Relationships of Hip Height Measurements with Growth and Carcass Traits of Crossbred and Angus Cattle

Hip heights were measured on 286 three-breed cross calves at weaning, yearling and slaughter time and on 199 Angus calves at yearling time to study the relationships of hip height with growth, feedlot performance and carcass traits when cattle are slaughtered at an anticipated grade of low choice. Correlations between hip height and weaning, yearling and slaughter weight averaged .56. Yearling hip height (YHT) was more closely associated with feedlot ADG in crossbred cattle than was weaning hip height (WHT), .29 vs .14. The correlation of YHT with feedlot ADG was higher in Angus (.46). Hip height at slaughter (SHT) was not associated with rate of gain in the feedlot (r= .02). The correlations for Angus YHT with slaughter age and days on feed ( .32 and .33) suggested taller Angus cattle at yearling time generally reached low choice with fewer days in the feedlot and were thus younger at slaughter. This relationship was not nearly as strong in the crossbred cattle (respective correlations of .04 and .05). Correlations of hip heights with carcass traits were generally low with a tendency for correlations to be higher in Angus cattle. Hip height was more highly correlated with carcass weight-per-day (averaged .31) than for other carcass traits. Prediction equations were developed for feedlot ADG, days on feed, slaughter weight and rib eye area based on weight and hip height measurements. Comparisons among prediction equations were based on comparing coefficients of determination (R 2) which indicate the proportion of the variation in the predicted trait that is accounted for by the respective prediction equations. On average of crossbred and Angus groups, the order of pr;edictability was slaughter weight (R 2=.78), feedlot ADG (R2 = .66), days on feed (R2 =.41) and rib eye area (R2 =.23). In general, weight was a more reliable predictor that hip height and combining hip height with weight yielded little practical improvement in predictability.