Novel Methods for Sustainable Control of Gastrointestional Nematodes in Small Ruminants

Final Report for LS02-143

Project Type: Research and Education
Funds awarded in 2002: $254,137.00
Projected End Date: 12/31/2006
Region: Southern
State: Georgia
Principal Investigator:
Thomas Terrill
Fort Valley State University
Expand All

Project Information

Abstract:

Infection with gastrointestinal nematodes (GIN) is a primary constraint to profitable goat and sheep production in the southern US, Puerto Rico (PR), and the US Virgin Islands (USVI). The primary objectives of this project were to determine prevalence of anthelmintic resistance in small ruminant GIN throughout these regions, to educate producers as to the need to reduce dependence upon chemical dewormers, and to develop and test novel, non-chemical parasite control technologies. On-farm anthelmintic resistance tests were completed on sheep and goat farms in GA, FL, LA, AR, PR, and the USVI, with a high prevalence of resistance detected to most of the drugs currently available to control parasitic nematodes. Producer workshops were held in each participating region to disseminate information on parasite biology, proper use of anthelmintics (smart drenching), and targeted deworming using the FAMACHA system to identify only those animals in the herd or flock that actually require treatment. This technology, based upon color of the eyelid to detect level of anemia, was developed for use with sheep in South Africa, and was validated for use with sheep and goats in the southern USA, PR, and USVI as part of this project. The number of FAMACHA workshops held yearly is continuing to expand, and approximately 8000 FAMACHA cards have been sold for on-farm use to date, resulting in much less usage of chemical anthelmintics and lowering of deworming costs. Fact sheets on smart drenching and FAMACHA technology are posted on a project web site maintained by the Southern Consortium for Small Ruminant Parasite Control (SCSRPC.org). Novel GIN control techniques that were tested in sheep and goats in this project included use of nematode-trapping fungi, copper oxide wire particles (COWP) and forages containing condensed tannins (CT), specifically dried forms of sericea lespedeza. Each of these technologies were effective against small ruminant GIN, either reducing fecal egg counts and adult worm numbers, or improving blood packed cell volume (anemia score) compared to control treatments. Combinations of limited anthelmintic use (targeted deworming) and novel techniques in integrated small ruminant GIN control programs are needed and are still being tested.

Project Objectives:

1. Bring about immediate improvements in GIN control and subsequent productivity in small ruminant operations in the southern US and the USVI by disseminating current state-of-the-art knowledge and technology to producers
2. Investigate and implement the use of novel non-chemical approaches in integrated, sustainable control strategies of GIN in small ruminants
3. Determine the economic impact on the small ruminant industry of uncontrolled multi-drug resistant GIN.

Introduction:

Production of small ruminants (sheep and goats) is an attractive enterprise for farmers in the southern United States (US), Puerto Rico (PR), and the US Virgin Islands (USVI) due to the relatively low cost of breeding stock and high ethnic demand for small ruminant meat and milk products. Grazing small ruminants, in particular lambs and kids, are very susceptible to infection with gastrointestinal nematodes (GIN), which can cause severe economic losses in production and ultimately death of infected animals. Past excessive use of anthelmintics to control GIN has led to widespread anthelmintic-resistant GIN populations in goats and sheep. This is reducing productivity and health of the animals, while at the same time increasing treatment costs due to ineffective drugs. At present this unfortunate situation is creating an unsustainable economic environment for small ruminant farmers, forcing many to quit production despite continued high demand in the market. Without development and implementation of novel, sustainable strategies to effectively control GIN, this problem will continue to grow and threaten viability of small ruminant production in the southern US and USVI.

