Planning ahead for facial eczema season
Last year was a horrific season for facial eczema (FE) with numerous clinically and sub-clinically affected animals seen during the season and, even now, we are still seeing its effects coming through.
Fortunately FE is a relatively predictable disease with risk increasing as certain conditions prevail. The fungus responsible for producing the toxin that causes FE associated liver damage thrives in dead leaf matter and a combination of warmth (night time temperatures above 12°C), moisture and humidity will lead to an exponential rise in the number of spores and consequentially pose a high risk to animal health.
There are a number of viable approaches to managing FE but some key points are:
- Begin prevention strategy based on environmental conditions.
- Start monitoring your paddocks, via spore counting, sooner rather than later (we recommend from mid January onwards) and/or keep an eye on local trends (see our weekly report here...). However there can be enormous variation between, and even within, paddocks on the same farm. Start prevention strategies once counts start to creep up around 10-15,000 spores per gram.
- Fungicide spraying of paddocks costs around $10 to $15 per hectare. Be aware that it's no good once spore counts are already high, it may need repeated application(s) and it is important to continue to monitor treated areas.
- Consider putting in alternative forage species, such as chicory or plantain, to feed during high risk periods as many crops do not create an environment that allows growth of the fungus.
- Zinc (Zn) supplementation is the main preventative strategy for FE control and there are many different supplementation methods each with its own pro's and cons. Oral drenching, water treatment at whole farm level, water treatment at trough level (Peta dispenser), in feed, on pasture and the application of slow release boluses.
- In more extensive systems, heifer grazing blocks, or in areas where there are different sources of water for animals to drink from, the most reliable form of supplementation is usually a slow release Zn bolus. This is especially true in the case of sheep. These deliver a guaranteed daily dose of Zn and have a defined pay out period, however their application can be repeated in a prolonged FE season.
- Given that the effect of exposure to the fungal toxin is cumulative year on year be aware that groups of animals hit hard with FE last year will benefit from aggressive prevention this year, such as last years hoggets that have been kept as two-tooths.
- Whatever strategy you plan to use this season it is important that you continue to check it is working - do a spore count a defined period after fungicide spraying and/or utilise blood testing to check for liver damage.
Knowing the risk factors for FE, having a strategy in place for monitoring the challenge and for preventing it's effects is well worth while. For further information, or if you would like a hand planning your approach to FE this season, don't hesitate to give your vet a call.