< Back to Outlooks Listing

Victoria worms, flies and lice update - July 2020

Dr Lexie Leonard
Dr Lexie Leonard

Hamilton: Lexie Leonard, Veterinary Consultant, Livestock Logic (l.leonard@livestocklogic.com.au)

Key Points:

  • Continue to monitor weaners every 3–4 weeks until the spring flush
  • WEC sheep prior to marking to determine whether or not drenching is required
  • WECs have generally increased from last year
  • Ensure WEC results are recorded against paddocks as well as mobs to monitor for paddock contamination coming into the spring

Lambing is well underway in the Hamilton region, and marking rates so far are showing an average of 5% increase from last year. Following on from a great autumn break and abundant feed, sheep are in better condition and we are seeing this with increased lamb survival. We are, however, also seeing a lot of feet issues and both hypocalcaemia and pregnancy toxaemia secondary to footsore sheep and also due to inappropriate feeding. While the autumn flush was fantastic, winter has come in fast and cold in many areas, which has pulled up pasture growth, leaving many fat sheep with little to eat. Ensuring lambing ewes have an adequate source of fibre, if on short pasture, will help them maintain blood calcium levels, and in high risk mobs offering lime and salt licks can also help reduce calcium deficiency issues. 

Hand in hand with the wet autumn has come many worm control issues, which we are now seeing raise their ugly heads over lambing.  WECs overall have generally been increased, as have the number of sheep requiring drenching. We have also been finding a lot more resistance to moxidectin LA injections and drench capsules showing up as WEC counts have been positive within the long-acting period. We recommend any property using blanket LA drenches (either injections or capsules) over lambing to have WECs and/or drench resistance tests done progressively to see if these are still working on your property.

This would be a good spring to aim for a drench resistance test as we suspect there won’t be much issue getting WEC results high enough.  Although we have seen an increase overall in WECs and drenching requirements, this is often property-dependent. Properties that have well-managed pastures, well-fed stock and a sound drenching program have mainly had no increase in drenching requirements compared to last year.  One interesting trend we have seen is that pre-lambing drenching has not made a significant impact on the need to drench at lamb-marking, which puts another emphasis on the need to WEC prior to lambing to see if a drench is needed or not. 

Lambs at marking very rarely require drenching, we know it is often done as a ‘feel good’ excercise on many farms, but in most cases, it is probably more prudent to pour the drench on the ground. WEC combined with a pasture assessment and lambs' age will indicate whether or not a drench is indicated or not. Lambs will get most benefit from a drench once they are 14–16 weeks old, if they are grazing contaminated pastures. 

Paid advertisement
Paid advertisement