Sustainable Control of Internal Parasites in Small Ruminant Production

Sheep and goat production is a growing enterprise for small and limited resource farmers. Small ruminants (sheep and goats) are adaptable to many different production systems and can be raised with relatively few inputs, but they face huge production challenges. Control of internal parasites, especially gastrointestinal nematodes including Haemonchus contortus (barberpole worm, stomach worm), is a primary concern for many sheep and goat producers and is particularly challenging in humid regions. Grazing animals ingest infective larvae from grass and shorter forages. The larvae develop into adults in the abomasum (true stomach) of ruminants. The adult parasites feed on blood in the abomasum and lay their eggs, which are excreted in the ruminants’ feces. The life cycle continues when the eggs hatch and larvae develop on pasture, where they can be ingested by the grazing ruminants.

Internal parasites have become more difficult to manage in small ruminants because of the parasites’ increasing resistance to all available chemical dewormers. Parasite problems negatively impact the animals’ health, reduce productivity and increase treatment costs. Pastures with heavy stocking rates in high-rainfall regions are especially vulnerable to the buildup of parasites. The cost of internal parasite infection includes treatment expense, reduced animal weight gains and performance, and even animal death.

In response, the Southern Consortium for Small Ruminant Parasite Control (SCSRPC) has investigated several methods of sustainable gastrointestinal nematode parasite control, including Smart Drenching (including FAMACHA©), copper oxide wire particles (COWP), condensed tannin-containing plants, specifically sericea lespedeza (Lespedeza cuneata), selection of resistant breeds and other alternative methods. This fact sheet, Sustainable Control of Internal Parasites in Small Ruminant Production, provides basic information on each approach and cites resources for training and further information.