M. Breck Long

Document Type

Thesis - University Access Only

Award Date

1994

Degree Name

Master of Science (MS)

Department / School

Animal Science

First Advisor

Donald M. Marshall

Abstract

Performance records from 1982 to 1992 on 1365 calves for birth weight (BW) and 1492 calves for weaning weight (WW) were analyzed to estimate relationships of purebred sire expected progeny difference (EPD) values for BW and WW to actual crossbred progeny performance. Progeny dam breeds evaluated were straightbred Hereford, F1 Salers x Hereford, and three two-breed rotations (Simmental x Hereford, Angus x Hereford, and Tarentaise x Hereford). Sires of the calves were Polled Hereford, Simmental, Angus, Salers, Tarentaise, or Charolais. The pooled-across-breed regressions (kilograms/kilogram+ SE) of BW and WW of calves on sire EPD were 1.17 + .31 and .75 + .28, respectively. The regression coefficients were similar to the expected value of 1.0. Residual correlations between BW and BW EPD and WW and WW EPD were .16 (P < .01) and .05 (P = .10). Additional regression and residual correlation analyses were conducted in which records from progeny of low-accuracy sires (Acc. < .50) were deleted. The reduced data set included 967 records for BW and 962 records for WW. The pooled-across-breed regressions (kilograms/kilogram + SE) of BW and WW of calves on higher-accuracy sire EPD were 1.28 + .35 and .71 + .31, respectively. The regression coefficients were similar to the expected value of 1.0. Residual correlations using higher-accuracy sire data between BW and BW EPD and WW and WW EPD were .18 (P < .01) and .09 (P = .02). Breeders who use BW and WW EPDs as a selection tool should expect such selection to be effective, on average, and reasonably consistent with theoretical expectation.

Library of Congress Subject Headings

Beef cattle -- Breeding
Calves -- Performance records
Calves -- Weight

Format

application/pdf

Publisher

South Dakota State University

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Rights Statement

In Copyright