Background

Small ruminant livestock are important elements of the pathway out of poverty for millions of the rural poor in Asia and the Pacific. All livestock have a special role to play in the conversion of feed that is unsuitable for humans into food and other useful products, but small livestock, such as goats and sheep, are especially important for the poorest livestock keepers and for the landless who could start to raise livestock.

Helminth parasites are important for two reasons. First, their impact on health reduces the level of output of meat, milk and manure, and reduces asset value though increased mortality, especially of young stock. Second, a sustainable approach to the control of gastrointestinal nematodes of goats and sheep has been to integrate many interventions, involving feeding, breeding, grazing management and health control. Thus, this project (IFAD Technical Assistance Grant No. 443) on integrated control of nematode helminths in goats in Southeast Asia has become a springboard for a wide range of improvements in goat production, driven mainly by a reduction in mortality and better use and management of local resources.

The explanation for this may lie in the biology of some helminths, whose life cycles are very closely linked to the nutrient cycle in a grazing system. Good management of the nutrient cycle may simply lead to good management of parasites transmitted by parasitic larvae or cysts in the feed supply. Alternatively, it is possible that an integrated and holistic approach to any of the major constraints facing livestock production, for example, quality and quantity of feed, endemic and epidemic diseases, inadequate access to markets, may lead to overall improvements in productivity and security. Success may be as closely linked to the approach to the problem as it is to effectiveness of the technical components in the solution.

An integrated approach to worm control in goats

Approximately 10% of the world’s sheep and 29% of the world’s goats are to be found in Southeast Asia. Haemonchosis, a disease caused by blood-sucking stomach worms, has been identified as the most serious endoparasite constraint on small ruminant production in Southeast Asia. It is difficult to combat this disease, as conventional parasite control with drugs is affected by increased anthelmintic resistance. Modern control methods, e.g. an investigation of host genetic resistance, are promising tools, but benefits will take some time to realize. Rapid recognition of anthelmintic resistance at an early stage in its development is the key to the formulation of recommendations for the better use of anthelmintics, e.g. strategic drenching. This ensures also that quarantine recommendations can be developed in a timely manner to minimize the spread of resistant parasites to areas that have not yet been infected.

The starting point for this project was to develop breeds of goats and sheep in Southeast Asia that had genetic resistance to nematode infections, and to develop better methods for the detection of anthelmintic resistance. This built on successful research in a number of tropical countries, where breed differences had been demonstrated in sheep and goats, and on research on the detection of resistance in Australia. The concept was to develop resistant genotypes and then integrate this genetic component into a comprehensive control programme that made intelligent use of chemicals. However, as ideas were discussed among the research group over many months, two major changes to the concept emerged.

First, it was agreed that there had been sufficient research on a number of options for worm control in sheep and goats to enable a group of ‘experts’ to design effective control programmes without waiting for new genetic information. These “best-bet” options (including systematic drenching, rotational grazing and use of medicated feed blocks) would be validated with farmers as needed and, as new data became available and new options developed, these would be added to the mix of control measures.

The second conceptual change was based on the simple observation that over many years there have been many technologies developed for worm control in large and small ruminants, but that the uptake of these technologies was very low. A classic example is the drenching of buffalo calves at 2 weeks of age to completely break the life cycle of T. vitulorum. It then became a clear objective of the group to understand why there was so little adoption. One immediate conclusion was that farmers had to be intimately involved in the research and development of possible control programmes. It was concluded that no technologies could be effective without an understanding of the real needs of small-ruminant farmers.

Thus the thrust of this project, and a regional objective of ILRI, became research into appropriate technologies, and implementing the research with the participation of the full range of partners (Figure 1). These partners are the farmers, extension workers, biological, social and economic scientists, government officials and investors, whose support and commitment are needed to develop an effective programme that removes internal parasites as a constraint on production. The end product may not be a control programme in the conventional sense, but a set of changes that minimizes the impact of worms on mortality, income and the livelihood of farmers.

A working definition of sustainable parasite control (SPC) has been developed in a number of workshops and discussions. SPC:

• is an approach combined with a set of technologies (Figure 2);
• includes grazing management, nutrition, deworming, breeding, housing, and additional technologies as they become available from applied research;
• requires farmer and researcher to work and learn together, with good information and tools (Figure 3);
• is directed at improving income and security of livestock keepers; and
• does not rely on any single control measure.

