Improve Dairy Productivity by Implementing Fly Control Measures
Mar 10, 2021

Tara Jo Bina
Countryside Feed Livestock Nutrition
We all know how a few biting flies can put the damper on a family picnic. Just imagine multiplying the pain of a fly bite by a few hundred, and you’ll begin to get a sense of what your herd has to deal with. The impacts of flies extend far past this discomfort; it is estimated that flies cause the United States dairy industry to suffer $360 million in lost production every year!
Several types of flies use cattle as a host, the most common being, horn flies, stable flies, house flies, and face flies. Cows battle painful bites of horn flies and stable flies all day long. The parlor is an easy place to see the discomfort flies cause, but they also deal with biting flies in the feeding area as well as while they are trying to rest. Without fly management, this irritation alone can cause up to 15 – 30% decreases in milk production! Face flies and house flies may not cause irritation from biting, but they are major vectors of many diseases including pink eye and mastitis.
Fortunately, feed-through larvicides and garlic products are available to help limit the impact of all types of flies on our animals. This is important, because even though we’ll never completely eliminate flies, the more comfortable a herd is, the more profitable it will be. The economic threshold for implementing fly control measures on the typical dairy is only 50 flies per cow.
Feed Through Larvicides
We carry two high quality feed through larvicides at Countryside Feed: ClariFly® Larvicide and Altosid® IGR. These products limit the number of flies by killing them in the larval and pupal stages. Reduced fly numbers are generally observed about 3 weeks after being introduced to cattle.
To help determine ideal timing, we recommend producers begin feedingClariFly® or Altosid® IGR approximately 30 days before the average date that daily daytime temperatures typically reach 65° F. This is the point when overwintering flies emerge to mark the start of the fly season. This process should be maintained into the fall season until 30 days after first frost has been recorded.
Typically, Altosid® IGR is mixed in minerals for grazing cattle, whereas ClariFly® is commonly used on cattle in confinement. Countryside Feed has the ability to include either feed through larvicide in different feed formulas!
Garlic Products
We also carry quality garlic products at Countryside Feed that may assist in decreasing fly pressure. Although these products don’t kill flies, they can act as a repellent to help prevent the pests from biting. In addition to this benefit, studies have indicated that garlic helps improve the immune system, offers antibiotic properties and supports an overall increase in production. If you decide to use a garlic product in your operation, we recommend feeding it for the same time periods as feed through larvicides, 30 days before flies emerge through 30 days after the first frost.
Groups to Implement Fly Control Strategies
The more cattle that receive a larvicide, the more effective fly control you have over your entire operation! Be sure not to overlook your dry cows and heifers! These groups of cattle can be easy to put “out of sight, out of mind”, but they are important groups to also include fly control. Flies are a major vector of mastitis causing bacteria from cow to cow (or heifer). Dr Stephen Nickerson (University of Georgia College of Agricultural and Environmental Sciences) reports up to 50% of blind quarters in first lactation heifers can be attributed to bacterial spread by flies.
If you have questions about selecting the right fly control measures for your dairy, please call your local Countryside Feed nutritionist. Some products might be a better than others depending on your operation, so we’re always here to help you make educated selections for your herd.
Countryside Feed Livestock Nutrition
We all know how a few biting flies can put the damper on a family picnic. Just imagine multiplying the pain of a fly bite by a few hundred, and you’ll begin to get a sense of what your herd has to deal with. The impacts of flies extend far past this discomfort; it is estimated that flies cause the United States dairy industry to suffer $360 million in lost production every year!
Several types of flies use cattle as a host, the most common being, horn flies, stable flies, house flies, and face flies. Cows battle painful bites of horn flies and stable flies all day long. The parlor is an easy place to see the discomfort flies cause, but they also deal with biting flies in the feeding area as well as while they are trying to rest. Without fly management, this irritation alone can cause up to 15 – 30% decreases in milk production! Face flies and house flies may not cause irritation from biting, but they are major vectors of many diseases including pink eye and mastitis.
Fortunately, feed-through larvicides and garlic products are available to help limit the impact of all types of flies on our animals. This is important, because even though we’ll never completely eliminate flies, the more comfortable a herd is, the more profitable it will be. The economic threshold for implementing fly control measures on the typical dairy is only 50 flies per cow.
Feed Through Larvicides
We carry two high quality feed through larvicides at Countryside Feed: ClariFly® Larvicide and Altosid® IGR. These products limit the number of flies by killing them in the larval and pupal stages. Reduced fly numbers are generally observed about 3 weeks after being introduced to cattle.
To help determine ideal timing, we recommend producers begin feedingClariFly® or Altosid® IGR approximately 30 days before the average date that daily daytime temperatures typically reach 65° F. This is the point when overwintering flies emerge to mark the start of the fly season. This process should be maintained into the fall season until 30 days after first frost has been recorded.
Typically, Altosid® IGR is mixed in minerals for grazing cattle, whereas ClariFly® is commonly used on cattle in confinement. Countryside Feed has the ability to include either feed through larvicide in different feed formulas!
Garlic Products
We also carry quality garlic products at Countryside Feed that may assist in decreasing fly pressure. Although these products don’t kill flies, they can act as a repellent to help prevent the pests from biting. In addition to this benefit, studies have indicated that garlic helps improve the immune system, offers antibiotic properties and supports an overall increase in production. If you decide to use a garlic product in your operation, we recommend feeding it for the same time periods as feed through larvicides, 30 days before flies emerge through 30 days after the first frost.
Groups to Implement Fly Control Strategies
The more cattle that receive a larvicide, the more effective fly control you have over your entire operation! Be sure not to overlook your dry cows and heifers! These groups of cattle can be easy to put “out of sight, out of mind”, but they are important groups to also include fly control. Flies are a major vector of mastitis causing bacteria from cow to cow (or heifer). Dr Stephen Nickerson (University of Georgia College of Agricultural and Environmental Sciences) reports up to 50% of blind quarters in first lactation heifers can be attributed to bacterial spread by flies.
If you have questions about selecting the right fly control measures for your dairy, please call your local Countryside Feed nutritionist. Some products might be a better than others depending on your operation, so we’re always here to help you make educated selections for your herd.