Novel solutions for the sustainable control of nematodes in ruminants
Nematodes in ruminants – an ethical, economical and a health issue
Food quality and safety are basic requirements and important to all consumers regardless of the country where they live. Especially hygiene and chemical residues are a preoccupation for all consumers. One of the greatest threats to animal production worldwide is the occurrence of Gastro-intestinal nematode parasites in ruminants, as they lead to poor food quality, poor animal welfare and low profitability. Therefore, worm infections have to be controlled. Yet current methods of worm control, involving repeated dosing of whole herds with synthetic anthelmintics, are not sustainable in the short to medium term as they are known to cause a number of problems. Environmental and food residues build up, e.g., in meat and milk. Also, the spread of anthelmintic resistance (AR) to the drugs commonly used is rapidly promoted. Nevertheless, effective chemical anthelmintics remain irreplaceable for worm control, as other possibilities, such as vaccines which might provide a long-term solution, are still many years from the market.
New strategies - Targeted Selective Treatments (TST)
In order to conserve the efficacy of anthelmintics whilst reducing the incidence of helminthoses in livestock, and at the same time the residue build-up, the PARASOL Project aims at creating low input and sustainable programs for nematode control by developing strategies for Targeted Selective Treatment (TST). TST focuses on minimising the numbers of whole herd/flock anthelmintic treatments of ruminants by directing individual treatments towards those animals most susceptible to disease and/or responsible for most pasture contamination. The use of TST aims at minimising the use of anthelmintics, thus reducing any associated environmental and health risks, while maintaining agricultural productivity. The basic idea is simple, if one assumes that animals with a high worm burden show symptoms such as diarrhoea, emaciation, abdominal pain or reduced productivity, whereas animals with low worm burdens do not. With TST, only clinically suspicious animals are treated. If applied optimally, TST does not result in any significant production losses to farmers but may even produce economic benefits due to reduced drug costs. Also, the use of TST will maintain unselected populations of nematodes, thus reducing the selection pressure for the development of anthelmintic resistance by keeping a proportion of the parasite population in refugia (i.e., not exposed to the chemicals).
The difficulty is that the development of such treatment plans for sheep, goats and cattle requires detailed information on the best TST strategies for the use of different drugs in different geographical regions and for different farm animals as well as the determination of early indicators for affected animals. Examples of these indicators are: serum pepsinogen levels, bulk milk antibody levels, live-weight gains and body condition scoring in cattle or fertility, fecundity, milk yield and weight gains in sheep or goats.
Goals of the PARASOL Project
Within the three year program the Partners participating in the PARASOL Project will assess several innovative methods for identifying animals, flocks and herds that require anthelmintic intervention and will determine the effects of TST on productivity, animal welfare and the spread of anthelmintic resistance genes. These studies will be carried out on cattle, sheep and goats under various farming conditions. Also, the PARASOL Partners will standardise existing tests for anthelmintic resistance and develop further tests where those are not sufficient. At the same time the Partners aim to optimise the efficacy and bioavailability of anthelmintics commonly used.
By the end of the project, the PARASOL Partners plan to provide an innovative computer-supported decision system for identifying animals that require treatment as well as clear guidance and protocols for sustainable, low-input, user and consumer friendly farm plans on nematode control in ruminants for implementation in Europe and selected INCO target countries. These strategies will then be communicated to farmers, veterinarians, advisors and trained animal health technicians throughout the participating countries so that they can be incorporated into larger integrated, farm-to-fork production schemes for the production of healthy, safe and high-quality food as well as contribute toward maintaining a high standard of animal welfare. The results obtained in the PARASOL Project could also have an indirect impact on successful programmes for breeding parasite resistant animals.