Sheep and goat production is a viable enterprise, offering opportunities for marketing meat, fiber, and milk, plus grazing services for public agencies, solar farms, and others. Their small size and low cost make them appealing for small farms, including ones with limited resources, and they are adaptable to many different production systems. Small ruminants (sheep and goats) can be raised with relatively few inputs, but the control of internal parasites, especially gastrointestinal nematodes including Haemonchus contortus (barber pole worm, stomach worm), is often a huge production challenge. Parasite control is particularly challenging in warm, humid regions, including the summer months in much of the United States. Grazing animals ingest infective larvae from grass and shorter forages. The larvae develop into adults in the “true” stomach (abomasum) 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. The eggs require warmth and moisture to hatch and to move onto forage plants, which is why internal parasites are problematic, especially during the summer and in times of rainfall or irrigation.
Internal parasites have become more difficult to manage in small ruminants because of their increasing resistance to all available chemical dewormers. Pastures with heavy stocking rates in high-rainfall regions are especially vulnerable to parasite buildup. The costs of internal parasite infection include treatment expenses, reduced animal weight gains and performance, and even death.
In response, the American Consortium for Small Ruminant Parasite Control (ACSRPC, referred to in this fact sheet as “the consortium”) was formed. This group of researchers, veterinarians, and Extension educators has worked since 2001 to find practical, research-backed ways to manage internal parasites, improving the viability of sheep and goat production as a result. The consortium got its start thanks to two SARE Research and Education grants (LS01-124 and LS02-143), and has greatly expanded over the years. Currently, the consortium offers the most current, science-based information and training on their website, www.wormx.info. The consortium 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)
- genetic selection of parasite-resistant animals
- use of parasite-resistant breeds
- providing nematode-trapping fungi
- and other alternative methods
This fact sheet provides basic information on each approach, and cites resources for training and further information. Much more information can be found on the consortium’s website and the ATTRA website.