Abstract: The objective of this study was to evaluate commercial feedlot growth performance factors that contribute to the variation in DP of bulls and heifers. Feedlot growth-performance data involving 878 pens of bulls and 784 pens of heifers were used to develop models for predicting Dressing Percentage (DP, 100* hot carcass weight/ final slaughter weight). Dressing percentage was similar for bulls and heifers, averaging 61.7?0.9%. Final Slaughter Weight (FSW, kg) explained 92% of the variation in Empty Body Weight (EBW, kg=15.941+0.877FSW; r =0.921) and 89% of the variation in hot carcass weight (HCW, kg=27.827+0.554FSW; r = 0.893). However, FSW, alone, explained much less (r = 0.10) of the variation in DP. Digestive tract fill averaged 11.4% with a range of 7.8 to 15.6%. Dressing percentage of bulls and heifers was inversely associated with DMI (DP = 68.061 -.874 DMI, kg; r = 0.32). Initial weight of cattle when entering the feedlot (IW, kg) was a better single predictor of DP than DMI, explaining 46% of the variation. However, IW was also a good predictor of DMI (r = 0.66): DMI = 4.6346 +.01422 IW. Based on stepwise regression analysis, factors that best described variation in DP were IW, FSW and DMI: DP =62.277-0.0131 IW+ 0.00920 FSW-0.212 DMI (r = 0.49). However, because of the close association between IW and DMI (lack 2 of independence), the contribution of DMI to the prediction was small. Removing DMI from the equation, the model becomes: DP = 61.857-0.148 IW + 0.00759 FSW (r = 0.48). We conclude that the effect of gender on DP 2 is small and nonappreciable. Initial weight and FSW are useful linear predictors of DP, explaining 48% of the variation. Dressing percentage decreases with increasing IW. For a given IW, DP increases with increasing FSW.
N.Torrentera and R.A Zinn , 2005. Predicting Carcass Dressing Percentage in Feedlot Bulls and Heifers . Journal of Animal and Veterinary Advances, 4: 659-662.