Pest Management

Insects; Pests of Cattle: Know the enemy in external parasite season! YOUR CATTLE WILL KNOW BEFORE YOU!!

Insecticides are commonly used to control the external parasites in cattle. there are a variety of application methods for these chemicals. A producer decides which to use based on the level of infestation and the opportunity to apply the insecticide. Insecticides labeled for cattle are prepared as a dust, wettable powder, emulifiable concentrate, liquid suspension, aerosols, systemic pour-on insecticides, ear tags, stomach bolus and oral mixed with feed. Each of these formulations has its own unique application method.

Horn flies are slightly smaller than houseflies and may cause considerable damage to cattle. They are bloodsuckers and feed on the shoulders, neck and back of cattle. They may also feed around the horns where they attach to the skull. Horn flies remain on the cow night and day and only leave the animal to lay eggs in fresh manure. They will move from animal to animal when they are in close proximity. Horn flies have been treated with insecticides for the past 50 years

They will develop in moist, decaying vegetation such as piles of silage, bedding with straw and manure. Keeping bedding and feeding areas free of decaying material will help control stable flies. Spraying these areas with pyrethroids will also help to control them.

These flies are very annoying to cattle but also play a a role in the transmission of Maraxella bovis, which is the causal agent of bovine pinkeye. Best coverage occurs when the dust bag is positioned so the animal must use its head to lift it, thereby treating the face and head. Ear tags treated with insecticide are also effective at treating face flies.

Deer and horse flies are called tabanids and are a large diverse group of blood-feeding flies. Their mouthparts are blade-like and they inflict a painful bite when feeding. The painful bite usually draws a response from the animal that interrupts feeding, and the fly bites again. Deer flies readily feed on humans, companion animals, livestock and wildlife, while horse flies are a serious pest of livestock but rarely attack humans. Tabanids have been reported to reduce weight gains and spread diseases. the wound from tabanids is so severe the animal will continue to bleed after the flies have fed.

Ticks are commonly thought of as insects, but are actually arachnids. Ticks cause serious livestock losses in the southern part of the U.S., but are found in northern regions as well. Ticks affect cattle through blood loss, reduced weight gains, transmission of diseases such as anaplasmosis and damage to fleece or hide. Several types of insecticides are effective at treating ticks and may be labeled as araricides. Check labels closely to make sure they are labeled for tick control.

Cattle lice are found throughout the U.S. in several different species. Some suck blood while others cause scabs on the skin from feeding on the external skin layers. Lice are commonly found in larger numbers in the cooler months, even winter. They cause skin irritation to the point that cattle will rub the hair off of areas, which results in bare patches of skin. Lice are effectively controlled through systemic pour-ons, sprays and dust.

Reference: Progressive Cattleman magazine May 2011, www.progressivecattle.com - Kraig Peel, Assistant Professor Colorado State University, Kraig.Peel@colostate.edu