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How To Control Flies on a Dairy Farm

Rowan Burgess |

Fly control on a dairy farm requires a management programme that reflects the number of cows and the farm design. 

Simply put: flies stress cows, affecting their feed consumption and resulting milk output. (They probably stress you out, too!) Flies also spread disease amongst the herd and other species - including humans.

Additionally, fly control protects animal welfare and farm productivity. It is essential to a healthy living space and working environment. There are several ways to approach fly prevention and infestation; in this article, we’ll outline a range of systems and fantastic products to give you peace of mind.

Why Is Fly Control Important on Dairy Farms?

Flies proliferate on dairy farms because they offer the perfect storm of manure and warm temperatures - ideal for the many lifecycles of fly species.

As winters become warmer in the UK and summers feel hotter, fly problems are only going to increase.

Poor fly control affects herd health, causing discomfort to your cows and loss of condition. Additionally, as we mentioned above, certain diseases can spread far and wide - even to humans.

Fly infestations also impact the all-important milk yield, as stressed cows eat less. Indeed, production can drop by as much as 25%! Unregulated fly populations on a dairy farm will inevitably compromise animal welfare and affect productivity.

But there’s more. Poor fly control can also breed more physical complaints from neighbours in your farm’s vicinity, impacting environmental licences. Environmental health affects the whole community; this is a potent reason to improve fly management and pest control.

Which Flies Should You Look Out for on a Dairy Farm?

1. House Flies

House flies may not bite but they’re still connected to the transmission of many disease organisms. Indeed, it has only been in recent times that scientists have realised just how efficient these seemingly ordinary flies are at acting as bacterial shuttles. More disease for you and your cows!

2. Horn Fly

Horn flies are one of a dairy farm’s most economically damaging insects, responsible for weight loss, lower feed efficiency, and decreased milk yields. 

Not exactly large, horn flies are half the size of house and stable flies - but they pack a punch. These suckers lay eggs in fresh cowpats and tend to congregate on the backs of cattle, where they go in for a second round of dinner.

3. Stable Flies

Sometimes called horse flies, stable flies have an excruciating bite and could cause intense irritation if found in a body area your cow can’t reach. These little pests bite and latch on, feeding mainly on the legs and flanks of a cow.

4. Face Fly

These flies congregate around the eyes of the cow, where they’re attracted to moisture. They sound innocuous, but face flies spread diseases from one eye to the other - from animal to animal. They also cause damage to the delicate tissues around the eye. Not something to be messed with! Luckily, we have a few solutions.

Fly Control Solutions for Dairy Farms

Dairy Fly Spray

Dairy Fly Spray strikes against all flying and crawling insects. You won’t need to worry about different products for different species; this one does it all.

This concentrated liquid has a fast knock-down rate for use in and around farm buildings - including milking parlours, stock housing, and rearing sheds.

Easy to dilute, mix 50ml with 5 litres of water and spray directly at the insects. 


  • For use on buildings and directly on flies and insects
  • Economical concentrated spray


  • Active insect control only, no residual

Who’s This For?

Any size of dairy farm and mixed species units

    Red Top Fly Trap

    Red Top Fly Trap works whilst you’re busy doing other things. Add water and suspend the trap 2-2.5m above ground level, adjacent to the congregation area.

    Direct sunlight activates the pheromone in the trap, producing a consistent and long-lasting solution.

    Red Top is a biodegradable bait and has proven success worldwide; it’s a labour-saving fly control method that doesn’t require a power source or active spraying.


    • Pheromones attract female flies, reducing a breeding population
    • Passive system with no power or time required
    • Biodegradable at point of disposal


    • Only works in direct sunlight

    Who’s This For?

    Dairy farms and other types of animal housing, including mixed livestock enterprises and stable yards

      Digrain Insect Killer Spray

      Diagrain Insect Killer Spray contains fast-acting Tetramethrin combined with Permethrin, assuring a long-lasting residual. 

      Digrain covers a wide gamut of crawling and flying insects, while the cans are large enough to make an impact on several farm sites. However, this product does require a licensed application.


      • Dual action rapid knock-down rate with long-lasting residual
      • Deals with flying and crawling insects
      • Large 600ml Can


      • N/A

      Who’s This For?

