Pre-lamb drench options
With rising diagnosed drench resistance on farms around New Zealand, it is vital to rethink how we use drench, what we drench and how to manage parasites differently. So, what are the various options for managing parasites in ewes this season?
Firstly, aim to have most ewes at body condition score (BCS) 3 to 3.5. Ewes in good condition and on adequate feed should not require a parasite treatment. Timelines are getting tight to achieve this now, but preferential feeding of some light ewes, coupled with scanning data and potentially selling very light (less than BCS 2.5) or single-bearing ewes, may free up feed to achieve this.
When ewes are set stocked for lambing, avoid the wormiest paddocks, especially for those most susceptible to parasites. These are paddocks that lambs and hoggets mainly grazed during late summer or autumn and may not have had the benefit of the vacuum cleaner effect from older ewes or even better, cattle. Mature fit ewes who are not under pressure can be used to clean pasture along with cattle, so there are fewer larvae for susceptible stock to ingest. However, once lambing comes around, ewes should be considered more susceptible to parasites and should not be exposed to heavily contaminated pasture at this time.
When the inevitable happens and ewes are not up to BCS 3, or feed is lower than ideal and a worm burden is identified, consider which effective drench to use. If you are unsure what product works on your farm, organise a drench test with your local PGG Wrightson Technical Field Representative.
A short-acting oral drench cleans out the parasite burden in ewes, but they get reinfected soon after. If a ewe is in poor condition or under pressure, the loss associated with parasites is greater. This is where long-acting products such as Cydectin® Injection, Eweguard® and longer-lasting Cydectin Long Acting Injection for Sheep gives potential protection to ewes from larvae for longer due to persistent activity claims. In the case of Cydectin Long Acting Injection for Sheep, protection of up to 112 days against Teladorsagia circumcincta is provided.
Trials¹ ² have shown poorly conditioned ewes treated with Cydectin Long Acting Injection for Sheep weaned in heavier condition and so have their lambs. Selectively treating ewes to maintain refugia is a tool for slowing resistance. This may include giving a 5-in-1 vaccine to better conditioned ewes or Eweguard, Cydectin Injection or Cydectin Long Acting Injection for Sheep to those needing more parasite protection.
Talk to your local PGG Wrightson Technical Field Representative to understand the suitability of using Cydectin® products within your farm system.
1 Miller, C.M., Ganesh, S., Garland, C.B., & Leathwick, D.M. (2015). Production benefits from pre- and post-lambing anthelmintic treatment of ewes on commercial farms in the southern North Island of New Zealand. New Zealand Veterinary Journal.
2 Bingham, C., Hodge, A., & Mariadass, B. (2017). Comparison of two long-acting pre-lambing anthelmintic treatments on the productivity of ewes in low body condition. New Zealand Veterinary Journal.
Registered according to the ACVM Act 1997, Cydectin® Long Acting Injection for Sheep #A009926, Cydectin® Injection #A005979 and Eweguard® #A007302. Always read the registered label before use.
