Fly Control in Pastured Cattle

Because cattle produce so much manure fly populations can be hard to manage and control even when cattle are kept in open pasture and not confined.

Heifer Walking Down A Lane

Flora Walking Down The Grassy Lane

Here in western Pennsylvania summertime means fly season for folks who raise cattle. Heavy fly infestations in cattle can be a real animal welfare headache. That’s because flies bite, suck blood; spread disease and cause agitation and a general misery both in cattle and humans alike.

In this part of the US, there are two major types of flies that trouble cattle: face flies and horn flies. If you are new to keeping a family cow or plan on keeping cattle in the future it is a good idea to learn the difference.

Face flies look at lot like big house flies. They tend to cover large areas of the face and like to feed on the eye, nose and mouth secretions that cattle produce.

Heifer With Face Flies

Josie With Summer Face Flies

Face flies transmit the bacteria Moraxella bovis, which is the primary cause of bovine pinkeye. Pinkeye is an extremely contagious inflammation of the cornea and conjunctiva of cattle and can result in blindness if not treated promptly.

Horn flies are about half the size of house flies and have pointier looking wings.
And like the name suggests they prefer to gather in a large mass around the horns or poll of cattle. But horn flies don’t just stop with the head. They are blood suckers and congregate wherever they can’t easily be rubbed or brushed off.

Horn Flies

Horn Flies On Cattle

Horn flies like to stay on cattle continuously and will often face directly downward towards the ground while they cling to cattle. The back and shoulders of calves and full grown cows are all easy targets for horn flies. During rainy weather they will move to the belly and throat of cattle for shelter from the rain.


There are a few different types of products and delivery systems that aid in the control of flies on cattle. The type of fly control that a producer or small holder will choose depends upon budget, herd size, management system and personal preference.


A daily insecticide spray on is a fairy effective control measure if you have only a few cows and if you handle them every day. It’s the type of fly control that we use and it will give about a half to a full day’s protection.


A pour on fly repellant is a good choice for both dairy and beef cattle and can last up to 4 weeks. I keep bugging my husband to get some so we can quit with the daily spray.


Dust bags and oil rubs are very convenient and can be located between two fence posts or a gate where cattle will have to walk every day. Dust bags are filled with powdered insecticide that gets applied like bath powder on bovine heads, backs and necks when they walk underneath it.
Oil rubs are extremely effective and look and act a lot like the big horizontal wiper mops that you see in automatic car washes. Instead of a car passing through and being dosed with soap and water, and cow passes through and gets dosed with insecticide.


Insecticide ear tags are an effective but expensive form of fly control. Best results are obtained if tags are set in both ears and not too soon in fly season. Both caution and rubber gloves must be used when applying insecticide ear tags and flies can develop a resistance after a couple of years of use.


The way a feed or mineral additive works is that insecticide in the feed or mineral block is eaten by the cattle and then passed through the digestive tract and into the manure.
The insecticide reduces the number of flies emerging from the manure and helps to keep fly populations under control.

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