Sheep and goat production is a growing enterprise for small and limited resource farmers in the North Central region. While small ruminants (sheep and goats) are adaptable to many different production systems and can be raised with relatively few inputs, they present production challenges. For instance, control of internal parasites, especially gasrointestinal 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. In Ohio, researchers are examining the use of forage chicory as part of a gastrointestinal nematode parasites control strategy for sheep.
“Sheep farms that utilize managed grazing are both economically profitable and environmentally sustainable,” said Bill Shulaw, professor and Extension Veterinarian and at the College of Veterinary Medicine at Ohio State University. “In our region, perhaps the greatest threat to this production system is gastrointestinal parasites, especially the blood feeding Haemonchus contortus. Loss of productivity associated with parasite infections is usually more costly to the farmer than animal deaths, although mortality attributed to parasite infection can be significant too.”
In 2008, Shulaw, together with Ohio State Extension Educators Rory Lewandowski and Jeff McCutcheon, applied for a NCR-SARE Research and Education grant, and was awarded $137,150 to measure animal performance and the potential of plant secondary metabolites found in forage chicory to reduce the impact of parasite infections in sheep.
“Research reports describing plants with possible activity against internal parasites in sheep and goats have been appearing for several years,” said Shulaw. “Here in the U.S., much of the work has focused on Sericea lespedeza and the role of condensed tannins (CT). However, this plant is not particularly desirable in our region, and other reports, mostly from outside the U.S., have suggested that forage chicory might also be useful.”
As the team began investigating forage chicory as a parasite control strategy, they learned that Dr. Joyce Foster and her colleagues at the USDA’s Agricultural Research Service Appalachian Farming Systems Research Center had conducted research with several varieties of forage chicory studying its nutritional value and palatability for small ruminants. They contacted Foster, and together the team of four had collective expertise in sheep management, management intensive grazing techniques and forage production, internal parasite biology and control, and in forage chicory, including the biochemistry that might be involved. The team worked with farmers John Anderson, of Shreve, OH, Curt Cline of Albany, OH, and Bruce Rickard of Fredericktown, OH.
The two-year, on-farm, research project sought to determine the usefulness of a non-traditional forage, forage chicory (Cichorium intybus L.), in controlling gastrointestinal nematode parasites (GIN) in grazing sheep. A comparison forage, brown mid-rib (BMR) forage sorghum (Sorghum bicolor (L.) Moench.) x sudangrass (Sorghum sudanense Piper) hybrid was used to provide a comparable forage to provide a low, or no, parasite challenge. SARE’s Agricultural Innovations fact sheet, Sustainable Control of Internal Parasites in Small Ruminant Production, provides basic information on each parasite approach and cites resources for training and further information. It’s available online at sare.org/SmallRuminant
“Chicory contains sesquiterpene lactone (SL) and small amounts of condensed tannins, and it has been shown to have negative effects on the survival of adult and larval stages of internal parasites of sheep and farmed deer in research conducted in other countries,” said Shulaw. “Published research suggests that the SL concentration is likely the principal factor affecting parasite numbers although this is still incompletely studied.”
Statistical analysis of the data collected over the two-year period revealed that during the respective grazing periods, lambs grazing the BMR gained slightly more weight than the lambs grazing the chicory, but the fecal egg count (FEC) of the lambs grazing the chicory increased less than those grazing the BMR. Shulaw believes that this suggests that the antiparasitic effect of chicory was attributable to a direct effect on GIN. Given the slightly superior weight gain in the BMR lamb groups, Shulaw thinks there was an antiparasitic effect on the GIN in the lambs grazing chicory, at least with regard to their egg output, and that this was likely due to a direct effect of chicory on the worms (as opposed to merely an effect of improved nutrition for chicory, as has been suggested in other studies).
“Our project examined just one piece of a very large problem in the sheep and goat industries,” said Shulaw. “Going into it, I don’t think any of us, farmers included, believed that forage chicory would be the ‘silver bullet’ that solved the parasite control problem. But we all learned a great deal about various forages, grazing techniques, and the complexities of internal parasite control. I believe that it is this continual questioning and learning process, coupled with applying what we learn, that contributes to sustainability in agriculture.”
Bill Shulaw’s research team created a multi-page fact sheet that describes basic parasite biology for gastrointestinal worms acquired by sheep and goats on pastures, and provides several strategies for managing internal parasitism. It’s available online.