Animal Science Department

 

Date of this Version

Spring 4-21-2014

Citation

Wilken, M. F., 2014. Model development for the prediction of intake and carcass measures to be used as economic marketing determinants for calf-fed steers. Doctoral dissertation, University of Nebraska-Lincoln.

Comments

A DISSERTATION Presented to the Faculty of The Graduate College of the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Doctor of Philosophy, Major: Animal Science, Under the Supervision of Professors Larry L. Berger and Galen E. Erickson. Lincoln, Nebraska: May, 2014

Copyright (c) 2014 Mallorie F. Wilken

Abstract

Accurate prediction of intake and carcass characteristics can assist in projecting input costs and potential premiums when cattle are sold at optimum finishing so net profit/loss can be anticipated. Currently published DMI prediction equations and dietary NE values are based off of data collected over 50 years ago and have been shown to inaccurately predict intake compared to a prediction equation based of off performance data. Calculating dietary NE values from performance data increased precision and accuracy of prediction. Additionally, prediction accuracy was increased for diets containing ethanol byproducts. Since ethanol byproducts have been shown to have 110 to 140% the feeding value of corn, the improvement in predicting intake illustrated the need for research to more accurately defining feedstuff energy values via performance data and using that information to derive new intake prediction equations. Even so, predicting optimum endpoint for the producer can be the most economically beneficial prediction since carcasses are awarded premiums for high cutability and high quality grades. It has been found that predicting marbling score by measuring backfat and BW over the feeding period seems to be the most viable and accurate compared to other model combinations of backfat, BW and DMI. However, backfat and BW are not synonymous with marbling score and therefore, bias increases at the end of the feeding period. Still, the economic advantage may be given to feeding the animal longer as a greater return was found for projections of animals fed past the 1.2 cm optimum backfat. Since carcass gain can be up to 90% of total gain at the end of the feeding period, it is beneficial for the producer to feed cattle longer as the cost of gain is spread over more carcass weight. The resulting paradigm shift to feeding cattle what is deemed past industry optimum will lead to greater carcass weights, higher quality grades, and ultimately greater premiums for the producer.

Advisors: Larry L. Berger and Galen E. Erickson

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