Did You Know… Cattle Fly Control

— Written By and last updated by Pam Brylowe

            Welcome to summertime! With summer comes warmer weather, greener pastures, and…flies! Have you thought about how to protect your cattle against flies? In this article, you will learn more about several common species of flies, the diseases they cause, and how to protect your cattle against them.

            The first fly we will discuss is the face fly. It can cause your animals to drop weight and milk production, as well as serve as a vector for pink eye. Adult face flies are active from early spring to late fall. Female adult face flies will feed on nasal and eye secretions during the day and rest on vegetation at night. They lay their eggs on fresh cattle dung; larvae develop about five days later. To pupate, they crawl out to the soil and about a week later, emerge as adults. Control of the face fly is very important because of its ability to cause blindness from pink eye.

            The horn fly can cause many problems including bunching, and reduced feeding and weight. This could cause you to lose money as a producer. Male and female adults feed on cattle blood and stay on the animal almost 100% of the time. They feed about 24 – 38 times per day. Their eggs are laid on dung and this is also where the larvae develop. Underneath the dung, pupae form and emerge about 6 – 8 days later during the summer. Their peak is in late summer. Controlling horn flies is very important because they can cause a major reduction in milk production.

            The third fly we will discuss is the stable fly. Like the horn fly, it is a biting pest and can also cause bunching, and reduced feeding and weight. It will also cost you money per animal as a producer. Adults stable flies bite at the cow’s legs, back, belly and sides and take one bloodmeal per day. They are only in contact with the cow for about 2 – 5 minutes per day. Their eggs and larvae are found in decomposing or wet straw around hay bales. Cattle will typically kick and stamp their legs to try to rid of these pests. Their effects are worse during hot weather.

            Control of these types of flies, as well as other types is very important. Various methods of fly control include feed-through supplements, tagging applications, and fuel-based applications. There are currently products on the market that are feed-through insect growth regulators (IGR). These are available in many different mineral supplements. Also, there are the tried and true “fly tags” that have been commonly used for years. However, just like with dewormers, a rotational method of different fly tags (the active ingredient being what you want to rotate) is best to help from breeding resistance in fly populations. Finally, there are fuel-based products that can be sprayed or put into a backrub for cattle. These are very effective, but sometimes can wash off in heavy rains and need reapplication.

            Proper management of your farm’s fly population is key. If your cattle are using their energy bunching up and stamping their legs, they are not grazing. This, in turn, means they are having a lower feed efficiency, meaning you could be losing money. By managing your fly population, you are giving your cows the time and energy they need to be successful on your farm.

            North Carolina State University and North Carolina A&T State University commit themselves to positive action to secure equal opportunity regardless of race, color, creed, national origin, religion, sex, age, veteran status, or disability. In addition, the two Universities welcome all persons without regard to sexual orientation. North Carolina State University, North Carolina A&T State University, U.S. Department of Agriculture, and local governments cooperating.

            This article was adapted by Margaret A. Bell, Livestock Agent – Craven & Jones counties, from “A Thousand Points of Flies” by Holly Ferguson, Ph.D Washington State University. It is scheduled to be published in the Jones Post weekly newspaper on June 6, 2013.