Animal Health: Should I try copper oxide wire particles to control parasites in my lambs and sheep?

Quite frankly, no! Recently there has been some press announcements regarding the use of copper oxide wire particles (COWP) (sometimes called 'needles') to control Haemonchus contortus (Barber pole worm) infestations in lambs and sheep rather than more familiar dewormers, such as Ivomec® (ivermectin injectable). COWP is touted as an alternative to use if resistance of worms to standard dewormers is occurring. However, sheep producers in Ontario should beware!

Here's what you need to know:

  1. The product is not registered for use in Canada. You will not have assurances that any unapproved product you purchase is efficacious and safe to use in sheep in Canada.
  2. Copper toxicity can be a problem in lambs and sheep in Ontario . The label claim for Copinox is for prevention of copper deficiency. Copper deficiency is not a problem in Ontario.
  3. Research on parasite control with COWP has not been conducted in Ontario. Research has been reported on hairy sheep (southeastern USA), Merino sheep (Australia) and sheep in New Zealand. The results are not directly applicable to Ontario breeds of sheep. Living and management conditions are also very different for sheep in Ontario compared to sheep in southern USA, Australia and New Zealand.
  4. COWP is not 100% effective. COWP reduces (but does not eliminate) fecal egg counts and worm counts for the Barber pole worm in the abomasum (stomach). There is no reduction in the small intestine. In addition, the reduction in counts does not occur in all lambs (at least in those given 2 grams of COWP or less).
  5. COWP is not effective against other worms.
  6. Safety of COWP has not been adequately evaluated. Higher doses (4 or 6 grams) given to 4 to 6 week old lambs did increase liver copper levels above the normal range during the study although clinical signs of copper toxicity were not seen. Label information for Copinox recommends that COWP should not be given to pre-weaned lambs, lambs less than 10 kg in weight, housed sheep or breeds susceptible to copper toxicity.
  7. Health, growth, feed efficiency and economic outcomes have not been adequately evaluated. One study on hairy sheep suggests that COWP given to pregnant hairy ewes one month prior to lambing twins results in smaller lambs at birth and at slaughter. The label claim for Copinox recommends dosing at tupping or during first pregnancy. Dosing in the second or third month of gestation is only recommended if copper deficiency is severe.

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