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Working with the weather to manage parasites of livestock in changing climates

Parasites can be found in every environment on earth and infect a wide range of hosts – birds, fish, plants, insects, wild animals, domesticated animals and humans.  When parasites are discussed they often trigger an “ewww” reaction.  However, they have much more serious economic, food security and animal health and welfare impacts when they infect grazing livestock.  Grazing livestock contribute greatly to food security and this is not going to change any time soon.  Not only is the global population (and therefore food requirement) growing, there is an increasing demand for animal-based food products in developing regions and there is an essential role of animal products in marginal environments where crop production is infeasible.  Parasite control is therefore vital, but is not easy to achieve.

Many parasites have complex lifecycles which depend upon specific climatic conditions.  For instance, temperature and moisture determine development rates and survival.  Farmers could once use this to their advantage as the predictable, seasonal weather patterns led to predictable, seasonal patterns of parasites.  Reliable livestock husbandry practices therefore developed for parasite management.  However, in recent years there have been changes in climate and less predictable weather patterns.  Traditional management practices are often no longer effective as parasites are being found in unexpected regions and at unexpected times of year.  What’s more, whilst other organisms are being put under threat by climate change, parasites are successfully evolving and adapting to these changes in environment due to their short reproductive cycles.

Predicting the risk of infection to parasites involves multiple areas of expertise.  An in-depth knowledge of parasite characteristics is essential, and needs to be updated as they evolve.  Accurate forecasts for climate are also needed to help predict which regions may have an environment suitable for the parasite and changes to its seasonality.  An accurate forecast for weather (daily climatic conditions) is essential for certain parasites.  Combining historical data with forecasts, knowledge of the parasite’s requirements for development and farm characteristics (such as altitude and orientation) within complex models gives precise information on infection risk and helps farmers to be one step ahead of the parasites.  Technology is also aiding the rapid diagnosis of specific parasite infections to guide effective management practices.
Despite these advancements in parasite control, uptake of the technologies by farmers is often slow. The science behind parasites and the models developed are complicated and daunting.  Livestock farming is demanding, both economically and in terms of labour.  Therefore farmers need these complex technologies to be transformed into tools that are still effective, yet simple and easy to integrate into their current practices.  They need to feel confident in using the tools and understand the benefits that come with them – not the science.  These benefits include more efficient animals, both economically and environmentally, and improved animal health and welfare.

There is still much to learn about parasites. The rapid changes to the environment, the livestock industry and the parasites themselves means that this is an area of work that will be ongoing for the foreseeable future.  There is a huge need for collaboration between disciplines to not only develop the tools, but also to communicate their need and promote their use on farms.  This barrier to technology uptake could be a bigger hurdle for scientists than technology development itself.

This blog is written by Cabot Institute member Olivia Godber, a PhD student in the School of Biological Sciences at the University of Bristol.

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