Journal of Animal Science, Vol 69, Issue 3 985-992, Copyright © 1991 by American Society of Animal Science

JOURNAL ARTICLE

Estimates of genetic parameters for live animal ultrasound, actual carcass data, and growth traits in beef cattle

J. W. Arnold, J. K. Bertrand, L. L. Benyshek and C. Ludwig
Anim. and Dairy Sci. Dept., University of Georgia, Athens 30602.

Growth and carcass measurements were made on 2,411 Hereford steers slaughtered at a constant weight from a designed reference sire program involving 137 sires. A second data set consisted of ultrasound measures of backfat (USFAT) and longissimus muscle area (USREA) from 3,482 yearling Hereford cattle representing 441 sires. Restricted maximum likelihood procedures were used to estimate genetic parameters among carcass traits and live animal weight traits from these two separate data sets. Heritability estimates for the slaughter weight constant steer carcass backfat (FAT) and longissimus muscle area (REA) were .49 and .46, respectively. In addition, FAT had a negative genetic correlation with REA (-.37), weaning weight (-.28), and yearling weight (-.13) but positive with marbling (.19) and carcass weight (.36). Marbling was moderately heritable (.35) and highly correlated with total postweaning average daily gain (.54) and feedlot relative growth rate (.62). Heritability estimates for weight constant USFAT and USREA were .26 and .25, respectively. The genetic correlation between weight constant USFAT and USREA was positive (.39), indicating that in these young animals USFAT does not seem to be an indication of maturity. Mean USFAT measures and variability were small (.48 +/- .17 cm, n = 3,482). Results indicate that carcass fat on slaughter steers and ultrasound measures of backfat on young breeding animals may have different relationships with growth and muscling. These relationships need to be explored before wide scale selection based on ultrasound is implemented.

This article has been cited by other articles:

				A. K. Kahi, T. Oguni, Y. Sumio, and H. Hirooka Genetic relationships between growth and carcass traits and profitability in Japanese Brown cattle J Anim Sci, February 1, 2007; 85(2): 348 - 355. [Abstract] [Full Text] [PDF]

				A. Rios-Utrera, L. V. Cundiff, K. E. Gregory, R. M. Koch, M. E. Dikeman, M. Koohmaraie, and L. D. Van Vleck Genetic analysis of carcass traits of steers adjusted to age, weight, or fat thickness slaughter endpoints J Anim Sci, April 1, 2005; 83(4): 764 - 776. [Abstract] [Full Text] [PDF]

				T. L. Wheeler, L. V. Cundiff, S. D. Shackelford, and M. Koohmaraie Characterization of biological types of cattle (Cycle VII): Carcass, yield, and longissimus palatability traits J Anim Sci, January 1, 2005; 83(1): 196 - 207. [Abstract] [Full Text] [PDF]

				M. E. Davis, S. L. Boyles, S. J. Moeller, and R. C. M. Simmen Genetic parameter estimates for serum insulin-like growth factor-I concentration and ultrasound measurements of backfat thickness and longissimus muscle area in Angus beef cattle J Anim Sci, September 1, 2003; 81(9): 2164 - 2170. [Abstract] [Full Text] [PDF]

				A. M. Stelzleni, T. L. Perkins, A. H. Brown Jr., F. W. Pohlman, Z. B. Johnson, and B. A. Sandelin Genetic parameter estimates of yearling live animal ultrasonic measurements in Brangus cattle J Anim Sci, December 1, 2002; 80(12): 3150 - 3153. [Abstract] [Full Text] [PDF]