Masters Theses

Date of Award

6-1972

Degree Type

Thesis

Degree Name

Master of Science

Major

Animal Husbandry

Major Professor

Haley M. Jamison

Committee Members

J.B. McLaren, William R. Backus

Abstract

Lifetime performance and sale records of 688 purebred, Angus, Hereford and Polled Hereford bulls, developed on breeder's farms and consigned to the Tennessee Breeders' Performance Tested Bull Sales during the 5-year period (1966-1971) were utilized in this study. In order to be eligible for these sales a bull had to have minimum requirements with reference to growth rate from birth to weaning, lifetime weight per day of age, type grades at weaning and at the end of the post-weaning test. All bulls were full fed for a period of 98 days.

The objective of this study was to ascertain the most important factor or factors influencing the selling price of bulls sold in performance tested sales.

A preliminary analyses on a within-year-sale location by breed indicated no apparent difference between breeds for any of the traits studied. In the final analyses, variation in the dependent variable, selling price of the bulls, was considered to be due to variation in seven independent variables. In order to assess the influence of each of the independent variables, after other variables had been considered, the order of incorporation into a regression model was based on the practical sequence of these variables in evaluating performance. This order was; (1) weight off test, (2) average daily gain on full feed, (3) age at the end of test, (4) lifetime weight per day of age, (5) average daily gain from birth to weaning, (6) adjusted average daily gain from birth to weaning, and (7) age at weaning.

The seven performance traits explained 60.4 percent of the variation in the selling price of performance tested bulls. Weight off test alone explained 28.6 percent of the variation in the selling price whereas average daily gain on full feed added only 11.0 percent to the explanation of the variation.

Grade at weaning had a significant effect (P<.01) on the selling price of performance tested bulls. Bulls grading average fancy at weaning, on the average, sold from $194.44 more than bulls grading low choice. However, when weaning grade alone was included in the model the R2 value was only .024. Although the differences between grade at weaning on selling price was significant very little if any variation was explained. Final type grade had a significant effect (P<.01) on the selling price of performance tested bulls. These data indicate that bulls grading low choice at the end of the test sold for $474.94 less than bulls grading average fancy. When final type grade was included the R2 value was only .168.

In Analysis III final type grade was included as a discrete variable with age at the end of the test and lifetime-weight-per-day-of- age as continuous independent variables. Final type grade had a significant effect on the selling price of performance tested bulls. Bulls grading average fancy within the range of these data, sold on the average for $382.43 more than bulls grading low choice. When selling price was regressed on age at the end of the test, these data indicate that on the average for each increase in days of age above the mean. that selling price increased $1.53. Lifetime-weight per day of age was also a significant (P<.01) source of variation. These data indicate that on the average for each unit of increase in lifetime-weight-per-day-of-age that selling price increased $527.94. These findings indicate that those individuals buying Breeders' Performance Tested bulls were concerned with final type grade, age at the end of the test as well as lifetime-weight- per-day-of-age.

Final type grade in Analysis IV had a significant (P<.01) effect on the selling price received of performance tested bulls. Weight off test as well as lifetime-weight per day of age when included as a continuous variable had a significant effect (P<.01) on the price received for the sale of performance tested bulls. The R value of .438 indicates the variation that was accounted for by the inclusion of these independent variables. These data indicate that buyers of performance tested bulls were interested in the individual performance data presented in the catalog but tended to let conformation, size, as described by weight, and age influence them in their final decision.

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