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