Journal of Animal Science, Vol 78, Issue 2 275-282, Copyright © 2000 by American Society of Animal Science

JOURNAL ARTICLE

Comparison of models for genetic evaluation of scrotal circumference in crossbred bulls

P. B. Mwansa, R. A. Kemp, D. H. Crews Jr, J. P. Kastelic, D. R. Bailey and G. H. Coulter
Lethbridge Research Centre, Agriculture and Agri-Food Canada, Alberta.

The aim of this study was to evaluate the effect of including concomitant body weight and(or) a random dam effect in genetic evaluation models on variance component estimates and standard error of prediction for scrotal circumference (SC) at 6, 8, 10, and 12 mo. Variance components and average standard errors of prediction were compared under models differing in either the number of related traits (M11 [SC], M12 [SC and BW]) or an uncorrelated random dam effect (M21 [SC], M22 [SC and BW]) using records on 1,547 bull calves. In a single-trait model (M11), estimates of direct heritabilities (h2a) for SC were .45, .49, .57, and .66 at 6, 8, 10, and 12 mo, respectively. In a two-trait model (M12), h2a were similar to those in M11 model. In M21, h2a for SC were .37, .42, .54, and .65, whereas the proportions of phenotypic variance due to dams (d2) were .12, .11, .04, and .02 at 6, 8, 10, and 12 mo, respectively. Similarly, in M22, h2a for SC were .36, .44, .56, and .65 and d2 were .13, .10, .02, and .02. Standard errors of prediction for SC EBV from M22 were reduced by 2.86, 1.21, 3.02, and 1.99% relative to M21 and by 6.45, 2.70, 2.72, and 1.21% relative to M11 at 6, 8, 10, and 12 mo, respectively. Standard errors of prediction for SC EBV from M12 were reduced by .06, .73, 1.56, and .87% relative to M11 at 6, 8, 10, and 12 mo, respectively. The importance of the dam effect decreased with age for both SC and BW. These results demonstrate that a two-trait (SC and BW) animal model would result in more accurate evaluations of yearling SC EBV in beef cattle than a single-trait model.

This article has been cited by other articles:

				M. H. Gillis, S. K. Duckett, and J. R. Sackmann Effects of supplemental rumen-protected conjugated linoleic acid or corn oil on lipid content and palatability in beef cattle J Anim Sci, June 1, 2007; 85(6): 1504 - 1510. [Abstract] [Full Text] [PDF]

				A. N. Hristov, K. L. Grandeen, J. K. Ropp, and M. A. McGuire Effect of Sodium Laurate on Ruminal Fermentation and Utilization of Ruminal Ammonia Nitrogen for Milk Protein Synthesis in Dairy Cows J Dairy Sci, June 1, 2004; 87(6): 1820 - 1831. [Abstract] [Full Text] [PDF]

				M. H. Gillis, S. K. Duckett, and J. R. Sackmann Effects of supplemental rumen-protected conjugated linoleic acid or corn oil on fatty acid composition of adipose tissues in beef cattle J Anim Sci, May 1, 2004; 82(5): 1419 - 1427. [Abstract] [Full Text] [PDF]

				M. H. Gillis, S. K. Duckett, J. R. Sackmann, C. E. Realini, D. H. Keisler, and T. D. Pringle Effects of supplemental rumen-protected conjugated linoleic acid or linoleic acid on feedlot performance, carcass quality, and leptin concentrations in beef cattle J Anim Sci, March 1, 2004; 82(3): 851 - 859. [Abstract] [Full Text] [PDF]

				D. H. Crews Jr., N. H. Shannon, R. E. Crews, and R. A. Kemp Weaning, yearling, and preharvest ultrasound measures of fat andmuscle area in steers, bulls, and heifers J Anim Sci, November 1, 2002; 80(11): 2817 - 2824. [Abstract] [Full Text] [PDF]

				D. H. Crews Jr. and R. A. Kemp Genetic evaluation of carcass yield using ultrasound measures on young replacement beef cattle J Anim Sci, July 1, 2002; 80(7): 1809 - 1818. [Abstract] [Full Text] [PDF]