Non Technical Summary
Infection with gastrointestinal nematodes (GIN), particularly Haemonchus contortus, a highly pathogenic blood-feeder, is the primary constraint to economic production of sheep and goats in the southern and eastern USA. Small ruminant producers are rapidly running out of chemical control options due to widespread GIN resistance to available anthelmintics. Newer anthelminties for cattle and sheep are available that could potentially be useful in sheep and goat integrated parasite control. Several non-chemical novel parasite control technologies, such as FAMACHA for targeted selective treatments (TST), copper oxide wire particles (COWP), and grazing or feeding of the high-tannin perennial legume Sericea lespedeza have been tested and validated by the American Consortium for Small Ruminant Parasite Control (ACSRPC). In the proposed work, the efficacy of two new anthelmintics- LongRange and Zolvix, will be evaluated for sheep and goats GIN control. A combination of chemical and non-chemical novel integrated parasite control strategies for small ruminants will be tested. The results will be distributed to producers, scientists, and other clientele groups in U.S. and worldwide through the ACSRPC website, scientific and producer oriented publications, and presentations at scientific meetings and producer workshops.
Animal Health Component
Research Effort Categories
Goals / Objectives
Our objective in this proposed project would be 1) to evaluate anthelmintic efficacy of Long Range® (injectable Eprinomectin) and Zolvix® (oral Monepantel) in sheep and goats and to formulate a strategy for incorporating Long Range and Zolvix in TST of small ruminants. 2) to reduce exposure of susceptible GIN parasites to the drugs and greatly reduce development of anthelmintic resistance by a combination of novel control strategies for sustainable small ruminant GIN control in the U.S. using anthelmintics in TST, COWP and feeding of the high-tannin perennial legume Sericea lespedeza, and 3) to test integrated small ruminant GIN control on farms and widely distribute university and on-farm research results to clientele groups.
Controlling parasitic nematodes in small ruminants by exclusive use of chemical anthelmintics is no longer a viable approach due to widespread anthelmintic resistance in sheep and goat GIN. A more sensible, sustainable approach to controlling parasites is 1) to take steps to maximize effectiveness of anthelmintics through smart drenching techniques, 2) reduce exposure of susceptible parasites to the drugs (and greatly reduce development of anthelmintic resistance) by treating only those animals identified as needing treatment based upon the FAMACHA system of anemia detection, 3) utilize novel pasture management strategies that interrupts the parasite life cycle and enhance the animal's resistance or resilience to GIN infection and 4) using non-chemical control alternatives.Experiments will be conducted in different groups of adult sheep and goats in fall and spring of the year to evaluate the anthelmintic efficacy of Long Range® (LR) and Zolvix® (ZX). Animals will be permitted to acquire a natural GIN burden on pasture prior to the investigation. Sheep and goats will be given a single treatment of either LR or ZX in the respective groups of 10 animals in the pasture. All animals will be grouped and ranked by Fecal Egg Count (FEC) prior to treatments. Fecal Egg Count Reduction (FECR) tests will be conducted according to the method described in World Association for the Advancement of Veterinary Parasitology (WAAVP) guidelines for detection of anthelmintic resistance (Coles et al., 1992). A control group of 10 animals will be used for comparison with the treatment groups. In each experiment fecal samples will be collected per rectum from all animals on a weekly basis and trichostrongyle nematode Egg Per Gram (EPG) will be determined on all samples using a modified McMaster technique with a minimum sensitivity of 50 EPG (Henniksen and Aagaard, 1976) for approximately 120 days. Level of anemia will be monitored weekly using FAMACHA scoring system (1 = Red or healthy, 5 = White, or severely anemic). Animals will be weighed every 28 days. Composite fecal culture from five animals in each group will be formed for identification of worm species. Efficacy of dewormings and weight data will be evaluated statistically at the end of this phase for Objective 2 and formulating a strategy for incorporation of LR and ZX in TST of Small Ruminants in fall and spring.With data driven from experiments in objective 1, experiments will be conducted to evaluate COWP/LR, COWP/ZX, SL/LR, and SL/ZX, to evaluate their GIN infection control abilities in different combinations. These integrated approaches maybe a viable alternative to first starting a chemical deworming followed by subsequent treatments with COWP and/or SL when FEC reaches a determined threshold. FAMACHA would be used to determine when individual anthelmintic treatments are required.Following experiments in objectives 1 and 2, recommendations for TST will be formulated for use of the tested drugs. On farms with known resistance to commonly used anthelmintics, clinical trials with LR and ZX, along with non-chemical combinations will be tested based on formulated recommendations. Infection levels will be monitored with FAMACHA. Production costs and benefits (weight gain) will be recorded and analyzed.