Horn flies, face flies, house flies and stable flies are pests that can have major economic and health impacts to livestock. Each has different lifecycles, attributes and vulnerabilities, making just one control almost destined to fail. Several approaches are required for effective fly control both in the barn and on pasture.
No matter the fly or health concern, it should be job one to keep cattle in good body condition. Healthy cattle plus fly controls equal reduced health and economic impacts.
Identify the Fly
Another important aspect of fly control is to identify the specific pests as their lifecycle, strengths and weaknesses will matter when choosing appropriate controls.
Horn flies - Breeding site: very fresh manure. Flies overwinter as pupae in or under dung pats.
Face flies - Breeding sites: Fresh droppings on pasture. Adult flies overwinter inside buildings.
Stable flies - Breeding sites: organic debris, feed areas, manure and urine soaked straw or wood chips.
House Fly - Breeding sites: debris, manure piles, animal bedding and spilt feed (hay, grain, silage).
Fly control in the barn
Mechanical Controls
- Good sanitation to prevent the breeding of flies is the key for management; keep areas clean and dry. Remove breeding sites like manure and bedding at least once per week or more frequently to break the life cycle of the fly.
- Check for water leaks; waterers should be checked daily to avoid excess moisture.
- Ventilate to ensure good air circulation which reduces manure moisture and discourages flies from laying eggs.
- Keeping the bedding dry should decrease the number of flies emerging.
- Avoid build-up of manure and mud along fence lines in exercise yards, or in gaps under feed bunks.
- Keep solid manure as dry as possible.
- Turn compost piles regularly to ensure heating which will kill eggs and maggots.
Physical Controls
- Physical Traps are effective for reducing adult fly numbers, especially inside buildings. These include sticky traps (roll, sheet or tape), light traps and baited traps (stinky traps) with various combinations like a glue board with a pheromone attractant.
- The most economical sticky traps are usually the "clothesline" type.
Tip 1: Straw bedding usually sustains more files than woodchips or sand.
Tip 2: Peppermint, basil, pine and lavender have shown acceptable repellence in laboratory tests.
Fly Control on Pasture
Flies on pasture are more problematic as it is difficult to avoid or remove breeding sites.
Helpful practices:
Encourage diversity in natural insect populations. Some insects can increase manure pie degradation decreasing both fly numbers and internal parasites.
A healthy soil may also increase manure degradation.
Rotational grazing systems may also help increase natural insect populations.
Use of chickens in pasture rotation immediately after cattle rotation. They will feed on maggots and pupae.
Drag pastures in hot dry weather to break up manure pats so eggs dry out and die.
Place walk-though traps in places cattle must pass e.g. between pasture and source of water.
Use baited traps near where cows congregate.
Other Controls:
Feed through controls – halts development of life cycle in manure (kills eggs).
Self-applicators of fly control products – cattle fly rubs and walk-through dust bags.
Ear-tags - Release insecticide slowly over time, effective from mid-June to July. Rotate insecticide types each year to prevent resistance.
Pour-on and sprays provide short-term control, requiring reapplication every 2-3 weeks throughout the flying season. Not effective before pasture turnout.
Tip 3: Put up nestboxes to increase numbers of insect eating birds such as swallows.
Sources: OACC - Dalhousie University and Beef Cattle Research Council
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