Wormer Classes in Cattle and Sheep - Clear Wormers

Understanding 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. 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.

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White wormers

Yellow Wormers

Ivermectin product

Understanding 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.