Bridging knowledge gaps to combat Facial Eczema

The recent announcement(external link) of an $8.3 million commitment by the Ministry for Primary Industries through the Sustainable Food and Fibre Futures Fund, alongside a $9 million contribution from Beef + Lamb New Zealand and additional funding from other industry partners  –  totalling $20.75 million over a seven-year period – marks a pivotal moment in the fight against this disease.

This collective effort, encapsulated in the Eliminating Facial Eczema Impacts (EFEI) programme, promises to address the critical knowledge gaps and management challenges that have hampered progress for over a century.

FE, caused by the toxin-producing fungus Pseudopithomyces chartarum, leads to liver damage, reduced animal productivity, and severe animal welfare issues. Traditionally, management strategies have included the application of fungicides and zinc supplementation, methods that are not sustainable due to environmental and health concerns.

While selective breeding for resistance presents a promising avenue, it requires a long-term commitment to realise its potential as a viable solution. The economic toll of FE on the New Zealand agricultural sector is profound, with estimated impacts reaching $332 million annually due to reduced livestock growth rates and stock losses during severe outbreaks.

The knowledge gaps surrounding FE are profound and multifaceted. This is a critical barrier to the development of strategies to address the problem. Despite decades of concerted research efforts, our understanding of FE remains fragmented, particularly in areas critical for its control and eventual eradication.

The challenge of detecting the fungus Pseudopithomyces chartarum in pasture is one of these critical knowledge gaps in our fight against FE. The accurate measurement of spore counts in pasture, a crucial indicator of FE risk, is fraught with difficulties.
 
Current methodologies may not accurately reflect the true risk of FE to livestock because not all spores contain the toxin sporidesmin, which is responsible for the disease. This discrepancy means that even with high spore counts, the actual risk of toxicity could be over or underestimated, depending on the proportion of spores carrying sporidesmin.

This issue complicates the development of risk management strategies for farmers, who rely on spore counts as a key metric for deciding when to implement disease mitigation practices such as moving animals to safer pastures or beginning zinc treatment protocols. The variability in sporidesmin presence within spore populations necessitates a more nuanced approach to measuring FE risk, one that goes beyond simple spore counts to assess the actual toxic potential of pastures.

Understanding the factors that influence sporidesmin production by Pseudopithomyces chartarum, including environmental conditions, fungal genetics, and interactions with the host plant, is essential for developing more accurate predictors of FE risk.
 
Research into these areas could lead to the development of diagnostic tools that not only count spores but also measure the concentration of sporidesmin or identify spore variants more likely to produce the toxin. Such tools would represent a significant advancement in FE management, providing farmers with the information needed to make informed decisions about protecting their livestock from this debilitating disease.

The need for more effective diagnostic tools stands as a primary concern. Current approaches often fail to detect the disease in its early stages, particularly when animals are asymptomatic or presenting signs that are not easily recognised, leading to underestimations of prevalence and severity.