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South Australia worms, flies and lice update - May 2018

SA WormBoss Worm Control Programs

SA WormBoss Drench Decision Guides





Adelaide: Colin Trengove, Sheep Health Lecturer (UA Roseworthy campus) (

Sheep in most agricultural areas remain entirely reliant on supplementary feeding apart from parts of the Fleurieu and south east. A green pick has emerged in the mid and lower north but more rain and a few weeks growth is required to amount to significant sheep feed. Consequently, cereal grain and hay is in very short supply with many semi loads of hay sold into the pastoral areas, and around Broken Hill as well.

Worm egg count (WEC) monitoring has indicated significant worm burdens in pregnant ewes, but not in other classes of sheep. This most likely reflects the extra demands of advancing pregnancy and the corresponding reduction in immunity as limited protein is directed to developing foetuses and milk production. Given many/most sheep have been confinement fed in recent weeks/months for efficient supplementary feeding and to prevent overgrazing paddocks, it would have been prudent to monitor and potentially drench sheep prior to this practice.

It is preferable to return ewes to pasture from confinement feeding a month before lambing to minimise stress in late pregnancy as well as the risk of mismothering and disease associated with lambing under high stocking density. Monitoring WECs and drenching on an as-needs basis with an effective drench prior to release would be strategic. Feed may still be sparse in paddocks and so it is debatable about supplementary feeding options on the point of lambing. If ewes are used to lick feeders it is easy to allow them to continue to use these. The debate is more about whether trail feeding is likely to cause mismothering. If it is to be continued it is best done in the early afternoon when there is least lambing activity. Similarly, some prefer to provide hay only from the point of lambing to minimise disruption. Ewes maintained in score 3 condition to lambing should be able to lamb successfully and maintain good mothering despite supplementary feeding alternatives.

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