The challenge of controlling gastrointestinal nematode (GIN) infection in small ruminants throughout the world is complicated because of GIN resistance to chemical anthelmintics or dewormers.  The problem is particularly severe during warmer months with plenty of moisture, conditions which are conducive to growth and survival of barber pole worm or Haemonchus contortus, a blood-feeding parasite that causes severe anemia in infected animals.  The USDA, Agricultural Research Service in Booneville, AR through collaboration with members of the American Consortium for Small Ruminant Parasite Control (www.acsrpc.org) has conducted research on technologies to reduce the reliance on anthelmintics.  

The FAMACHA^© system was developed in response to drug resistance in resource poor areas as a means of reducing the amount of dewormer used and increasing parasites that have not been exposed to drugs.  The FAMACHA system can be used to determine resistance (an animal’s ability to resist infection) or resilience (an animal’s ability to tolerate an infection) of an animal, which through selection, can lead to a more resistant/resilient flock.  This concept is probably the most important technology for parasite control because parasite resistance is a heritable trait. 

By collecting fecal samples to determine the number of parasite eggs in the sample from young lambs or kids, one can identify more resistant animals (the lower the fecal egg count, the better when comparing a similar group of animals at the same time). The National Sheep Improvement Program (www.nsip.org) has breeding values for parasite resistance, which can help producers determine which animals have the greatest potential for parasite resistance, which is especially useful in selecting replacements.   

Another alternative to chemical anthelmintics, treatment with copper oxide wire particles (COWP) has been used to control H. contortus infection in small ruminants.  COWP (1 – 2 g/animal) can be administered as a capsule or in the feed (COWP is NOT the same as copper sulfate because it is less readily absorbed by the animal and poses a lower risk of copper toxicity when using small doses) and has a short term response of reducing fecal egg counts.  Caution must be exercised when using COWP for parasite control because of the risk of copper toxicity.   

Fresh or dried sericea lespedeza (Lespedeza cuneata) has been examined as a technology to control parasites and is associated with reduced fecal egg counts of H. contortus and reduced clinical signs of coccidiosis.  Lambing in fall compared with spring is a good way to avoid most of the parasites on pasture because lambs become more tolerant as they mature, leading to a reduced need for parasite intervention.  Good grazing management contributes to parasite control. A comparison of continuous and rotational grazing indicated that fewer rotationally grazed lambs required deworming and both groups relied only on COWP rather than chemical dewormer for GIN control.   

Other novel methods examined, garlic and papaya, failed to control internal parasites.  Use of a combination of these technologies, good management, good nutrition and genetics all will enable sheep and goat producers to be productive, even in the face of existing parasites.