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South Australia worms, flies and lice update - April 2017

SA WormBoss Worm Control Programs

SA WormBoss Drench Decision Guides





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

The year continues in reverse going from a relatively wet summer to a dry late autumn and predictions of a late break. This has moderated the influence of worms on sheep health both through sheep being in very good condition following the feed abundance during summer and the corresponding reduced worm challenge more recently.

Recent monitoring, mostly in pregnant ewes, has indicated moderate to low worm burdens in most mobs assessed around upper South East through to Eyre Peninsula. This highlights the benefit of pre-lambing monitoring as drenching may not be indicated if counts are low and ewes are in good condition. This not only saves on the time and cost of an unnecessary drench, but also reduces the stress on the pre-lambing ewe...but not forgetting the importance of a booster vaccine at this time.

Another form of monitoring is following lines of lambs or adults through the abattoirs. This is usually very informative for stock owners as often factors impacting health and growth are revealed that may not be reported. One example is “pimply gut” resulting from large bowel worm infestations. Another is the presence of lungworm often leading to pneumonia and pleurisy which can have a severe impact on growth rate and health, but commonly not reported. Furthermore, this is not detected by faecal egg count monitoring unless lungworm testing is specifically requested. All stock owners should follow at least the occasional consignment through the abattoirs to see what they can do to improve the health and productivity of their livestock enterprises.

The good feed conditions during joining should have helped to optimise conception rates, but hopefully a forecast late break doesn't impact lamb survival. Drier conditions usually suit lambing and moderate body condition will support lactation even if feed is short. From a worm control perspective seasonal conditions need to be exceptionally bad before a pre-weaning drench would be considered. We will have to wait until May to see if the long term forecast pundits are on target and how that affects reproductive outcomes. 

For April 2017 state outlooks, please follow the links below:
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