • The person buys drench in single doses from a pet shop. As most pet shops that carry drench have only one brand on the shelf, the likelihood is that the person uses the same type of drench over and over.
  • The person scrounges drench from a nearby farmer, which means the drench comes onto the hobby farm without a label showing dose rates.

The DPIPW E website has information on managing worms in small flocks of sheep, prepared for hobby farmers and small holders.