Novel GIN control technologies currently showing promise include biological control (BC) using the nematode-trapping fungus Duddingtonia flagrans, feeding of copper oxide wire particles (COWP) to parasitized animals in a bolus, and grazing or feeding condensed tannin (CT)-containing forages to goats and sheep. Use of these techniques, combined with more appropriate use of dewormer, is currently the best option to overcome the problem of GIN parasitism for small ruminant producers. Our goal with this project was to determine the extent of the prevalence of anthelmintic resistance in sheep and goat GIN in the southern USA and USVI, test the effectiveness of targeted deworming as a means of reducing small ruminant production costs while preserving the effectiveness of remaining anthelmintics, developing and testing novel, non-chemical control methods, and educating producers, extension agents, and other clientele groups in the application of these concepts on-farm. This strategy involved both on-farm screening for anthelmintic resistance to identify effective dewormers and scoring animals according to the FAMACHA eye chart (a system developed in South Africa for determining level of anemia) to identify those animals needing treatment. In addition, grazing and confinement trials with goats and sheep given boluses of COWP and/or the nematode-trapping fungus Duddingtonia flagrans and feeding trials with sericea lespedeza hay were initiated as part of this project.
A multi-disciplinary team of farmers, extension personnel, leaders of small ruminant commodity organizations, and scientists from Georgia (GA), Florida (FL), Louisiana (LA), Arkansas (AR), the USVI, Puerto Rico (PR), Denmark, and South Africa participated in this project, meeting regularly (2 x per year) throughout the project period to review and plan research and extension/education activities. Farmer and extension officer training workshops on strategic use of anthelmintics and the FAMACHA eye chart were conducted in each state/region. Updates and research findings from the work were disseminated to end-users via a quarterly newsletter and an internet web site, extension-type publications in each state/region, and international scientific journals. This project is having a significant impact on profitability of small ruminant production in the southern USA and USVI due to reduced drug costs and improved animal health. Long-term, we expect this work to lead to integrated, sustainable approaches for GIN control in small ruminants and to provide the cornerstone for more secure, sustainable, growing small ruminant production in the southeastern USA, PR, and USVI.

Cooperators

Click linked name(s) to expand
  • Joan M. Burke
  • Will R. Getz
  • Timothy D Hewitt
  • Ray M. Kaplan
  • Michael Larsen
  • James E. Miller
  • Seyedmehdi Mobini
  • Jorge Mosjidis
  • Elide Valencia
  • Adriano Vatta
  • Mimi Williams
  • Lisa H. Williamson
  • Anne Zajak

Research

Materials and methods:

Objective 1.

Producer workshops on ‘smart drenching’ and FAMACHA were initiated during year 1 of the project (2003), in GA and FL. The workshops were extended to other participating regions (LA, AL, AR, OK, TX, PR, USVI) in year 2, with new areas added each year since. In 2006, there were at least 83 workshops held throughout the USA, with approximately 2500 FAMACHA cards sold for on-farm use. Since the first workshops were held in spring, 2003, over 190 workshops have been held, with over 8000 cards sold. At each workshop, participants are provided general information on parasite biology and management, techniques to improve the efficacy of anthelmintic use (smart drenching), and hands-on training in targeted deworming techniques, including use of the FAMACHA card to identify anemic animals. Producers are also given updates on novel, non-chemical control techniques as they are validated with research.
A producer survey on parasite control practices, animal numbers, and production information was developed and distributed to sheep and goat producers throughout the southern USA, PR, and the USVI as part of this project. The survey information was utilized to identify participants in on-farm research aspects of the project, including anthelmintic resistance, FAMACHA validation, and establishment of sericea lespedeza for hay and grazing. Survey data was also utilized in the write-up and publication of on-farm technique validation work.
A project web site (SCSRPC.org) was initiated in 2004 and regularly updated with profiles of project participants, fact sheets on GIN control techniques, a copy of our small ruminant parasite control and general management survey instrument, access to workshop presentations, and announcements for upcoming workshops, etc. Information on the project was published regularly in the Georgia Small Ruminant Research and Extension quarterly newsletter and the Land Grant Focus, both of which are published by the Extension Communications Department at Fort Valley State University.

Objective 2.

