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South Australia worms, flies and lice update - June 2014

Adelaide: Colin Trengove, Sheep Health Lecturer (UA Roseworthy campus) (trengovet@icloud.com)

Winter has finally arrived in SA with substantial rainfall in June and most parts of the state are looking good. Monitoring ewe condition and pasture growth as part of ‘Life time ewe management’ in the upper south east in late June revealed soil temperatures around 13–16 degrees and so pastures and crops will still be growing steadily at 20+ kg dry matter/hectare/day. Talk of El Niño seems a distant concern at this stage and hopefully any potential impact will be minimal if it does eventuate later in the year.

Worm egg counts have been modest with mostly younger sheep having elevated numbers. This is to be expected as adult ewes have been able to maintain good condition with the early break in the upper half of the state and so their immunity has minimised the worm population. In contrast, hoggets and lambs have not acquired immunity and so are not able to suppress worm populations.

Monitoring worm counts should be done every 1–2 months through winter to determine if a salvage drench is required as worms happily survive throughout winter presenting a constant risk to grazing livestock—especially those on short pastures.

Similarly, lice flourish in the winter months with generally longer wool for protection and minimal UV light to ‘zap’ them. The good news is that it is too cold for flies to be breeding with ambient temperatures well below 17 degrees and so strikes will not be occurring.