Cattle Parasite Management

Worms in Cattle 

Worms in cattle are associated with ill-thrift and diarrhea, as sheep that are affected by worms are.  Single Macrocyclic Lactone (ML) drenches such as ivermectin (Imax CD®) and moxidectin (Cydectin®) in injectable and pour-on form are the best type of chemical treatment when drench resistance is not suspected.  These drenches also control some types of lice and ticks.  However, combination drenches which incorporate an ML drench, and one or more other chemicals are a better option to treat worms in cattle where drench resistance has developed.  Most adult cows carry minor worm burdens, so only adult cows showing signs of worm disease require treatment.  Weaners or yearlings should however be treated at weaning and if you have worm issues on your farm, a preventative autumn drench is recommended for both weaners/yearlings and two year olds/first calf heifers.  Finally, a preventative autumn drench for your bulls before joining can be a good practice as bulls are more susceptible to the effects of worms than adult cows are.  

Lice in Cattle

While lice in many cases do not cause an economic impact to cattle, it is important to treat lice infestations when they become evident through cattle rubbing on fences and other structures.  As with sheep, lice are spread by direct contact with other cattle and cattle in poor condition are more susceptible.  As a result, fence maintenance is important to reduce the possibility of contact with other infected cattle and in the event of a lice infestation it is important to treat all cattle on the property at the same time.  If possible, treat cattle for lice in autumn, prior to calving and before louse numbers build up over the winter period (lice like dark, cool, and damp environments).  If this is not possible, simply ensure all cattle on the property are treated at the same time to eradicate lice.   

Most insecticides are not effective against louse eggs.  Accordingly, a second follow-up treatment later is necessary with most products.  The timing of the follow up treatment is critical, as it allows time for the eggs to hatch but not to mature into adults that are laying eggs.  When you select a chemical product be aware of associated withholding periods and export slaughter intervals and the fact that not all products control both the biting and sucking types of lice.

Pour-on treatments or backliners are the most widely used treatment.  We have four power dosers that are available for client use.  We also stock insecticidal ear tags, and spray treatments.  Spray treatments however require thorough dousing of cattle with insecticide, so are often only used to treat small numbers of cattle. 

Happily, there are some ML worm drenches on the market (either backline or injected subcutaneously) that also control lice.  Some lice products are however not compatible with particular worm treatments.  Just ask us what the best chemical options are to suit your herd’s requirements. 

For additional useful websites visit: Liceboss and Wormboss websites are also useful. 

If you have any questions about Cattle Parasite Management, please give us a call on 9651 1312 or drop in to our Moora or Yerecoin store. We are an independent local family-owned Western Australia rural store, and we love sharing our knowledge and experience with our customers.