Two feeding trials were conducted to determine the effects of ration protein level and diethylstilbestrol (DES) implants on Holstein bulls and steers from 14 weeks of age to slaughter (12 to 13 months). Forty-eight bulls and 24 steers in trial 1 and 80 bulls in trial 2 were fed a 90% concentrate ration. Daily gain and feed efficiency were not improved by crude protein levels 2 percentage units higher than the N.R.C. 1970 recommendations for steers and heifers. The 10% crude protein ration depressed daily gain (P<.01) when fed to young bulls between 330-lb (150-kg) and 715-lb (325-kg) live weight. From 715 lb (325 kg) to slaughter at 976 lb (444 kg), there was no influence on gain or carcass traits from rations 1 to 2 percentage units below N.R.C. standards. Daily gains were not improved in bulls implanted with DES. DES implanted bulls had fatter carcasses in both trials, but DES had no effect (P>.05) on marbling score or carcass grade. The overall organoleptic score for rib steaks from bulls in trial 1 was 5.7 where 9.0 represented the most desirable value.
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Williams et al. (1975) studied this question.