A series of experiments with confinement-fed and grazing sheep and goats were completed at collaborating institutions as part of this project to evaluate nematode-trapping fungi, copper oxide wire particles (COWP), feeds containing Tasco, a seaweed extract, and sun-dried sericea lespedeza, a high-tannin legume. For the nematode-trapping fungi studies, spores of Duddingtonia flagrans were mixed with a feed supplement and fed daily to parasitized sheep and goats in confinement or on pasture. For the COWP studies, the particles were placed into gel capsules and given to animals as a 1-time dose, while Tasco (5%) and sericea lespedeza (75%) were fed to sheep and goats as part of a complete ration. Dose titration studies with different levels of D. flagrans, COWP, and sericea lespedeza hay in the diet were also completed. In each study, efficacy of the treatments were evaluated by weekly fecal samples to determine fecal egg count (FEC) and to make fecal cultures to develop larvae for speciation purposes. Blood samples were taken weekly from all animals to determine pack cell volume (PCV), while animals were slaughtered to allow recovery, counting, and speciation of adult worms from the abomasum and small intestines when feasible.

Objective 3.

Projects related to objective 3 included on-farm evaluation of anthelmintic resistance in sheep and goat herds throughout the southern USA, PR, and the USVI, and validation of the FAMACHA system of anemia detection. Anthelmintic resistance evaluation included both in vivo (fecal egg count reduction) and in vitro (larval development assay) tests. The FAMACHA system was validated by correlating anemia scores on the card (from 1 = red, healthy, to 5 = white, severely anemic) to actual anemia levels in the animal as measured by blood PCV values. Data was collected from sheep and goat farms throughout the southern USA, PR, and the USVI initially to test and validate the FAMACHA instrument, and then to test farmer adoption of the system. Preliminary economic analyses were completed on these data in the form of cost savings for reduced use of anthelmintic drugs. Models to determine long-term economic benefits of reduced rate of development of anthelmintic resistance in combination with over-all reduced drug use are still being developed.

Research results and discussion:

The FAMACHA system was successfully validated for use in both sheep and goats in the southern US and USVI and has been readily accepted by producers throughout these regions. A large number of sheep and goat farmers, veterinarians, and county extension agents have been trained in the proper use of the FAMACHA card at nearly 200 workshops in 38 different states. The effectiveness of this training with producers was measured in a follow-up to the validation work, and the results were very positive, all of the participating producers accurately predicting parasite burdens in individual animals. This simple tool has the potential to greatly reduce anthelmintic use by sheep and goat farmers, and many producers have reported this reduction to be up to 90%.

Some level of parasite resistance to the action of chemical anthelmintics was found in sheep and goats for virtually all of the drugs currently available to producers. Many herds and flocks were found to have multiple anthelmintic resistance, which is resistance to drugs from 2 or more of the major drug families. Development of new drug resistance in previously susceptible nematode populations can occur very quickly (in less than two years) with small ruminants, and this was observed in the on-farm resistance testing undertaken as part of this project. Prevalence of resistance in sheep and goat herds was very high in all of the areas tested, despite differences in climate, vegetation, animal species or breed, and management styles.

Duddingtonia flagrans reduced FEC in both sheep and goats by approximately 80% or higher when fed in confinement or to animals on pasture. Pasture infectivity (larvae/g of plant material) was also reduced in grazing trials, but animal production parameters were not affected. Although this technology has excellent potential to reduce pasture infection rates, a major drawback is the need for daily feeding of the spores and a reliable source of the fungus. This research was discontinued due to these constraints, but the technique is still of value as one of the very few methods that targets the larval phase of the parasite life cycle, which could greatly impact small producers with limited access to clean (parasite-free) pastures. The Danish company originally supplying the D. flagrans spores is no longer pursuing this technology, but an Australian company is continuing to develop the method, including improved spore delivery methods. Our research group is in contact with the company and will resume the research when spores are made available.

Copper oxide wire particles have shown excellent potential to kill adult worms, specifically Haemonchus contortus, a blood-feeder that is by far the most pathogenic gastrointestinal nematode in the tropics and subtropics throughout the world. Although the exact mechanism of control is still unclear, giving COWP to lambs and kids reduces FEC up to 90% or higher and greatly improves PCV scores. There is potential for copper toxicity with sheep, so it is currently recommended not to give more than two doses of COWP per season. The trace mineral bolus containing copper reduced FEC and improved PCV in older animals (ewes and does), but it is not appropriate for young stock because of the size of the bolus.

