Masters Theses

Teri L. Ingle

Date of Award

8-1988

Degree Type

Thesis

Degree Name

Master of Science

Major

Animal Science

Major Professor

J.C. Waller

Committee Members

J.B. McLaren, M.J. Riemann

Abstract

The objective of this experiment was to determine the feasibility of utilizing certain feeder calf characteristics to predict subsequent feedlot performance and carcass value. Data from 144 steers (72 Angus and 72 Angus-Hereford cross) in Trial I (1984-85) and 144 steers (same distribution of breeds) in Trial II (1985-86), purchased by an order buyer from East Tennessee and the surrounding area, formed the basis of this study. Animals were considered to be representative of the predominate breeds preferred by buyers of Tennessee feeder steers. Initial and final linear body measurements, subcutaneous fat thickness and weights were recorded for the growth phase in each Trial. Carcass traits and days on feed needed to reach 12 mm fat thickness were recorded for the finish phase of Trials I and II.

In Trial I, initial width (P < .001) and average daily gain during the growth phase (P < .01) significantly effected subsequent carcass value. These variables were therefore utilized to allot the steers on Trial II to feedlot pens. These allotment systems proved to be effective in predicting days on feed needed to reach optimal slaughter endpoint of 12 mm fat thickness (P < .01). However, no differences in the effectiveness of predicting days on feed were found between the two allotment systems.

The results of analysis of variance on the combined data set from Trials I and II indicated that an increase in final height, initial length, initial width and total weight gain during the growth phase significantly increased subsequent carcass value (P < .001). An increase in final fat thickness at the end of the growth phase also increased carcass value (P < .0001). Neither initial height, final shoulder width, final length or initial fat thickness had any effect on carcass value.

An increase in initial and final fat thickness significantly decreased the number of days on feed needed to reach optimal slaughter endpoint (P < .0001). An increase in final shoulder width also decreased days on feed (P < .01). However, initial and final height, initial and final length, initial shoulder width and total weight gain during the growth phase had no significant effect on days on feed.

By grouping the animals in Trials I and II by net worth, it was determined that animals with higher linear body measurements and weight gains during the growth phase yielded higher carcass values due to the increase in carcass weight. The animals with lower linear body measurements and total weight gains during the growth phase required fewer average days on feed to reach optimal slaughter endpoint, however they yielded carcasses of lower values due to lower carcass weights.

Initial shoulder width and weight gains during the growth phase can be an accurate predictors of subsequent feedlot performance and carcass value. Initial length and final height may be utilized as predictors of carcass value, also, after further study.

Initial width and/or weight gain during the growth phase could be useful to the feedlot operator in predicting feedlot performance and carcass value of feeder steers of British breeds. Linear body measurements and weight gains might also be useful to the beef producer in selecting management techniques and marketing strategies to increase net revenue.

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