Novel Methods for Sustainable Control of Gastrointestional Nematodes in Small Ruminants

Infection with gastrointestinal nematodes (GIN) is a primary constraint to profitable goat and sheep production in the southern US, Puerto Rico (PR), and the US Virgin Islands (USVI). The primary objectives of this project were to determine prevalence of anthelmintic resistance in small ruminant GIN throughout these regions, to educate producers as to the need to reduce dependence upon chemical dewormers, and to develop and test novel, non-chemical parasite control technologies. On-farm anthelmintic resistance tests were completed on sheep and goat farms in GA, FL, LA, AR, PR, and the USVI, with a high prevalence of resistance detected to most of the drugs currently available to control parasitic nematodes. Producer workshops were held in each participating region to disseminate information on parasite biology, proper use of anthelmintics (smart drenching), and targeted deworming using the FAMACHA system to identify only those animals in the herd or flock that actually require treatment. This technology, based upon color of the eyelid to detect level of anemia, was developed for use with sheep in South Africa, and was validated for use with sheep and goats in the southern USA, PR, and USVI as part of this project. The number of FAMACHA workshops held yearly is continuing to expand, and approximately 8000 FAMACHA cards have been sold for on-farm use to date, resulting in much less usage of chemical anthelmintics and lowering of deworming costs. Fact sheets on smart drenching and FAMACHA technology are posted on a project web site maintained by the Southern Consortium for Small Ruminant Parasite Control (SCSRPC.org). Novel GIN control techniques that were tested in sheep and goats in this project included use of nematode-trapping fungi, copper oxide wire particles (COWP) and forages containing condensed tannins (CT), specifically dried forms of sericea lespedeza. Each of these technologies were effective against small ruminant GIN, either reducing fecal egg counts and adult worm numbers, or improving blood packed cell volume (anemia score) compared to control treatments. Combinations of limited anthelmintic use (targeted deworming) and novel techniques in integrated small ruminant GIN control programs are needed and are still being tested.

Project objectives:

1. Bring about immediate improvements in GIN control and subsequent productivity in small ruminant operations in the southern US and the USVI by disseminating current state-of-the-art knowledge and technology to producers
2. Investigate and implement the use of novel non-chemical approaches in integrated, sustainable control strategies of GIN in small ruminants
3. Determine the economic impact on the small ruminant industry of uncontrolled multi-drug resistant GIN.

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.