June seasonal focus

As the winter months are now upon us, a timely reminder to be on the look-out for some of our usual suspects, and also proactively manage to maintain smooth sailing for your livestock over the winter period.

Cattle lice are likely to be visible in the cooler months. There are two types of lice – biting and sucking. Choosing which application method can help with effectiveness in controlling these pests. Sucking lice are controlled most effectively by injectables (as the product is taken up by the lice via the bloodstream when they are feeding on the blood) and biting lice are well controlled by pour-ons where they come in direct contact with the lice. See details in the LiceBoss product search tool.

Once the rubbing is obvious, the lice have been present for a little while. Rubbing from lice creates bare areas in the hair coat of cattle. This allows rain into skin level and leads to poor welfare outcomes for cattle. Bare patches persist until cattle grow a new coat back, so it may take weeks to months before cattle appear visually recovered from a lice burden.

If you are unsure what type of lice are present, you are not alone! Lice are small and it is difficult to distinguish between the two different types. Look on the LiceBoss website for details of types of lice. Collect some lice from the cattle and look at them under a magnifying glass or send them (properly packaged) to a parasitology laboratory for identification.

Ongoing monitoring of internal parasite populations via worm egg counts now will help plan for preparing necessary treatments based on worm egg counts and thresholds according to class of livestock. It is also a good time to be working on preparing weaning paddocks or lambing/kidding paddocks. Use your knowledge of the sensitivity of different worm larvae and eggs under different climatic conditions to help you gain an upper hand on these mostly invisible parasites.

Also important to consider when choosing a treatment, is to select a product that is registered and appropriate for the worms present, contains a combination of actives, and the withholding period and export slaughter intervals fall within your marketing specifications. Goat producers are strongly advised to work in close collaboration with your veterinarian, who will help you with individual herd worm management.

Long-acting treatments such as moxidectin injection may not control worms for as long as the label states. This is because resistance onset since the time of registration (up to 20 years ago) has meant internal parasites can live happily with higher levels of moxidectin inside the sheep. Check if your mob is still protected by doing a worm egg count at convenient times after injection- for example a week prior to lamb-marking or weaning. This allows you to prepare for a ‘tail-cutter’ or ‘exit drench’ to clean out the resistant parasites that have accumulated in the sheep.

Strategic drenching of weaner cattle is advised to avoid unnecessary setbacks that arise as a consequence of the stress of the weaning process. It is important to use combinations here as well, to minimise the onset of drench resistance in your herd. If you are unsure about what drench to use, it is easy to conduct a DrenchCheck. This simply involves taking samples from a selection of the mob on the day of treatment for a worm egg count and worm identification (larval differentiation), then following up 14 days later with samples from the same cattle. The resulting worm egg counts will tell you exactly how well the treatment has worked against each species of parasite present.

It is also important to remember that using one chemical group for both internal parasites and external parasites will select for resistant parasites. It is advised to use different chemical actives for internal and external parasites.

Worms in northern cattle. Reports from the Dawbuts Laboratory indicate that cattle in North Queensland and the Northern Territory are carrying high worm burdens that affect their general health as well as their growth rates.

Tests conducted between March and May 2024 show many mobs of weaners and yearlings with worm egg counts ranging from 350 eggs per gram up to 900 eggs per gram. Depending on the type of worm involved (find out by asking your lab to conduct a worm identification) this level of worm burden can check growth rates (average daily gain) by a third and cause medium to long-term damage to the gastrointestinal tract. The most common type of worms found in these northern cattle were barber’s pole worms and small intestinal worm (Cooperia), with the bulk of the Cooperia being the tropical variety.