      Dairy farms with severe fly concentrations in defined locations

        Digrain Bugster EC Insecticide

        This insecticide from Digrain contains prallerthrin, which works in minutes. We appreciate that Bugster has some long-lasting residual benefits - an 8–12-week residual action! Digrain Bugster also kills wasps, red mite, fleas and cockroaches. That’s multiple species for the price of one.

        This potent product can be sprayed on surfaces and used for hot and cold fogging, making it ideal as a rapid-target tool in a hygiene management programme. While Bugster is more labour-intensive, it gets the job done.


        • For fogging and as a surface spray
        • Blends fast knock-down results with a long-lasting residual
        • Tackles multiple species


        • Dilution and preparation required
        • Labour-intensive

        Who’s This For?

        Dairy farmers who want to implement a preventative hygiene programme and for livestock keepers with an immediate infestation or outbreak

          Vulcan P Rfu Fly Spray

          Ready for immediate use, the chemical formulation in Vulcan P Rfu Fly Spray offers instant results, working on more than one front.  

          In addition, this long-lasting residual spray contains piperonyl butoxide (PBO), which braces for any resistance or tolerance issues. PBO works within Vulcan P Rfu to increase its effectiveness, stopping insect enzymes and giving the spray time to do its job. Simply put, it’s the perfect ally.

          Vulcan is odourless and multi-use with either an atomiser or a compression sprayer, providing both short and long-term solutions to fly control.


          • Contains the synergist PBO to enhance performance
          • No preparation required
          • Odour-free


          • Only treats midges and flies

          Who’s This For?

          Dairy farmers or other animal keepers who want an instant fly control product with the benefit of a long residual action

            Fly Glue Roll

            A traditional idea upgraded for modern agriculture, this fly glue roll features a 3D pattern and fluorescent colour - highly attractive to farm flies! Its surface boasts a unique glue formula impregnated with fly sex pheromones. Non-toxic and biodegradable, Fly Glue Roll works 24/7 - and it works passively so you don’t have to!

            Keep this trap in a warm location with poor ventilation - or anywhere flies congregate.


            • Suitable for any location and season
            • Environmentally friendly and biodegradable
            • Unique patented design


            • Infestations may take time to clear 

            Who’s This For?

            Dairy farmers who want to avoid the use of chemicals

              Pluszap Electric Fly Killer

              This electric fly killer works instantly as a quick alternative to labour-intensive spraying and chemical products. It’s ideal for dairy farms of all sizes as part of a fly control programme. 

              Designed for optimal efficiency, the offset triangular killing grid creates a larger catch area that’s easy to clean and remove. 

              While numerous mounting options suit all types of animal buildings and locations, the Pluszap Electric Fly Killer complies with RoHS guidelines.


              • Chemical and labour free
              • 24/7 fly control
              • Instant and long-term fly management


              • Power costs

              Who’s This For?

              Milking parlours and animal housing on dairy farms

                How To Control Flies in a Calf-Rearing Area

                Good fly control management is essential across the farm to protect calves, not just in the calf-rearing area.

                Regular hygiene programmes, clean bedding, and good ventilation help manage the calf unit's fly population. Be sure to clear out and wash the units down at regular intervals, especially prior to applying sprays. While moving vulnerable calves can feel tedious, this step ensures greater herd health both now and down the road.

                Fly control is essential across a farm, as flies travel long distances to bother your cows. Think holistically and focus on the greater whole for ideal insect management.

                Can You Put Fly Spray on Calves?

                It’s a good rule of thumb to check with your vet before applying sprays. Flies can overwhelm newborns and cause serious health issues, especially with the amount of bodily fluid after birth.

                Starting each calf off on fresh bedding helps delay the ingress of flies on manure. Keeping the calf area as clean as possible daily helps with fly control.

                Frequently Asked Questions

                Are Fly Control Products Safe for Calves?

                Always check the manufacturer’s guidelines for time-delay instructions before introducing calves to the mix. Additionally, your vet can advise on the safety of products for cows and calves of varying ages. Non-chemical products - like electric fly killers - are a safe bet for effective treatment, as well as topical fly treatments.

                Final Thoughts

                Fly control is vital on a dairy farm to protect herd health, promote animal welfare, and optimise milk yields.

                Dalton’s fly control products offer a range of options for fly control, including chemical and non-chemical-based choices to suit different farm designs and herd sizes. We offer value for money plus years of expertise in the dairy sector, sourcing the most effective and innovative products for optimal fly control and management. But more than any of these, we care about your farm safety and peace of mind. Check out our website and order without delay.