Sun-dried sericea lespedeza (hay) in long, ground, and pelleted forms showed very high efficacy against gastrointestinal nematode infection in both sheep and goats, as measured by lower FEC, higher PCV, and lower adult worm numbers in the abomasum and small intestines. The reduction in FEC in animals fed the different forms of SL hay ranged from 60-98%, while adult H. contortus numbers were reduced by up to 75%.

Participation Summary

Educational & Outreach Activities

Participation Summary

Education/outreach description:

Refereed Journal Manuscripts

Terrill, T.H., J.A. Mosjidis, D.A. Moore, S.A. Shaik, J.E. Miller, J.M. Burke, J.P. Muir, and R.Wolfe. 2007. Effect of pelleting on efficacy of sericea lespedeza hay as a natural dewormer in goats. Veterinary Parasitology (In press).

Kaplan, R.M., A.N. Vidyashankar, S.B. Howell, J.M. Neiss, L.H. Williamson, and T.H. Terrill. 2007. A novel approach for combining the use of in vitro and in vivo data to measure and detect emerging moxidectin resistance in gastrointestinal nematodes of goats. International Journal for Parasitology (In press).

Burke, J.M, T.H. Terrill, R.R. Kallu, J. E. Miller, and J. Mosjidis. 2007. Use of copper oxide wire particles to control gastrointestinal nematodes in goats. Journal of Animal Science (Accepted for publication).

Burke, J.M., R.M. Kaplan, J.E. Miller, T.H. Terrill, W.R. Getz, S. Mobini, E. Valencia, M.J. Williams, L.H. Williamson, and A.F. Vatta. 2007. Accuracy of the FAMACHA system for on-farm use by sheep and goat producers in the southeastern United States. Veterinary Parasitology (In press).

Bath, G.F. 2006. Practical implementation of holistic internal parasite management in sheep. Small Ruminant Research 62:13-18.

Shaik, S.A., T.H. Terrill, J.E. Miller, B. Kouakou, G. Kannan, R. M. Kaplan, J.M. Burke, and J. Mosjidis. 2006. Sericea lespedeza hay as a natural deworming agent against gastrointestinal nematode infection in goats. Veterinary Parasitology 139:150-157.

Lange, K.C., D.D. Olcott, J.E. Miller, J.A. Mosjidis, T.H. Terrill, J.M. Burke, and M.T. Kearney. 2006. Effect of sericea lespedeza, fed as hay, on natural and experimental Haemonchus contortus infections in lambs. Veterinary Parasitology 141, 273-278.

Burke, J.M., and J.E. Miller. 2006. Evaluation of multiple low doses of copper oxide wire particles compared with levamisole for control of Haemonchus contortus in lambs. Veterinary Parasitology 139:145-149.

Burke, J.M., and J.E. Miller. 2006. Control of Haemonchus contortus in goats with a sustained-release multi-trace element/vitamin ruminal bolus containing copper. Veterinary Parasitology 141:132-137.

Burke, J.M., J.E. Miller, M. Larsen, and T.H. Terrill. 2005. Interaction between copper oxide wire particles and Duddingtonia flagrans in lambs. Veterinary Parasitology 134:141-146.

Burke, J.M., J.E. Miller, and D.K. Brauer. 2005. The effectiveness of copper oxide wire particles as an anthelmintic in pregnant ewes and safety to offspring. Veterinary Parasitology 131:291-297.

Terrill, T.H., M. Larsen, O. Samples, S. Husted, J.E. Miller, R.M. Kaplan, and S. Gelaye. 2004. Capability of the nematode-trapping fungus Duddingtonia flagrans to reduce infective larvae of gastrointestinal nematodes in goat feces in the southeastern United States: dose titration and dose time interval studies. Veterinary Parasitology 120:285-296.

