Ag Connection

Your link to the Universities for ag extension and research information

Volume 4, Number 7
July 1998
This Month in Ag Connection

MU Guides for more information:

G07011— Beef Cattle Lice Control

G07012 — Making and Using a Cattle Backrubber

G07013 — Protecting Cattle from Horse Flies

G07020 — Controlling External Parasites of Swine

G07030 — Fly Control in Caged Layer Buildings

G07382 — Ticks

External Parasites of Cattle
Cattle Can Have Bad Hair Days
Reflections on a Trip to Costa Rica
Filter Strips - A practical way to slow water contamination
Coming Events -
Missouri Beef Heifer Development Field Day

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External Parasites of Cattle

Failure to control external parasites costs the cattle industry millions of dollars annually. These losses may not often be apparent but can take the form of reduced weight gains and milk production, a reduction in the value of hides or just an increase in the maintenance cost of fences from cattle rubbing and scratching. There are two groups of external parasites: (1) insects (including flies, lice and mosquitoes) and (2) arachnids (ticks and mites).

Flies are pests of cattle mainly during the warmer months of the year. The shape of the mouthparts of flies determines the type of irritation inflicted upon cattle. These mouthparts may be either sponging or piercing-sucking.

The face fly is a major pest of cattle and has sponging mouth parts that are used to suck up secretions around the eyes, nostrils and mouths. Face flies are a native of Europe and were first found in this country in 1952. In serious outbreaks, there may be as many as 100 flies on a single animal. These flies are a source of constant annoyance to the animals resulting in reduced animal performance. In addition to being a constant source of irritation, they can also carry pinkeye and eyeworms. Young animals are highly susceptible to pinkeye and the results of this disease can lower the market value of affected animals.

horsefly.gif (6941 bytes)Insects that have the piercing sucking type of mouth parts include horn flies, stable flies, deerflies and horse flies. These insects pierce the animal’s skin and suck its blood. The most common of these types is the horn fly which was introduced from Europe in about 1890. Horn flies feed mainly on cattle but also attack sheep, goats, horses, swine and other animals. Horn flies congregate around the ears, flanks, withers, back and belly. High populations and the biting that result cause can cause reduction in weight gains by as much as half a pound per day and a drop in milk production of 10-20%.

Horse flies are another common blood sucking fly that annoys cattle. Under high fly populations, the average daily loss of blood from an animal can be as high as 100 ml. These flies are also capable of carrying and transmitting anaplasmosis and anthrax. The life cycle of this type of fly is interesting as the eggs are not laid in manure. Horse flies breed in water or wet soil and eggs are laid in or around ponds, lakes and streams. Larvae hatch, then burrow in mud, feeding on insects and small aquatic organisms. Sprays containing a synergized pyrethrin may repel horse flies for one to three days. No satisfactory methods for controlling horse flies have been developed.

Ticks may also attack cattle causing irritation, annoyance and a loss in vigor but, they are rarely of any economic importance in Missouri. If control is required on animals, a number of insecticide sprays are available.

Two types of lice affect cattle, the biting or chewing lice and the sucking lice and there are several species of both. Biting lice feed on hair, skin scales and blood. Sucking lice puncture the skin and feed on blood. Irritation from both of these pests cause rubbing and scratching and a loss in animal performance.

Lice spend their entire life cycle on the host animal with several generations developing through the year. Lice are spread from one animal to another through direct contact. Common locations for lice to be found on cattle include: the neck, withers, brisket, shoulders, mid-back, tailhead and behind the quarters.

(For more information on lice, see article below.)

Control methods for all these parasites are often species specific. Timing of the control method is also often critical. For example, if using fly tags, put them in early in the season to take full advantage of the time frame when the tag is effective. In some cases a combination of control methods may be tried such as tags, backrubbers, dust bags, manure sprays and feed additives.

Some flies build up rapid resistance to the active ingredient in many insecticides. It would be advisable to keep track of the type of chemicals used for fly control and vary their use from year to year. Also keep in mind what your neighbor does for fly control. If you do a good job and your neighbor does not, you will wind up controlling a lot of his or her flies.

