Dr. Joe

Pest Management Considerations for your Operation

By Joseph W. Ward, Ph.D

  For Livestock farmers, dealing with pests’ ins one of the most expensive and time consuming chores that comes with raising healthy livestock.  A variety of insect and mite pests affect the cattle industry.  House flies, stable flies, face flies, horse flies, deer flies, cattle grubs, lice, and mange mites all are common and significant pests of cattle.  Many factors come in to play in both preventing and fighting pests, including the time of the year, the type pf animal and the conditions in which animals live and are raised.  Experienced farmers know that pests and livestock predators are more than a mere annoyance that can have a direct impact on the operation’s bottom line.
  Of course specific problems with predators and pests can vary depending on the type of livestock and your geographical location.  Most cattle farmers find that internal parasites or worms are the most financially damaging pests.  Pasture stocking densities and the more pasture is used, the more likely it will be infected.  Preventing overgrazing can be somewhat problematic and difficult to prevent due to weather, geographical location, and available pasture acres.  When possible, it is best to rotationally graze pasture acres to interrupt pest biological cycles thus reducing pest infestations on pasture acres.
  Insect and mite pest activity can result in lowered milk production levels and reduce feed conversion efficiency.  Pest activity exposes cattle to pathogenic microorganisms and causes blood loss and hide damage.  It can lead to public health and public nuisance concerns.   Often, insect and mite pressure can add to unwarranted stressors on young replacement animals that can delay their entry into production and adversely affecting lifelong production performance.  As herd sizes continue to increase on farms, pest pressures often are aggravated by large quantities of animal waste that must be handled.  Crowded conditions can promote the spread of external parasites.  
  Historically, management of cattle pests often has relied on insecticide use as a single control tactic.  This single approach can aggravate insecticide resistance problems in pest populations and inadvertently destroy natural enemies of the target species.    Many producers are implementing integrated pest management programs to maximize the effectiveness of pest control actions whole conserving beneficial insects and minimizing pesticide use.  Extension area specialists are a good source for information on effective IPM programs (Integrated pest management programs).  This program’s concept is to use the right type pf control at the right time for the right duration to control pests effectively.
  There are a range of cattle internal and external parasite control products available on the market.  Collecting fecal and skin scrapping samples and having your local veterinarian examine the samples to determine the type of parasite present on your operation is always a good practice.  Costly mistakes using the wrong pest control products can be avoided by determining the type and level of pest infestation through proper testing methods.
  Particularly in warmer climates, flies are the most common cattle pest.  Flies including common house files, face flies, bot flies, horse and deer flies and horn flies.  Horn flies can be the most expensive to control.  Horn files bite through the cattle’s skin and can suck upwards of a pint of blood a day.  Heavy infestation is not only irritating to the animals, but the files can weaken cattle slowing their growth and production efficiencies.  
  Horn flies are gray and look like small houseflies.  Horn flies bite and spend most of their time clustered around the head, shoulders and back of cattle.  These blood-sucking flies feed up to 30 times per day.  This constant biting cause cattle pain and stress, and research has shown that it can reduce cattle gains by as much as 20 pounds during the feedlot period.
  The life cycle of the horn fly ranges from 10 to 20 days, depending on weather conditions.  Populations will typically peak in midsummer and early fall.  University research has reported that when the fly counts reach 200 flies per animal, the economic threshold had been reached and animals will have significant weight loss.  Economic threshold is the pest density at which producers should take action to manage the pest.
  Face flies look like large dark, house flies.  They are the on-biting flies that feed on animal secretions, plant nectar and manure liquids.  Face flies may transmit pathogens responsible for infecting the eye and causing keratoconjunctivitis or pink eye in cattle.  Cattle with white around the eyes are more susceptible to pink eye than their black-eyed counter parts, as the flies are more attracted to the cattle’s eye fluids.  Flies spread the disease from one animal to the next. Producers can vaccinate their cows for pink and fly control will help stop the spread of the disease. The life cycle of a face fly is approximately 21 days and populations tend to peak in late summer.
  Louse populations are usually kept under control with the proper use of preventive insecticides.  Keeping areas well-ventilated helps to prevent problem. If a herd is introduced to an infected animal, the lice can spread.  Cattle lice are most commonly found on the top of the head shoulders, back, neck, and rump.  Infestations are usually light in the summer and heavy in the winter and early spring.
  Cattle grubs are another pest that have a major impact on cattle farmers.  As adults, grubs disturb the cattle, as larvae, they damage the meat and the hides.  According to the University of Wisconsin Cooperative Extension Service, applying insecticides before cattle are 6 months of age has shown to be the best effective method of control.  
  Mange is a winter time disease caused by mites which are highly contagious.  If an issue is observed, the infected animals should be immediately isolated from the herd.  Consult your farm veterinarian for proper treatment.  Although chemical controls are available, in severe cases, farmers are advised to sell and/or slaughter mange-infected animals to remove them from the herd.
  The goal of pest control is to reduce pest to an acceptable level.  A few of the more common methods for fly control include misters, sprays, pour-ons, dust bags, ear tags and mineral blocks.  Ear tags contain insecticides that are release slowly in the animals’ hair by movement, so ear tags shouldn’t be applied until fly populations are nearing economic thresholds (typically mid-June to July).  Pour-ons and sprays must be applied every two weeks to three weeks during the fly season to achieve proper fly control.  
  Feed additives insecticides can be included in mineral formulation for cattle.  The additives pass through the animal’s digestive tract and destroy the developing fly maggots in the manure.  Theses additives appear to be effective in killing 80 to 90 percent of the developing fly larvae in animals that have consumed the product.  Feed additives should not be offered until flies emerge in late June or July.  Research has shown that the continuous use of these products will speed up resistance in the fly populations. Back rubbers, dusters and other means of delivering insecticides, as well as non-chemical fly traps and reliance on natural fly defense mechanisms (dung beetle control of larvae) are also options.  Farmers need to watch for economic thresholds and determine what control measures will work best for their operations.  Although, total pest eradication is an unrealistic goal for most farms, unwanted pests can be very costly to a farm’s bottom line.  Producers can reduce costly mistakes by following principles of integrated pest management.  Applying the appropriate products at the appropriate time is the most cost effective approach for controlling pest and reducing economic production losses.  

The author, Joseph W. Ward, has a BS in Animal Science, a MS in Animal Nutrition from Purdue University and a Ph.D. from Oklahoma State University in Ruminant Nutrition.  Born and raised in Indiana on a livestock farm, Dr. Ward has consulted in Europe, the Far East, Oceania, and South Africa.  He has been active in animal production and animal feed manufacturing/processing since the early 80’s.  He is an organic inspector for crops, livestock and processing.  Currently, he serves as North America Product Manager for Phileo Lesaffre Animal Care. Dr. Joe can be reached at j.ward@phileo.lesaffre.com.