Flies on the farm are not just pesky. They can impact production, spread disease and take a toll on overall animal health. That is why Penn State Extension Specialist Robert Graves says that fly control is a critical point of providing dairy cow comfort.
According to Graves, cows provide flies with “good living.” For biting flies, the cow is an immediate food source. For others that look for manure patties to lay their eggs, cows provide the necessary environment.
“We want to figure out how to keep flies uncomfortable and cows not a good place for them to live,” he points out. To flourish, flies need a few simple conditions: food, water (moisture) and the right temperature. This recipe is the same one that odor-causing microbes desire. Manure, urine and spoiled feed piles can provide a balance of those three things that both flies and microbes relish.
In order to reduce flies, those ideal environmental conditions need to be interrupted. One of the most simple ways to do that is by removing the food sources and breeding sites. Graves explains that keeping farms clean makes conditions uncomfortable for flies. While simple in concept, this does require thought and effort. It may seem obvious and easy to keep highly visible areas like walk ways, alleys and lots scraped clean of manure; however, if there are areas out of reach from the skid steer bucket, like underneath and behind waterers or feeders, manure may accumulate. These are areas that cows do not have access to and are often overlooked because they are not places where cows lay, nor do they pose a risk to directly getting the cow dirty. However, out of sight should not be out of mind because these areas can host thousands of fly larvae, taking as little as 10 days to reach the adult fly stage of their life cycle.
He suggests to keep this in mind as a cow comfort consideration, even when designing barns and buildings. Posts or indentations that protrude or recess into the edge of a concrete surface create nooks and crannies too small to keep clean with the skid steer alone. Make cleaning convenient and possible, he says, so there are no piles of manure that get pushed in places and provide the environment for things we don’t want.
There is no magic tool to make flies go away, but Graves says one of the most effective tools is a manure scraper that can be manually used to clean out corners where skid steer scraping fails to reach. A load of gravel may also provide the necessary fill for holes in the barnyard where water sits and becomes stagnant, another ideal fly and odor scenario.
While flies may be attracted to the environment that cows provide, the calf environment can be even more inviting. “Is that nice dry bedding on top icing on the fly breeding factory below?” asks Graves. In the summer, calf hutches with their usual mixture of straw, moisture and delayed cleaning often make an ideal environment for generating huge populations of flies, says David Wolfgang, Penn State University Extension veterinarian. Regular cleaning, along with using sawdust or shavings for bedding, can help reduce the fly population.
Another ideal place for flies to lay their eggs is in and around manure holding areas. Bedding material and manure should be removed often and stacked, composted, covered with black plastic or spread thinly so that it can dry out. This disturbs the ideal conditions for flies by removing the moisture that they need in their environment. Wolfgang also recommends agitating pits and removing any solid material floating or adhering to the sides of lagoons or other manure storage facilities in order to remove the sites where flies would hatch. Further, trimming weeds and brush around manure storage, buildings and fencerows will keep fly populations under control, along with disposing of garbage and carcasses that provide the decaying matter for larvae to feed on.
Regular removal and spreading of manure and decaying organic material is an effective step in controlling flies, and Graves cautions farmers to not “deliver a fly explosion to your neighbors with your manure spreader.” This can be particularly important in keeping good relations with both farm and non-farm neighbors. When hauling out manure and bedding, there may not appear to be a fly issue. However, that material could be filled with fly eggs and larvae that will soon hatch, “erupting with flies.” “It may look like manure attracted them there, but in all likelihood, we took them out,” Graves says, explaining that this is part of understanding the life cycle of flies and where the problems originate from.
Controlling flies by means of keeping the farm and facilities clean is a season-long task. “Do your spring cleaning continuously, and keep doing that until fall frost,” Graves recommends.