Heritabilities and genetic correlations of selected live body measurements of purebred angus calves

Author

Charles Paul Chihasz

Date of Award

6-1980

Degree Type

Thesis

Degree Name

Master of Science

Major

Animal Science

Major Professor

R. R. Shrode

Committee Members

J. W. Holloway, G. W. Davis

Abstract

Linear body measurements as well as weights were recorded for 1588 purebred Angus bull and heifer calves for the estimation of heritability and genetic correlation. These calves were raised at the University of Tennessee Plateau Experiment Station near Crossville, Tennessee, from 1963 to 1977.

Components of variance due to sire differences from a model including birth year, age of dam, weaning age, yearling age, sex of calf and sire nested within the year were used to calculate estimates of heritability and genetic correlation.

In general, the weaning heritability estimates were higher than the yearling estimates indicating that more progress could be made by selection based on weaning traits over yearling traits. The bull calves had higher heritability estimates for yearling traits than heifer calves. However, this may be due to different feeding practices from weaning to yearling, along with different growth patterns of bulls. Heifer calves had higher heritability estimates of calculated traits in all cases.

In the genetic correlation analysis of yearling weight with weaning traits, no trends were apparent; and some values were much higher than the theoretical upper limit (1.0), but this is not unusual in estimates from beef cattle data. The deviation of some of the estimates above 1.0 aresurelytoolargetobeattributedentirelytosamplingerror. This casts some doubt on the reliability of all the estimates even those which are of theoretically possible magnitude. The theoretically possible estimates were high (0.50 to 1.0) for pooled birth weight, weaning weight and post weaning gain. The other estimates were intermediate (0.20 to 0.49) for pooled weaning heart girth and volume, and heifer birth weight and weaning length.

Recommended Citation

Chihasz, Charles Paul, "Heritabilities and genetic correlations of selected live body measurements of purebred angus calves. " Master's Thesis, University of Tennessee, 1980.
https://trace.tennessee.edu/utk_gradthes/7773