Word of mouth and rumor mill has historically been the basis of differentiating temperament on cattle to this point. Through data collection by breeders and the analysis of that data, a factual means to describe temperament differences in Angus cattle is now a reality.

Cattle behavior has been documented to influence economically important traits. Researchers at Colorado State University have studied cattle temperament as related to beef cattle production systems, handling facilities, and carcass end-product. Data from the Iowa Tri-County Steer Carcass Futurity reflects a difference of $62.19 per head in the net dollars returned between the most docile category versus the most aggressive category of cattle evaluated. Quality grade was also greatly enhanced in the more docile cattle, with double the percentage of carcasses grading Prime and Premium Choice.

Producers typically place some emphasis on bull behavior as part of their selection criteria for breeding stock. Surveys of commercial cow-calf producers rank disposition in the same magnitude of importance as a trait such as calving ease in selecting bulls for use in their programs. Over the past few years, Angus breeders have been submitting yearling cattle temperament scores on a 1-6 scale. The scoring system is given below:

6-point Scoring System
(Yearling cattle; age 320-440 days)
	Code	Description
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.
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.
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.

Background

At the September 2007 Board meeting, Directors approved the release of a research Angus docility genetic evaluation as part of the Spring 2008 National Cattle Evaluation, with a listing of sires having a minimum .20 accuracy and at least 10 progeny and two groups.

In the current report, the sire listing criteria have been updated to a minimum .35 accuracy and at least 15 progeny and two groups. This Fall 2008 research report contains docility EPDs for 543 sires. Sire EPDs for docility are provided in the web-based listing or in the downloadable spreadsheet.

Genetic Parameters

Heritability estimates for temperament in beef and dairy cattle tend to be moderate to high, indicating that selection for improved temperament would be effective. Heritability estimates can range from zero to 1. As a comparison with other traits, reproductive traits tend to be lowly heritable and carcass traits are more highly heritable.

Yearling cattle temperament scores processed through AHIR were edited to explore the genetic parameters for docility and the potential for a docility EPD. University of Missouri scientist Bob Weaber analyzed the dataset to calculate temperament heritability estimates, which ranged from .36 to .45. Estimates of maternal heritability were near zero. The variance components generated from this research were used in an in-house genetic evaluation for the trait, representing a heritability equal to .37.

EPD Research

An edited performance file of AHIR temperament scores was used with a four generation pedigree to calculate a docility EPD. Four categories were used, for scores 1, 2, 3, and the combined category of scores 4, 5, and 6.

The contemporary group was defined in a similar format to the Association's national cattle evaluation for yearling weight. Groups without any variation in temperament scores were removed from the analysis. There were 5,364 contemporary groups represented in 56,463 temperament scores. The animal model evaluation included contemporary group, age of dam classes 2 yr through 10 yr, linear effects of calf age deviated from 365, and categorical temperament scores. The evaluation produced 185,499 EPDs calculated for parents, nonparents with individual records, and pedigree ties (Table 1).

Table 1. Descriptive statistics for docility genetic evaluation

Results

The Docility EPD is presented as a percentage, similar to the concept used in heifer pregnancy EPDs. A higher value is considered more favorable in terms of docile temperament. Since this is a threshold trait, herds that exhibit no problems in temperament will realize no improvement in selecting for favorable docility EPDs.

Table 1 illustrates a sizeable spread between the most and least docile current sire EPDs. Figure 1 provides a distribution of EPDs for the current sires. The docility EPDs tended to be positively correlated with yearling weight EPD, but not with other performance and carcass traits. The genetic trend for this new prototype EPD is essentially flat, when reviewing the average EPD by birth year for animals in the evaluation.

Figure 1. Distribution of Docility EPDs for Current Sires

Figure 2 depicts an example percentile breakdown for the docility EPDs for the current sires in the research project. As with all percentile rankings, these values are to be used as a guide to determine where an individual of interest falls within a particular class of animals, in this case the 5,200 current sires with EPDs.

Figure 2. Example Percentile Breakdown for Docility EPDs in Current Sires

Use of Docility EPDs

Docility EPDs can be used as part of a complete selection program in the event that a breeder needs to make improvement in a herd's cattle temperament. In the following example, a 10% difference exists between the EPDs for Bull A and Bull B. On the average, assuming the two bulls were mated to comparable females, one would expect 10 more calves out of 100 sired by Bull A to have a temperament in the most docile score (score=1) compared with calves sired by Bull B. In herds where temperament problems are not an issue, this expected difference would not be realized.

					Bull A	+13%
					Bull B	+3%
					Difference	10%

Summary

Sire EPDs and accuracies can be downloaded into a spreadsheet format and sorted as desired. Breeders may also request a printed version of the report if needed, by contacting the Performance Programs Department at 816-383-5100.

Click here to view sires.