Author: James Rogers, Livestock Specialist, Reference - Insect Pest of Farm, Garden, and Orchard, eighth edition, Ralph H. Davidson and William F. Lyon

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Cattle Can Have Bad Hair Days

Every spring, beef cattle undergo the natural effect of shedding hair. This is a natural occurrence. Some cattle tend to shed their winter hair quicker, while others maintain their hair through much of the warmer weather. The retention of hair often occurs on animals that are grazing fescue. Cattle that shed more quickly give the appearance that they’re gaining weight more rapidly.

External parasite infestation frequently causes hair loss, reduced gain, decreased feed efficiency, and susceptibility to diseases and a reduction in economic returns. There are more than one specie of cattle lice. The biting louse is reddish-brown in color with darker bands on the body. This louse has a broad, blunt and flat head and may be found on both beef and dairy animals. This louse is very mobile and moves around and through the hair on the host animal. They tend to be concentrated on the shoulders, back line of the back and around the tail head. It is more difficult to determine if lice are present on animals with black hides. Parting the hair at various locations including the top line, withers, muzzle, around the eyes, and especially the dewlap area provides the best method for determining the presence of lice.

Other lice species include the short nosed cattle louse, long nosed cattle louse, little blue cattle louse and the tail louse. These little creatures frequently are found in thick masses or areas that appear like patches on similar locations as the cattle biting louse.

It is very important to determine the source of the hair loss problem prior to making management decisions. Poor hair coat condition or loss can be caused by more than parasites. Other causes can include: natural shedding, nutrition, mineral deficiency, photosensitivity and other diseases.

There are numerous treatments on the market today for treating a broad spectrum of both external and internal parasites. Throughout the summer months take advantage of opportunities to observe your livestock. Treating for parasites can be one of the most important summer management tasks.

While you’re at it — it is important that the parasite treatment also includes face fly control. This management practice provides the opportunity to reduce the dreaded eye problem that beef producers often contend with throughout the summer months.

Author: Dale Watson, Livestock Specialist

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Reflections on a Trip to Costa Rica

In March, I was privileged to travel to Costa Rica with twelve other University of Missouri Extension Agriculture Specialists.

The purposes of the trip were to:

  1. Gain first hand experience and knowledge of a globally competitive agriculture and its implications for Missouri.
  2. Compare vastly different agricultural production technologies, management, and marketing approaches leading to an examination of different agricultural paradigms.
  3. Gain an appreciation for implications of alternative agricultural systems on rural citizens and their communities.
  4. Gain appreciation for interrelationships of world economies and societies.
  5. Gain a new awareness of how extension is organized and how educational programs are funded and delivered in another country and culture.
  6. Gain a new appreciation for developing educational programs that address diverse audiences.

We visited EARTH University, banana plantations and processing, rain forests, local families, coffee farms and processing, Extension centers, and other places.

Some of my observations from this trip:

The people are family oriented. Many don’t rely on cars. They are much more dependent on public transportation, bicycles, or walking. Many families don’t have telephones. All of this results in things not moving quite as fast as we are used to here in the United States.

We saw cooperatives for marketing coffee, bananas, plantain, pineapple, and selling crafts made from banana paper. While their cooperatives might be behind some of ours, we could use some of their ideas — especially in niche and value-added markets.

The Costa Ricans were developing new products to solve problems. For example, there is a lot of waste from banana plants. The stalks can be quite a disposal problem. A process for making banana paper was developed to reduce the waste produced and also gives them a product to sell.

They compost the waste from banana and coffee production. These were used to mulch fields, providing much needed organic matter.

We saw some unusual products. A butterfly ranch was packaging pupae to ship to various countries for displays. People from other parts of the country raised the butterflies and put the pupae in their backpacks, took a bus to the butterfly ranch and sold them the pupae for about $2.00 each.