Kaplan, R.M., J.M. Burke, T.H. Terrill, J.E. Miller, W.R. Getz, S. Mobini, E. Valencia, M.J. Williams, L.H.Williamson, M. Larsen, and A.F. Vatta. 2004. Validation of the FAMACHA© eye color chart for detecting clinical anemia in sheep and goats on farms in the southern United States. Veterinary Parasitology 123:105-120.

Shaik, S.A., T.H. Terrill, J.E. Miller, B. Kouakou, G. Kannan, R.K. Kallu, and J.A. Mosjidis. 2004. Effects of feeding sericea lespedeza hay to goats infected with Haemonchus contortus. South African Journal of Animal Science 34 (1):248-250.

Kaplan, R.M. 2004. Drug resistance in nematodes of veterinary importance: a status report. Trends in Parasitology 20(10): 477-481.

Mortensen, L.L., L.H. Williamson, T.H. Terrill, R.A. Kircher, M. Larsen, and R.M. Kaplan. 2003. Evaluation of prevalence and clinical implications of anthelmintic resistance in gastrointestinal nematodes in goats. JAVMA 223: 495-500.

Papers Published in Conference Proceedings

Dykes, G.S., Terrill, T.H., Shaik, S.A., Miller, J.E., Kouakou, B., Kannan, G., Burke, J.M., Kaplan, R.M., Mosjidis, J.A., 2006. Effect of sericea lespedeza hay on gastrointestinal nematode infection in goats. Proceedings of the American Forage and Grassland Council 15: 245-249.

Shaik, S.A., T.H. Terrill, J.E. Miller, B. Kouakou, G. Kannan, R.M. Kaplan, J.M. Burke, and J.A. Mosjidis. 2005. Anthelmintic effects of sericea lespedeza hay fed to goats infected with Haemonchus contortus. Proceedings of the XX International Grassland Congress, 26 June – 6 July, 2005, Dublin, Ireland.

Miller, J.E., J.A. Stuedemann, and T.H. Terrill. 2005. Nematode parasites and grazing research. Proceedings of the 59th Southern Pasture and Forage Crop Improvement Conference, 11-13 May 2005, Philadelphia, MS.

Terrill, T.H., and J.E. Miller. 2005. Nematode parasites in small ruminant grazing research: Changing perspectives. Proceedings of the 59th Southern Pasture and Forage Crop Improvement Conference, 11-13 May 2005, Philadelphia, MS.

Burke, J.M., and J.E. Miller. 2004. Effects of grazing endophyte-infected or novel endophyte-infected tall fescue on gastro-intestinal nematodes in sheep and cattle. 5th International Symposium on Neotyphodium/Grass Interactions 2004; no. 413.

Kaplan, R.M. 2004. Responding To The Emergence of Multiple-Drug Resistant Haemonchus contortus: Smart Drenching and FAMACHA®, in Proceedings of the Georgia Veterinary Medical Association 2004 Food Animal Conference, Tifton Bull Evaluation Center, Irwinville, Georgia, March 6 – 7, 2004.

Kaplan, R.M. 2004. Parasites, Their Resistances and Alternate Methods, in Proceedings of the 7th World Sheep and Wool Congress, Quebec, Canada, July 17-24, 2004.

Kaplan, R.M., 2004. Responding To The Emergence of Multiple-Drug Resistant Haemonchus contortus: Smart Drenching and FAMACHA®, in Proceedings of the Kentucky Veterinary Medical Association/31st Annual Mid-America Veterinary Conference, Louisville, Kentucky, October 8 10, 2004.

Producer-oriented Publications:

Burke, J.M, J.E. Miller, and T.H. Terrill. 2007. Use of copper oxide wire particles (COWP) to control barber pole worm in lambs and kids. www.scsrpc.org.

Shaik, A.S., and T.H. Terrill. 2005. “Sericea lespedeza hay: Ready to accept the challenge from Haemonchus contortus.” Georgia Small Ruminant Research and Extension Center Newsletter, Winter 2005.

