Cattle are not passive hosts to the various flies pestering them. They do fight back. Defensive behaviors are reactions to specific flies in the pasture. Each fly species has a preferred landing site. You can tell what kind of flies are attacking cattle by their reactions and the distribution of flies over their bodies. Responses depend on the annoyance and pain inflicted by the pest.

Stable flies

Stable flies possess a large bloodsucking proboscis, feed once or twice a day and inflict a bite many times more painful than that of a mosquito. They prefer to bite cattle’s legs and bellies. Cattle react by foot stomping, tail switching, bunching and spending a long time in water to try to protect themselves.

Stable flies remain on hosts long enough to feed but, because of the painful bites and cattle’s defensive reactions, feeding is often interrupted. Each fly has to visit the same or different hosts several times to obtain a full blood meal.

Horn flies

Horn fly mouthparts, also developed for blood sucking, are smaller than those of stable flies. Each female horn fly feeds up to 40 times a day, inserting its proboscis into the skin at least that many times.

Horn flies spend all of their time on their hosts, leaving for short periods to lay eggs on fecal pats just deposited by their hosts. Flies that spend a long time on cattle can be controlled by applying insecticide to the body.

In the summer as temperatures rise throughout the day, horn flies move down cattle’s sides. Small clouds of flies rise over their backs causing them to switch their tails or toss their heads. Disturbed into flight, horn flies land on the same or neighboring cattle with many flies exchanged among them. Consequently, not all members of the herd need to be treated with insecticides because every fly eventually lands on a treated host and is killed.

Cattle react to horn fly attack by switching tails over backs (rump), throwing heads over shoulders and bunching. Bunching caused by stable flies differs from that caused by horn flies. Cattle bunched by horn flies throw their heads over their backs, while cattle bunched by stable flies do a lot of foot stomping.

In addition, stable fly attacks most often result in cattle bunching at corners of pastures, a behavior seldom seen in cattle attacked by horn flies. The shorter time stable flies spend on their hosts makes protection from them difficult.

Horn flies’ closer association with their host makes it easier to control them with insecticides.

Face flies and houseflies

Face flies are indistinguishable from houseflies. They possess sponging mouthparts and cannot obtain food by sucking blood from their hosts. They can only feed on serum/blood secretions from pre-existing wounds. After landing on the host’s face, face flies move immediately to the eyes; houseflies move to the nostrils and mouth. However, face flies’ mouthparts are armed with sharp teeth used for scraping conjunctival tissues. This increases production of tears that run down cattle cheeks and are visible when dust collects on them. Face flies visit their hosts one to two times a day for short periods of time. This behavior and the sensitive body areas visited make insecticidal control difficult.

Cattle pestered by face flies react by flapping ears and shaking their heads from side to side. Houseflies do not harm cattle and cause little defensive behavior.

This information was reprinted with permission from the Summer 2006 Kansas Veterinary Quarterly.

Temperament of cattle

“Temperament,” “docility” and “disposition” are used to describe cattle behavior. Temperament is the manner of thinking, behaving or reacting characteristic of a specific individual. “In stockman parlance, we use the terms ‘docile’ and ‘tractable’ describe cattle that are easily taught, handled, worked, managed and/or controlled, and the term ‘temperamental’ to describe cattle that are excessively sensitive, irritable, excitable or angered,” explains Gary Smith, PhD, Colorado State University distinguished professor.

Smith says colloquialisms for “disposition” range from “mild” (so gentle you can’t make ’em move) to “wild” (will eat your lunch).

Scientific studies on docility of cattle started in earnest in the last 20 years. Production and end-product traits affected by temperament are:

  • In the feedlot — docile cattle have greater growth rates, feed intake, rate of gain, feed conversion ratios and final weights; temperamental cattle have higher rates of injury, morbidity and mortality.
  • In the cooler and kitchen — docile cattle have higher dressing percentages, produce carcasses of higher quality grade and beef that is more tender; temperamental cattle have higher incidences of dark-cutting beef, and greater trim loss (from loin, round and rump) due to bruise damage.
  • In immune response, conception and lactation — docile cattle show greater response to, and sustained antibody levels from, vaccines; temperamental cattle have lower AI pregnancy rates and lower milk production.

Measuring cattle temperament

All methods for measuring temperament involve restraint. These include:

  • Subjective evaluations while animals are in pens (pen scores), in chutes (chute scores), or leaving chutes (visual flight or exit speed).
  • Objective measurements of the velocity at which an animal leaves a restraining device, usually a squeeze-chute (flight or exit speed).

    Beef Improvement Federation-recommended chute temperament scores and descriptions are as follows:

  • Score 1: Docile. Mild disposition. Gentle and easily handled. Stands and moves slowly during processing. Undisturbed, settled, somewhat dull. Does not pull on headgate when in chute. Exits chute calmly.
  • Score 2: Restless. Quieter than average but may be stubborn during processing. May try to back out of chute or pull back on headgate. Some flicking of tail. Exits chute promptly.
  • Score 3: Nervous. Typical temperament is manageable, but nervous and impatient. A moderate amount of struggling, movement and tail flicking. Repeated pushing and pulling on headgate. Exits chute briskly.
  • Score 4: Flighty (wild). Jumpy and out of control; quivers and struggles violently. May bellow and froth at the mouth. Continuous tail flicking. Defecates and urinates during processing. Frantically runs fence line and may jump when penned individually. Exhibits long flight distance and exits chute wildly.
  • Score 5: Aggressive. May be similar to Score 4, but with added aggressive behavior, fearfulness, extreme agitation, and continuous movement which may include jumping and bellowing while in the chute. Exits chute frantically and may exhibit attack behavior when handled alone.
  • Score 6: Very Aggressive. Extremely aggressive temperament. Thrashes about or attacks wildly when confined in small tight places. Pronounced attack behavior.

Temple Grandin, PhD, Colorado State University, recommends chute scores of 1 = calm (0–1 body shakes), 2 = restless (2 body shakes), 3 = moderate (3 or more body shakes) and 4 = violent struggling or rearing, but believes that scoring cattle for exit speed from a squeeze chute with a simple “walk” = 1, “trot” = 2 or “run” = 3 may be a more sensitive indicator of temperament. She also believes that the location of the hair whorl on the forehead of cattle is associated with temperament; cattle with hair whorls above the midpoint of the eyes are more susceptible to excitement than are cattle with hair whorls below the midpoint of the eyes.

This information was presented at the 2007 Western Veterinary Conference.