Why Flies love Dairy Farms: Risks and Strategies

Did you know that the lifecycle of a fly is dependent on temperature, and farms offer the ideal 5* accommodation for breeding flies? With the ambient conditions, mountains of muck and the intensification of farming throughout the UK leading to the rise in problem fly infestations. Reproducing year-round in warm conditions, their life cycle becomes shorter as temperatures increase. Up to fifteen generations of flies can be produced in just one season, so it is important to act quickly for effective fly control. 

Why control flies on dairy farms? 

Flies are a human and animal health hazard, carriers and transmitters of diseases, including salmonellosis, avian influenza, coccidiosis, foot and mouth and mastitis. Some of which are zoonotic (transferable to humans). Flies are commonly linked with human infections such as stomach bugs, blood poisoning and pneumonia.  

Flies cause huge financial losses to the agricultural industry. Every year farmers up and down the country are out of pocket with flies accounting for billions of pounds worth of losses on a global scale. An insect nuisance recognised under the Clean Neighbourhoods & Environment Act 2005, giving local authorities the power to inspect premises and issue abatement notices for non-compliance.  

Flies cause discomfort and stress to animals. When flies prevent livestock from being able to settle and feed, it’s no surprise that overall productivity and profitability will also decrease. A fly infestation will dramatically reduce food intake, leading to reduced production i.e. daily live weight gain and milk yield.  

The impact of flies to Dairy farmers & in calf rearing… 

Fly control is particularly important on dairy farms and in calf rearing settings, where farmers can’t afford to take any risks. Flies can spread the bacteria which causes Summer Mastitis, costing up to £300 per case to treat. In calf-rearing systems, infestations of biting flies reduce weight gain by 20%. Studies show that when flies affect cattle, they suffer a growth reduction of approximately 0.3kg per day and cows can suffer a daily loss in milk production of up to 0.5L. These reductions will undoubtedly affect farmers ability to bring in the same profit as when the flies are kept at bay.   

Even in the most technically advanced facilities, fly infestations can pose major problems, farmers notably struggle during the peak summer months where increased temperatures aid fly populations to flourish. Straw bedding that is left untouched for 4-6 weeks or more in calf rearing areas are prime places for fly breeding to occur. Flies will breed in calf igloos, which also need to be treated with suitable insecticides. 

Farms are a fly’s B&B, muck is their accommodation and animals provide their food. In most dairy farms, muck will be removed or scraped from sheds into a slurry pit. In other instances straw bedding will be relocated to external heaps. Larvae live in the top 4 inches of muck, they spend the first 3 stages of their lifecycle in the warmth of a group below the surface of the muck, they then make their way to the surface to seek a dry place to pupate, before emerging as an adult fly. When considering fly control all areas should be treated, flies are clever and will avoid laying in treated muck if there is an alternative untreated area readily available. Flies can also be found in cow feed, also known as spilt cake, which is given when they are being milked. 

Different types of flies… 

Each fly species has its own breeding and feeding habits. Knowing, monitoring and identifying the species will determine the best treatment strategy. Treating a biting fly infestation is different to non-biting flies, so let’s take a look at the differences… 

Non-Biting Flies (e.g Common house Fly/ Lesser house Fly) while it’s true they cannot actually bite animals they still transmit disease from unit to unit or farm to farm. The reproduction and feeding habits of the flies, combined with the structure of their mouths and feet, mean that they are able to act as mechanical vectors for many pathogens; spreading viruses, worms and bacteria. Non-biting flies are prevalent around the eyes of cows in search of mucus. 

Biting Flies (e.g Sable Fly) like to be near their host for a blood feed and are attracted to Co2, warmth and food sources to breed. They can cause anaemia, loss of condition and weight loss in farm animals simply by distracting them from eating or grazing. Animals can also develop a hypersensitivity to the saliva of a biting fly, which can result in painful skin conditions. Biting flies are the common enemy for dairy farms, farmers can get kicked because of stressed animals and cows have been known to kick off the milking cups due to fly aggravation. 

Intensive farm fly control… 

In the past Dairy farmers have relied upon traditional pour on products for cattle to control fly infestations, these have proven to be an inadequate form of fly control during the hotter summer months. Forcing farmers to seek alternative methods and integrated approaches of best practice to controlling flies. Implementing a successfully, proactive strategy and course of treatments will provide both stress free fly control and peace of mind. Lodi UK provides a one-stop-shop of intensive fly solutions to control every stage of a fly’s life cycle, we offer first-class technical support, as well as our recommended approach to successful on farm fly control which is outlined below: 

Monitoring fly activity is essential to identify the species causing the infestation, ensuring that the most appropriate active is used in the most appropriate location. In some cases, Environmental Health Officers (EHO’s) may require evidence of monitoring. Keeping a record of numbers and locations will help build a history for future reference. A Digrain Fly Glue Roll can be labelled with the date, cling wrapped and kept as evidence. Using a fly reel kit, roll or fly trap to monitor fly activity will help to spot an infestation as it starts to peak. 

Larvicides manage fly larvae (80% of life cycle) in breeding areas such as manure heaps, slurry pits, straw bedding areas. If fly numbers in animal housing are increasing, farmer favourites such as Larvenol and Maggots are essential to interrupt the fly life cycle growth and development stages. 

Adulticides kill adult flies (20% of life cycle) Eliminate migrating flies and those already present using baits, sprays, wettable powders and fogging liquids. Knockdown Adulticides (Dairy Fly Spray, Phobi F&F+, Digrain Control) kill flies on contact. Residual Adulticides (Twenty One, Sheila, Perbio Choc RTU) leave surface residues for longer term control.  

Responsible product use & education… 

Alternating between insecticide treatments every few months where possible, prevents flies using natural defences to overcome active ingredients and reduces resistance. Each active ingredient and formulation has specific instructions regarding suitable usage areas, spaces and surfaces.​ Always read the label & follow product instructions closely to ensure effective and safe product application. You can find out more information in our ‘Guide to controlling insects on farms’ and remember to always seek professional help from a pest controller. 

Flies equal money - Ultimately, effective fly control will save farmers precious time and pounds, resulting in increased production, increased conditioning of animals whilst assisting in reducing the transmission of disease. So, ask yourself is a fly infestation really worth the risk?