Kaplan, R.M. 2004. Parasite control: A new way of thinking, Goat Rancher, June 2004, pp. 11-21.

Kaplan, R.M. 2004. Responding To The Emergence of Multiple-Drug Resistant Haemonchus contortus: Smart Drenching and FAMACHA®, Icelandic Sheep Breeders of North America Newsletter, Summer 2004, Vol. 8(3), pp. 18-23.

Terrill, T.H. 2004. Nematode wars: FVSU assembles parasite control team. p. 1-2. In Georgia Small Ruminant Research and Extension Center Newsletter, Winter 2004.

Abstracts

Moore, D.A, T.H. Terrill, S.A. Shaik, J.E. Miller, J.M. Burke, J.P. Muir, R. Wolfe, and
J.A. Mosjidis. 2007. Effect of pelleting on anthelmintic efficacy of sericea lespedeza hay against gastrointestinal nematodes of goats. Journal of Animal Science 2007 (Supplement 2): (Abstract).

Chafton, L.A., J.E. Miller, J.A. Mosjidis, T.H. Terrill, and J.M. Burke. The effect of sericea lespedeza, fed as ground hay, on existing and establishing infection of Haemonchus contortus in sheep. Journal of Animal Science 2007 (Supplement 2): (Abstract).

Burke, J.M, J.E. Miller, T.H. Terrill, and J.A. Mosjidis. 2007. Interaction between copper oxide wire particles and grazing sericea lespedeza to control gastrointestinal nematodes in goats. Journal of Animal Science 2007 (Supplement 2): (Abstract).

Burke, J.M., J.E. Miller, and T.H. Terrill. 2007. Interaction between high protein supplement and copper oxide wire particles to control gastrointestinal nematodes in growing goats. Journal of Animal Science 2007 (Supplement 2): (Abstract).

Burke, J.M., J.E. Miller, and T.H. Terrill. 2007. Low dose titration of copper oxide wire particles for control of gastrointestinal nematodes in weaned kids. Journal of Animal Science 2007 (Supplement 2): (Abstract).

Terrill, T.H., J.E. Miller, and J. Muir. 2006. Use of forages as a natural method of controlling parasitic nematodes of livestock. American Society of Agronomy International Meeting, November 12-16, 2006, Indianapolis, IN.

Terrill, T.H., G.S. Dykes, S.A. Shaik, J.E. Miller, B. Kouakou, G. Kannan, J.M. Burke, R.M. Kaplan, and J.A. Mosjidis. 2006. Controlling gastrointestinal nematode infection in goats using sun-dried forage high in condensed tannins. Proceedings of the 51st American Association of Veterinary Parasitologists Meeting, July 15-18, 2006, Honolulu, HI.

Chafton, L.A., JE. Miller, J.A. Mosjidis, T.H. Terrill, and J.M. Burke, 2006. The effect of the condensed tannin containing forage sericea lespedza fed as a meal on existing and establishing infection of Haemonchus contortus in sheep. Proceedings of the 51st American Association of Veterinary Parasitologists Meeting, July 15-18, 2006, Honolulu, HI.

Muir, J.P., E. Valencia, S. Weiss, and T.H. Terrill. 2006. Small ruminants for biological control of invasive weeds. P. 77. Caribbean Food Crops Society 42nd Annual Meeting, July 9-14, 2006, San Juan Puerto Rico.

Terrill, T.H., W.F. Whitehead, B.P. Singh, S. Gelaye, R.G. Durham, and C.S. Hoveland. 2005. Preference of grazing goats for cool-season annual clovers. Abstracts of the Southern Section ASAS Meetings, Little Rock, AR, page 18.

Burke, J.M., J.E. Miller, M. Larsen, and T.H. Terrill. 2005. Interaction between copper oxide wire particles (COWP) and Duddingtonia flagrans in hair breed lambs. Abstracts of the Southern Section ASAS Meetings, Little Rock, AR, page 15.

