|Van Vleck, Lloyd|
Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/30/1997
Publication Date: N/A
Interpretive Summary: Some beef producers need to compare bulls of different breeds to use in their herds to produce commercial calves. Most breed associations publish genetic evaluations but these can be used only to compare bulls of the same breed. Eight breeds of sire were compared from their progeny records for birth, weaning, and yearling weight at five state experiment stations cooperating in project NC-196. The breed differences were adjusted to a base year of birth using the within-breed genetic evaluations of bulls born in the base year and of bulls used in the NC-196 project. These adjustments allow calculation of factors to add to within-breed genetic evaluations to allow comparison of bulls across-breeds. The factors calculated from NC-196 project were similar to those calculated previously from records produced at the Meat Animal Research Center for those breeds of sire. The results also indicated that on average differences for NC-196 6bulls predicted by within-breed genetic evaluations were reflected at the NC-196 stations in birth and weaning weights of their progeny but only 62% of the expected progeny differences in yearling weight were reflected in the four breeds and at the two stations with yearling weight records.
Technical Abstract: Records on growth traits were obtained from five Midwestern agricultural experiment stations as part of a beef cattle crossbreeding project (NC-196) Records on birth weight (BWT, n = 3,490), weaning weight (WWT, n = 3,237), and yearling weight (YWT, n = 1,372) were analyzed within and across locations to obtain estimates of breed of sire differences and heritabilities. Solutions for breed of sire differences were calculated and adjusted to a common base year, then factors to use with within-breed EPD to obtain across-breed EPD were calculated. These factors were compared with factors obtained from similar analyses of records from the U.S. Meat Animal Research Center (MARC). Progeny of Brahman sires mated to Bos taurus cows were heaviest at birth and among the lightest at weaning. Simmental and Gelbvieh sires produced heaviest progeny at weaning. Estimates of heritability pooled across NC-196 locations were .34, .19, and d.07, for BWT, WWT, and YWT, respectively. Regression coefficients of progeny performance on EPD of sire were 1.25 plus/minus .09, .98 plus/minus .13, and .62 plus/minus .18 for BWT, WWT, and YWT, respectively. Rankings of breeds of sire generally did not change when adjusted for sire sampling. Rankings were generally similar to those previously reported based on MARC data, except for Limousin and Charolais sires which ranked lower for BWT and WWT at NC-196 locations than at MARC. Adjustment factors used to obtain across-breed EPD were largest for Brahman for BWT and for Gelbviveh for WWT and YWT.