November 2013
Copper oxide wire particles to control Haemonchus contortus in small ruminants
By Joan Burke
Research Animal Scientist
Dale Bumpers Small Farms Research Center
Booneville, Arkansas
Haemonchus contortus or barber pole worm is a threat to small ruminants in the southeastern states and as far north as Canada, during warm, moist summers. H. contortus is a blood feeder associated with anemia and death losses of sheep and goats. Due to the presence of anthelmintic (or dewormer) resistance, alternative methods of control are necessary. Copper oxide wire particles (COWP) have been shown to reduce infection of H. contortus, but not other parasitic worms. There are risks involved in using COWP as a dewormer.
COWP administered in a gel capsule or carefully mixed in the feed passes through the rumen and lodges in the abomasum or true stomach, where the adult H. contortus resides. COWP appears to cause damage to the adult worm and likely death, but does not affect immature larvae, which can also feed on blood from the animal.
Copper oxide from COWP is poorly absorbed, but will increase the concentration of copper in the liver. Sheep, and to a lesser degree goats, are susceptible to copper toxicity and too much copper from feed, minerals (loose, block, or as COWP), or forages can lead to death. Therefore, some farmers should not use COWP as a dewormer and others should use the smallest dose possible (0.5 to 1 g for lambs or kids less than 1 year of age; 1 to 2 g for mature animals).
Other forms of copper, including copper sulfate, have not been found to reliably control H. contortus according to ACSRPC research. Copper sulfate is more readily absorbed in the digestive tract of the animal and poses a risk of copper toxicity to sheep and maybe goats (if offered too much) if included in the feed or mineral for parasitic worm control. The ACSRPC research has used Copasure® (Animax) for COWP experiments; other brands of COWP have not been tested, but may not be effective for the control of H. contortus due to the different particle size.
In summary, COWP can be effective for the control of H. contortus, but not other parasitic worms, in sheep and goats, but caution should be used to minimize risks of copper toxicity. For more information on COWP, sources, and gel capsules, see the ATTRA publication, or for references and additional details, see review article presented at the National Goat Conference in Greensboro, North Carolina.
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