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External Parasite Control May Reduce the Chances of Pinkeye and Anaplasmosis in Cattle

STOCKTON — Anaplasmosis and pinkeye are cattle problems that negatively impact the health, performance, and profit potential of the cattle operation according to University of Missouri Extension Livestock Field Specialist Patrick Davis.

“External parasite control may help reduce these problems,” said Davis.

Causative agents of pinkeye include bacterial agents Moraxella bovis, Moraxella ovis, Moraxella bovoculi, and mycoplasma species. Face flies transmit pinkeye causative agents in cattle.

“Reducing face flies potentially reduces pinkeye problems,” says Davis.

Some of the methods available include sprays, backrubbers, dust bags, feed additives, insecticide boluses, and fly tags.

Anaplasma marginale is the bacteria that causes anaplasmosis in cattle. The external parasite vectors associated with transmission of this disease include horse flies and ticks. More information related to this disease in cattle can be found in MU Extension guide sheet G7705 at any county extension office or online at

“Insecticidal and or natural horse fly control is hard to do in a commercial beef cattle operation,” said Davis.

Since insecticides have to be provided daily the only practical way to provide insecticidal control on horse flies is using an automatic treadle-type sprayer where the cattle pass through it daily.

A natural way to control horse flies is to construct an umbrella or Manitoba-type horse fly trap. This horse fly trap has shown measurable horse fly control for a few cattle. However, for large herds you may need to construct several traps to reduce biting problems.

More information on horse fly control methods in cattle and the construction of tools to aid in control can be found in MU Extension Guide Sheet G7013.

“Ticks are also a vector involved in the transmission of Anaplasmosis so their control may be useful in reducing this problem,” said Davis.

Sprays, pour-ons and fly tag products are approved for tick control.

“Consulting a veterinarian to help advise and devise an external parasite control plan to help reduce problems with pinkeye and anaplasmosis is a good idea,” said Davis. “This relationship is needed to receive a veterinary feed directive to feed chlortetracycline to cattle, which is used to control anaplasmosis.”

For more information on reducing the chances of pinkeye and anaplasmosis in cattle, contact any of the MU Extension livestock field specialists in southwest Missouri: Eldon Cole in Lawrence County, (417) 466-3102; Andy McCorkill in Dallas County at (417) 345-7551; Elizabeth Picking in Howell County at (417) 256-2391 or Dr. Patrick Davis in Cedar County at (417) 276-3313.