The next 20 years will be transformational for Australian agriculture: Here’s what you can expect

Recommendations for stud staff:
Understanding the risk
Mares are most at risk of exposure to caterpillars from March to June. During this time, caterpillars are on the move, and mares can encounter them in several ways:
Horses can accidentally ingest microscopic, barbed caterpillar setae while grazing or feeding. These setae migrate through the gastrointestinal tract, carrying bacteria, and invade deeper tissues, including the uterus in pregnant mares. This can lead to severe infection, resulting in fetal death and abortion.
Caterpillar lifecycle
The moths that produce these caterpillars emerge from the ground in late spring (October to November). They mate, lay eggs in masses on native trees, and die. Caterpillars hatch from the eggs, feed on tree leaves at night, and return to the nest during the day. As they grow, the nest expands. When caterpillars eat all the foliage on a tree, they move in head-to-tail processions to another tree to build a new nest. By May to June, the caterpillars are mature and move into adjacent pasture to pupate, lying dormant until they hatch as moths in October to November.
Locate and eliminate
Removing pregnant mares from paddocks with caterpillar nests reduces the risk of EAFL, but this is often impractical due to the widespread distribution of nests. Finding and removing the nests is a more practical option. There are three nest types:
Handle nest material with care
It is important to implement protocols for the safe handling of nest material and managing human exposure. Always wear personal protective equipment (PPE) when handling egg masses and nests, including disposable coveralls, gloves, eye protection, mask, and head cover.
Caterpillar nest material can cause severe itching and allergic reactions if it touches the skin. It can also cause severe irritation if it gets into the eyes, nose, or mouth. Individuals with asthma should be extra cautious. Nest material is light and easily dispersed by wind, so only remove nests during calm weather.
For disposal, deep burial is better than burning, as nest material can be dispersed by burning.
Prevention and early detection
While prevention is the ultimate goal, pregnancies can be protected if the condition is identified early and treated appropriately. Take these steps to protect your mares:
By staying vigilant and taking proactive measures, we can protect our mares and help prevent EAFL.
Find out more about caterpillar control to reduce EAFL risk
Learn more about AgriFutures research investments in equine diseases and parasites
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