| A recent article by NADIS discussed Fly Strike and what the best ways are to reduce the risk in your flock.
The majority of sheep blowflies over winter as maggots in the soil. When the weather warms up sufficiently, they pupate and then eventually emerge as adult flies and, after feeding, start to lay eggs. Fly emergence starts first in warmer southern areas and then progressively moves to more northerly and upland areas. At present, the relatively cold spring means that in the majority of areas the maggots are only just turning into pupae, and, unless the weather warms up considerably in the next couple of weeks, the first emergence of most adult flies is not likely until at least towards the end of April or early May. However, it is possible that a small proportion of the blowfly population overwinter in sheltered spots, possibly in or around barns or sheds. In these cases, some emergence is possible even before the date forecast for the general fly population, so early vigilance is advised from April onwards.
Ways to reduce the risk of fly strike on your farm
Manage the fly population: Reducing the fly population early in the year has the greatest impact on the challenge to your clients’ flocks for the grazing season. Flies can lay up to 3000 eggs in a 3-month period so populations can increase quickly.
- Inexpensive fly traps have been shown to reduce strike incidence by 80% in a season
- Consider how muck heaps are sited and managed
- Encourage prompt disposal of deadstock
- Lameness – ensure levels of lameness are low and under control
- Reduce fleece contamination
- Minimise scour due to worms – Nematodirus infection is particularly important early in the season. Discuss roundworm control with your client as part of an integrated parasite control plan
- Dagging or crutching to remove soiled fleece from around the back end
- Apply preventative treatments in advance of the high-risk period
- Make sure you use the correct product and apply it according to datasheet advice
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