A Systems Approach to Control Gastrointestinal Nematodes (Gin) in Organic Small Ruminant Production
Dale Bumpers Small Farms Research Center
2012 Annual Report
1a.Objectives (from AD-416):
The objectives are to examine farm management systems for year-round gastrointestinal nematode control, identify resistant animals to minimize problems with nematode infection, conduct on-farm studies on the feasibility of techniques developed from research studies, and educate outreach professionals and producers on adopting available organic gastrointestinal nematode control strategies in small ruminants by disseminating state-of-the-art knowledge and procedures.
1b.Approach (from AD-416):
The impact of continuous use of integrated methods that have been developed by these investigators previously will be examined using a systems approach in a long-term experiment. Groups of sheep or goats using different control strategies will be managed separately for at least four years, and infection level and production efficiency will be measured. Forage systems (including sericea lespedeza and birdsfoot trefoil) will be examined to minimize parasite infection. Genetic selection for resistant sheep and goats will be examined by correlating fecal egg counts of parents and offspring, and selected sires will be used to generate stock with a greater resistance to parasites. Integrated approaches described above will be examined on-farm by producers who will submit information on the success of approaches employed.
Scientists from the USDA/ARS Dale Bumpers Small Farms Research Center, Booneville, Arkansas, Louisiana State University, and Fort Valley State University funded by USDA NIFA OREI and USDA SBIR grants are examining the effects of sericea lespedeza leaf meal pellets on the control of coccidiosis in lambs and goat kids, an economically devastating parasitic disease that affects livestock and poultry. Coccidiostats are often ineffective and are not allowed in organic production. Condensed tannins from sericea lespedeza reduced the number of Eimeria spp. oocysts found in the feces of lambs and kids, and reduced the clinical signs of coccidiosis. Reduction of coccidiosis will increase feed efficiency and reduce death loss of livestock.
Concurrently, these scientists are examining the long-term feeding of sericea lespedeza to aid in the control of gastrointestinal nematodes in sheep and goats. Gastrointestinal nematodes are the greatest threat to the health of young lambs, and kids and adult females around the time of parturition. Dewormer resistance means many commercial drugs are ineffective. Incidence of deworming is reduced in sericea lespedeza-fed animals; however, long-term feeding may affect mineral availability to the animal. An understanding of how this impacts the animal is currently under investigation. The mechanism of action of condensed tannins in sericea lespedeza on worms has not been determined. Adult worms recovered from sericea lespedeza fed goats were examined for evidence of surface damage using scanning electron microscopy. Although not consistently, there were constricted folds and a disheveled or damaged outside surface on some of these worms, but there was no damage on worms recovered from control goats. This suggests a direct effect of sericea lespedeza on the cuticle of the Haemonchus contortus.