Lange, K., D. Olcott, J.E. Miller, J.A. Mosjidis, T.H. Terrill, and J.M. Burke. 2005. Effect of the condensed tannin-containing forage, sericea lespedeza, fed as hay, on natural and experimental challenge infection in lambs. Abstracts of the Southern Section ASAS Meetings, Little Rock, AR, pages 15-16.

Shaik, S.A., T.H. Terrill, J.E. Miller, B. Kouakou, G. Kannan, R.M. Kaplan, J.M. Burke, and J.A. Mosjidis, 2005. Effects of feeding sericea lespedeza hay to goats infected with Haemonchus contortus. Abstracts of the Southern Section ASAS Meetings, Little Rock, AR, page 3.

Kallu, R.K., T.H. Terrill, and J.E. Miller. 2005. Efficacy of copper oxide wire particles against gastrointestinal nematodes of goats. Abstracts of the Southern Section ASAS Meetings, Little Rock, AR, page 4.

Miller, J.E., J.M. Burke, and T.H. Terrill. Effect of 0.5, 1.0, and 1.5 gram copper oxide wire particles on natural infection in lambs. Abstracts of the Southern Section ASAS Meetings, Little Rock, AR, page 15.

Burke, J.M., J.E. Miller, M. Larsen, and T.H. Terrill. 2005. Interaction between copper oxide wire particles (COWP) and Duddingtonia flagrans in hair breed lambs. 4th International Conference on Novel Approaches to the Control of Helminth Parasites of Livestock, 10-12 January, 2005, Merida, Yucatan, Mexico, page 24.

Shaik, S.A., T.H. Terrill, J.E. Miller, B. Kouakou, G. Kannan, R.M. Kaplan, J.M. Burke, and J.A. Mosjidis. 2005. Effects of feeding sericea lespedeza hay to goats infected with Haemonchus contortus. 4th International Conference on Novel Approaches to the Control of Helminth Parasites of Livestock, 10-12 January, 2005, Merida, Yucatan, Mexico, page 37.

Lange, K.C., D.D. Olcott, J.E. Miller, J.A. Mosjidis, T.H. Terrill, and J.M. Burke. 2005. Effect of the condensed tannin containing forage, sericea lespedeza, fed as hay, on natural and experimental challenge infection in lambs. 4th International Conference on Novel Approaches to the Control of Helminth Parasites of Livestock, 10-12 January, 2005, Merida, Yucatan, Mexico, page 38.

Shaik, S., T.H. Terrill, J.E. Miller, B. Kouakou, G. Kannan, R. Kallu, and J.A. Mosjidis. 2004. Effects of feeding sericea lespedeza hay on goats infected with Haemonchus contortus. Abstracts of the AAVP/ASP/AVMA 2004 Joint Meeting, July 24-28, 2004, Philadelphia, PA., page 40.

Kallu, R, T.H. Terrill, J.E. Miller, S.R. Maddineni, S. Shaik, and J.M. Burke. 2004. Efficacy of copper oxide wire particles against Haemonchus contortus in goats. Abstracts of the AAVP/ASP/AVMA 2004 Joint Meeting, July 24-28, 2004, Philadelphia, PA., pages 40-41.

Kaplan, R.M., J. Neiss, L.H. Williamson, and T.H. Terrill. 2004. Moxidectin resistance in gastrointestinal nematodes of goats in Georgia. Abstracts of the AAVP/ASP/AVMA 2004 Joint Meeting, July 24-28, 2004, Philadelphia, PA., pages 55-56.

Miller, J.E., J.M. Burke, D.D. Olcott, B.M. Olcott, and T.H. Terrill. 2004. Effect of copper oxide wire particle dosage on Haemonchus contortus infection in lambs. Abstracts of the AAVP/ASP/AVMA 2004 Joint Meeting, July 24-28, 2004, Philadelphia, PA., page 50.

