An Integrated Parasite Control Framework for Ruminants

Parasites, if they are not controlled effectively, have a major impact on the productivity, health and welfare of sheep and cattle. Cattle and sheep pick up parasites, such as roundworms, whilst they graze. These parasites are normally controlled by treating the whole flock or herd with a worming medicine that either prevents infection or that kills the parasites before they cause damage. However, this type of approach to parasite control has resulted in the development of resistance to the medicines used, meaning the parasites are no longer killed by the treatment. In this project we will identify ways in which the control of parasitic diseases could be improved to reduce the impact and spread of resistance. We will focus on roundworm parasites found in the stomach and intestines of sheep, since anthelmintic resistance is prevalent in sheep roundworm populations, and it is a growing threat to the sheep industry in the UK.

To achieve this aim we will first establish in partnership with farmers, vets and Registered Animal Medicine Advisors, what farmers need enable them to integrate new parasite control strategies on their farms. Secondly, using mathematical models, we will identify new options that could be used to improve parasite control on farms. These models will build on existing mathematical models and develop them further to include farm and stock management data together with parasite burdens within individual animals. In this way the impact on parasite burden of specific interventions such as selecting heavily parasitised individual animals to treat or changing to a mob-based pasture management system can be assessed before they are rolled out onto farms.

The outputs from the project will be a better understanding of what inhibits farmers from adopting new approaches to parasite control and secondly will present new options that could be used on farms to improve parasite control.

Parasitic diseases are ubiquitous and compromise the health, productivity and welfare of farmed animals. Such diseases are currently controlled using chemoprophylactic programmes, but this practice has led to the emergence of resistance to anti-parasite medicines. Anthelmintic resistance (AR) has been reported in UK to all but one of the major classes of anthelmintic and multi-drug resistance is prevalent. AR has been identified by the industry as one of the top disease/syndromes impacting on sheep and cattle in the UK and is seen as the biggest challenge to the future profitability of the sheep farming sector. In this proof-of-concept project, we will focus on sheep production systems in the UK and gastro-intestinal nematode (GIN) infections that cause parasitic gastro-enteritis (PGE).
We will work with farmers, RAMA and vet focus groups across the UK, to identify current practices around helminth control in sheep flocks and to identify impediments to sustainable parasite control. We will address issues around parasite diagnosis prior to treatment and what impedes their use.
We will use high level mathematical agent based systems model that can be interrogated to address the effectiveness of different control interventions at a farm level whilst including individual animal parasite burdens. For example, by developing rational integrated control strategies based on improved diagnosis or farm management options or targeting treatment at infected animals using a Targeted Strategic Treatment approach.
In partnership with farmers, we will share outputs from the project, build an understanding of what farmers need to improve control of parasites in their animals without relying solely on traditional blanket treatment regimes, and assess the feasibility of implementing possible control options that emerge from the modelling framework.