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Weekly Blog

Wormer Classes in Cattle and Sheep - Clear Wormers

June 19, 2020
Wormer Classes in Cattle and Sheep - Clear Wormers
With white and yellow wormers covered in recent weeks, here we look at the popular clear wormer - or macrocyclic lactone - class.
  • Four main actives - ivermectin, moxidectin, eprinomectin, doramectin (also abamectin).
  • In cattle, sold as injectable and pour-on products.
  • In sheep, oral and injectable.
  • Kill both internal worms and external parasites like lice and mites.
  • The have persistent activity against certain internal parasites (some products have more than others).
  • Ivermectin has a 60 day milk withdrawal.
  • Meat withdrawal of ivermectin depends on the mode of admin - pour on = 28 days, injectable = 49 days.
  • Ivermectin/cloursulon injection treats adult fluke as well as worms = 66 day meat withdrawal. Not licensed for dairy cows.
  • Eprinomectin = zero milk withdrawal. Only active licenced for use during lactation.
  • Clear wormers are ideal at housing/dry-off because of efficacy against both internal and external parasites.
  • Avoid over-use in young stock so as to build natural immunity against worms - persistency can hinder this.
  • Use is warranted in first-season dairy calves as they are grazing hard and thus naive from an immunity point of view. Ensure correct treatment intervals are adhered to.
Keep Learning

White wormers

Yellow Wormers

Ivermectin product

With white and yellow wormers covered in recent weeks, here we look at the popular clear wormer - or macrocyclic lactone - class.
  • Four main actives - ivermectin, moxidectin, eprinomectin, doramectin (also abamectin).
  • In cattle, sold as injectable and pour-on products.
  • In sheep, oral and injectable.
  • Kill both internal worms and external parasites like lice and mites.
  • The have persistent activity against certain internal parasites (some products have more than others).
  • Ivermectin has a 60 day milk withdrawal.
  • Meat withdrawal of ivermectin depends on the mode of admin - pour on = 28 days, injectable = 49 days.
  • Ivermectin/cloursulon injection treats adult fluke as well as worms = 66 day meat withdrawal. Milk withdrawal is 60 days.
  • Eprinomectin = zero milk withdrawal. Only active licenced for use during lactation.
  • Clear wormers are ideal at housing/dry-off because of efficacy against both internal and external parasites.
  • Avoid over-use in young stock so as to build natural immunity against worms - persistency can hinder this.
  • Use is warranted in first-season dairy calves as they are grazing hard and thus naive from an immunity point of view. Ensure correct treatment intervals are adhered to.
Keep Learning

White wormers

Yellow Wormers

Ivermectin product