Terrill, T.H., J.E. Miller, R.M. Kaplan, M. Larsen, R.A. Kircher, O.M. Samples, and S. Gelaye. 2004. Epidemiology of gastrointestinal nematodes of goats in Georgia. Abstracts of the AAVP/ASP/AVMA 2004 Joint Meeting, July 24-28, 2004, Philadelphia, PA, page 89.

Shaik, S.A., T.H. Terrill, J.E. Miller, B. Kouakou, G. Kannan, R.K. Kallu, and J.A. Mosjidis. 2004. Effects of feeding Sericea lespedeza hay to goats infected with Haemonchus contartus. Abstracts of the Eighth International Conference on Goats, Pretoria, South Africa, page 80.

Mweemba, C., R. Eckhart, G. Kannan, R. A. Kircher, and T.H. Terrill. 2003. Effect of gastrointestinal nematode infection on stress responses in goats. Abstracts of the Thirteenth Biennial Research Symposium of the Association of Research Directors, Inc., Atlanta, GA, page 43.

Project Outcomes

Project outcomes:

This work is continuing to increase awareness of producers, veterinarians, extension agents, and scientists as to the seriousness of the problem of anthelmintic resistance in small ruminant GIN. This has been indicated by the overwhelming acceptance and adoption of the FAMACHA system by producers, which has caused a dramatic reduction in the use of chemical anthelmintics by a large number of sheep and goats producers in the USA, Puerto Rico, and the US Virgin Islands. This is helping to sustain the small ruminant industry in these regions by saving producers money through reduced drugs expenditures. Using the FAMACHA system has also allowed producers to improve herd or flock genetics for resistance and resilience to parasitic infection by allowing culling of highly susceptible animals. Another impact of this work is the increased acceptance by producer of alternative (novel) strategies to control parasitic infection in sheep and goats, and the need for combinations of strategies instead of just waiting for the next anthelmintic ‘silver bullet’ to come along. This has been demonstrated in an increased number of visitors to our project web site (over 30,000 in 2006) and a greatly increased volume of calls from producers inquiring about the use of copper oxide wire particles and sericea lespedeza as anti-parasitic agents.

Economic Analysis

Preliminary economic analysis suggests that producers implementing the FAMACHA system reduce their drug costs by 70% or more while potentially improving herd or flock genetics for resistance. Exact dollar amounts are difficult to assess due to widely variable drug costs. However, using Cydectin sheep drench as an example, which costs approximately $1.00 per treatment per animal (goat dose), if a producer with 100 breeding does normally deworms 4 x per year, his drug costs for the doe herd alone would be $400.00 per year. Through using the FAMACHA system, his anthelmintic costs would be reduced by $280.00 per year or more.

Farmer Adoption

Producers have increased their awareness of the need for anthelmintic resistance testing on individual farms and targeted deworming of only those animals in the herd or flock most heavily parasitized. Evidence of the former is the number of producers requesting an larval development assay (LDA) assessment of the level of anthelmintic resistance in their herd or flock (Nearly 100 over 5 years), while close to 200 FAMACHA workshops have been held throughout the US, PR, and USVI, with over 8000 FAMACHA cards sold for targeted deworming since the system was introduced into the USA in 2003. Evidence of producer adoption of the novel GIN control techniques successfully tested during this project include a sharp increase in email and phone requests for information about copper oxide wire particles and sericea lespedeza planting and management. The company that markets AUGrazer sericea lespedeza, Sims Brothers, Inc., of Union Springs, Alabama, sold out their supply of lespedeza seed this year for the first time in several years. An indication of the general interest in this work is the number of visitors to our project web site, which is growing each year, with over 30,000 hits in 2006 alone.

Recommendations:

Areas needing additional study

The main areas needing additional study include more in depth analysis of the economic impact of the FAMACHA system on-farm, as well as the use of copper oxide wire particles and dried or grazed sericea lespedeza to control small ruminant GIN. Additional research is needed in looking at effectiveness of combinations of FAMACHA with novel, non-chemical control technologies in conventional and organic sheep and goat farming systems. Additional study of the effectiveness of producer education and ‘train the trainer’ courses in integrated parasite control is needed as well.

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.