We became aware of how U.S. policies affect other parts of the world. Our environmental regulations often determine how small farmers operate if they want to market their products in the U.S.

The destruction of rainforests is a very complicated issue with no simple solutions. We need to study this type of issue and try to understand the implications of various ways to preserve the rainforests as well as provide a way for people to make a living. Promoting only one way of solving the problem (for instance, birth control to reduce the number of peasant farmers) will not necessarily address the whole problem.

Beef cattle production suffers because of rain forest concerns. Some countries won’t accept beef that has been raised on farms that were converted from rain forests. Poor pasture on former rain forests subjects the land to erosion. These soils are low in nutrients which are quickly lost after the forest cover is removed.

Eco-tourism is an important enterprise in Costa Rica. Some tours emphasize agriculture and the practices used to prevent damage to the environment. I believe we could establish some eco-tourism in the U.S. to promote what agriculture is doing to protect the environment.

Overall, I have more interest in what is happening in agriculture globally. I realize that many things we do in this country have a dramatic effect on those in other countries, right down to the poor families trying to make a modest living on the land.

Author: Don Day, Ag. Engineering/ Information Technology Specialist

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Missouri Beef Heifer Development Field Day
Rocking 8 Cattle Company, Highway 124 & Route H, Fayette
July 18 — 4:00 p.m.                    Beef barbecue meal served.

Preparing Animals for Weaning - Richard Randle, D.V.M.
Heifer Nutrition - Doug Geppert
Using Ultrasound to Determine Pregnancy & Sex of Embryos - Dave Hardin, D.V.M.
Marketing Genetically - Steve Pemberton, D.V.M.
Marketing Quality Heifers - Bob Larson, D.V.M.

For more information, contact:
Chris Amos — 660-248-3239, Melvin Brees — 660-248-2272, Jim Underwood — 660-248-1640, or Dale Watson — 660-542-1792

Co-sponsors — University Extension Commercial Ag, Pfizer Animal Health, Moorman’s Mfg., Elanco, Pharmacia & Upjohn, Howard County Cattleman’s Association

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Filter Strips — A practical way to slow water contamination

Comparison of the economics of grass and grass/legume filter strips to corn and soybeans. Cost-share and incentive programs would affect these figures. It is also difficult to assign an economic value to the benefits of increased safety and improved water quality.
Variable Costs
(Dollars Per Acre)

(other hay)




Fertilizer & Lime










Chemicals & Supplies










Equip., Fuel, & Misc.





Machine Hire





Crop Insurance    



Total Variable Costs





Yield Per Acre

2.5 tons

2.5 tons

110 bu.

35 bu.

Price Per Unit





Gross Returns





Income before Fixed Costs





* Variable costs per acre are the 1996 costs reported by Missouri farmers who participate in the University of Missouri Extension Management Information Records (MIR) program.
Note: No interest figures included

Filter strips can help solve some of the problems created by field runoff. This runoff carries sediment, plant nutrients and crop protection products from the field into nearby surface waters. Plant nutrients and pesticides are either bound to the sediment or dissolved in the water. Properly designed and operating filter strips provide water quality protection by reducing the amount of sediment and other contaminants in the runoff.

Filter strips are areas of land covered with vegetation between the field drainage areas and the surface waters receiving the runoff. The vegetation slows the runoff which increases the amount of infiltration. Vegetation also traps sediment with its attached contaminants and also helps control erosion. Collected nutrients are used by the vegetation instead of entering the water supply. Filtered water then enters the surface water. Filter strips may also provide increased safety by moving machinery operations away from steep stream and ditch banks.

Properly managed filter strips can be a viable alternative to cropping highly erodible stream or ditch banks. Filter strips for cropland should be at least 15 feet wide, with steeper slopes requiring wider strips. They should not be used as a roadway. Small channels or rills that develop should be repaired as soon as possible.

Author: Cynthia DeOrnellis, Associate Specialist, Farm Management

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University of Missouri ExtensionAg Connection - July 1998 -- Revised: April 20, 2004