Grant purpose

The objectives were to:

• reduce poverty amongst smallholder farmers in south and Southeast Asia through the improvement of small ruminant productivity; and
• promote the sustainable use of integrated parasite control and establishment of a participatory process to solve problems associated with endemic livestock disease.

Components

Studies and assessment

Available information on methods of use and application of anthelmintics, management practices and nutrition as a mean of controlling worm parasites in small ruminants were assessed. A diagnostic survey of the causes of continued mortality of goats was undertaken;

SPC strategies available in tree–livestock and crop–livestock production systems in the rainfed ecological zones of Southeast Asia were further developed and tested. Testing included SPC options as “best-bet” practices, including ex ante economic impact studies involving trials on the economic effects of infection in sheep and goats.

The technical options included in the current programme in the Philippines include:

• Use of effective chemicals, incorporating knowledge on anthelmintic resistance and use of alternative delivery methods, such as feed blocks. Quarantine drenching is an appropriate strategy for institutions and large commercial suppliers of stock.
• Improved nutrition, including the use of tree and shrub leaves to reduce intake for ground-based and contaminated feeds; plants with possible direct or indirect anthelmintic effect; and cut-and-carry methods, especially during times of heavy rain or heavy pasture contamination.
• Grazing management addresses improved housing to reduce stress through better ventilation, shelter (Figure 4), manure and feed management (Figure 5), rotational grazing and management of contaminated areas around housing.
• Controlled breeding includes timing of breeding to have young susceptible kids and lambs when worms can be best managed; and considering possible increase or decrease in genetic resistance when deciding to use new genetic inputs, especially ‘upgraded’ or ‘improved’ bucks and rams.
  All of these options are based on experimentation that has been conducted with farmers, extension workers and local scientists. If new technologies, such as vaccines, selective breeding, biological control and other ‘upstream’ methodologies can meet the needs of small-scale farmers who have restricted access to innovations, limited cash for inputs and a wide range of uses for their goats and sheep, then it would an interesting addition to the basket of technology options available for worm control.
• Adaptation and improvement of an existing computer model for use by research and extension agencies in assessing worm control options in different agro-ecological zones and farming systems in the tropics. A computer model called Wormworld, developed in Australia to assess the impact of resistance to anthelmintics on the control of worm parasites on pasture-based systems, was adapted to the requirements of animal husbandry in the target regions. A further objective was to adapt the model to non-pasture-based systems.
  ? Capacity building was undertaken through on-farm research activities and training for villagers, covering the various SPC options, in order to develop a cadre of auxiliary extension workers, village vaccinators and veterinary auxiliaries.
• Workshops with training, planning and review components were organized at the beginning of the programme, and planned for the end of project activities.

Impact

The programme is ongoing, and significant recent activities include:

• continuing the development of “Tropical Wormworld” – an epidemiological model for the control of the major nematodes parasites of small ruminants in Southeast Asia;
• creation of the web-ready interface for Tropical Wormworld;
• development of the Sustainable Parasite Control for Small Ruminants (SPC database), with 1 415 bibliographic records (794 records with abstract) so far;
• distribution of the SParC Information System (SIS) CD;
• completion of reviews of data for Thailand, Fiji, the Philippines, and Indonesia, and in progress for Malaysia, Nepal and Viet Nam;
• preparation of Project Working Papers;
• completion of workshops on Train the Trainers and Laboratory Diagnosis of Resistance to Helminths in the Philippines;
• completion of a Planning Workshop in Lao PDR in September 2001;
• a meeting of national liaison officers to discuss the project logframe and supervision mission outcomes;
• participation of five project staff in the Participatory Research and Development Training Course of CIP-Upward;
• completion of the first assessment of small ruminant production systems in Cambodia;
• an assessment of opportunities for SPC in Nepal;
• selection of communities following participatory diagnosis in the Philippines, Indonesia, Viet Nam and the Lao PDR;
• Community Action Planning and training for farmers and local extension workers in technology options and participatory methods in the Philippines, Indonesia and Viet Nam;
• selection, experimentation and validation of technology options at three sites in the Philippines; and
• monitoring and evaluation of the project in all countries, and social, economic and biological evaluation at the three sites in Pangasinan and Cebu in the Philippines.