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Different Cattle Pests Require Different Methods Of Control

published: July 27th 2009
by: David Burton
source: News-Leader

During a year's time, beef cattle are exposed to a variety of insect pests that may impact their performance and the pocketbook of the beef producer.
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Examples of costly parasites include the common horn fly (which shows up in huge numbers in mid to late summer if not treated against), face flies, ticks, cattle grubs, heel flies, stable flies and horse flies.

"Each of these flies requires a slightly different situation in which they thrive and do economic damage to cattle. Controls vary in effectiveness and cost, as well as application methods," said Eldon Cole, a livestock specialist with University of Missouri Extension.

The blood-sucking horn fly is not viewed as an economic problem until numbers approach 200 per animal. At that point, there are many routes to follow.

Insecticidal ear tags have a good track record and can still be used, but do not apply too early in the season. The companies claim three to five months of control. Tags applied before May will be giving less than desired control during the peak fly season.

"The other concern with the fly tag is their resistant fly control. Some flies have developed a tolerance to the pesticide used in them," said Cole.

Several different products are now incorporated into the tags, and rotating tag types from year to year is helpful. Cost of the fly tags vary from 75 cents to $2 per tag.

"The older tags are pyrethroid or organophosphate and there is a new compound out this year that shows promise," said Cole.

The fly tags must be removed at the end of fly season as the low level of tag activity can contribute to the development of resistant flies. The tags also are not as popular in herds where numbered tags are used in both ears for identification purposes.

Feed-through products or oral larvacides also are popular as they do not require handling of the cattle through a chute.

"They do come at a cost and may not provide adequate control if herds across the fence are not being managed to control their horn fly problem," said Cole.

Periodic spraying is effective, but may not be practical.

"Year in and year out, self-treating devices such as back rubbers or dust bags receive the highest marks for economic control of horn flies. Regular contact with the pesticide is required, with locations in gates leading to and from water," said Cole.

The insecticides used for back rubs are usually mixed with diesel fuel, kerosene or special livestock grade mineral oil. The latter does not evaporate as quickly and is less likely to irritate the skin.

Under no conditions should cattle be allowed to use rubs that are dripping with insecticide mixes.