Docility

From BIF Guidelines Wiki

Important behaviors to beef cattle production include reactions to processing through a squeeze chute, maternal instincts at calving, newborn calf vigor, bull serving capacity, and foraging behavior. Because these are distinctly different behaviors, different strategies are necessary to quantify differences among animals. Among the most important of behavioral traits, temperament reflects the ease with which animals respond to handling, treatment, and routine management. Animals with disposition problems are a safety risk to handlers, themselves, and other animals in the herd. Disposition affects handling equipment requirements, operation liability exposure, Beef Quality Assurance, and performance.

Chute Scoring

The docility score provided below is designed to subjectively evaluate differences in disposition when animals are processed through the squeeze chute. Because an animal’s behavior can be influenced by past experiences, scoring should be conducted at weaning or yearling ages. This will reduce the extent to which current behavior has been influenced by prior handling experiences. Scores should be collected while calves are restrained with headgates but without having motion restricted by squeeze.

Descriptions of Chute Scores are:

  1. Docile. Mild disposition. Gentle and easily handled. Stands and moves slowly during processing. Undisturbed, settled, somewhat dull. It does not pull on headgate when in chute. Exits chute calmly.
  2. Restless. Quieter than average, but maybe stubborn during processing. May try to back out of chute or pull back on headgate. Some flicking of tail. Exits chute promptly.
  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.
  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
  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 chute. Exits chute frantically and may exhibit attack behavior when handled alone.
  6. Very Aggressive. Extremely aggressive temperament. Thrashes about or attacks wildly when confined in small, tight places. Pronounced attack behavior

Exit Velocity

In addition to chute scores, researchers have evaluated flight speed or exit velocity (EV), the velocity at which and animal leaves a restraining device such as a squeeze chute. EV can either be measured objectively in seconds using a photo electronic device or subjectively by visual appraisal using a six point categorical scale from 1 = slow to 6 = very fast. In using electronic equipment the first timing trigger is often placed 6 feet beyond the headgate and the second timing trigger is often placed 12 feet from the headgate (6 feet between start and stop trigger). Elapsed times are converted to velocity by diving the distance by the elapsed time. The heritability is increased considerably by averaging 2 or 3 flight speed scores.

Pen Scoring

Another method of temperament measurement is Pen Score. Animals are penned in a small lot (approximately 12 feet X 24 feet) in small groups (n~=5) and approached by two observers. The individual animal’s response to human approach is scored on a scale from 1 to 5 as follows:

  1. Non-aggressive (docile) Walks slowly, can be approached closely by humans, not excited by humans or facilities
  2. Slightly Aggressive Runs along fences, will stand in corner if humans stay away, may pace fence
  3. Moderately Aggressive Runs along fences, head up and will run if humans move closer, stops before hitting gates and fences, avoids humans
  4. Aggressive Runs, stays in back of group, head high and very aware of humans, may run into fences and gates even with some distance, will likely run into fences if alone in pen
  5. Very Aggressive Excited, runs into fences, runs over humans and anything else in path, “crazy”

Genetic Evaluation

Genetic evaluations for docility are conducted in a single-trait analysis using a linear model fit to score category values. No repeated measures are fit. If an animal has both a weaning and yearling docility score than the weaning score is used. The contemporary group is included as the group at weaning (if a weaning observation) or yearling (if a yearling observation). The EPD should be published on the docility-score scale.

Summary

Temperament traits have been shown to be moderately heritable, with magnitudes similar to heritability of growth traits. These measures should be treated as separate traits. Positive correlations between chute scores, pen scores, and exit velocity have been reported.