INTRODUCTION
The use of technology in the feedlot industry such
as β-adrenergic agonists (βAA) has increased in recent
years. Zilpaterol hydrochloride (ZH) has been reported
to increase ADG, G:F, HCW, carcass yield grade, and
dressing percentage in finishing cattle (Vasconcelos
et al., 2008). Binding of ZH to a β-adrenergic receptor
causes an increase in muscle hypertrophy through
changes in protein synthesis and degradation rates.
Feeding ZH has been reported to increase final BW by
9 kg and increase HCW by an average of 15 kg in steers
(Delmore et al., 2010). Furthermore, the effect of ZH on
HCW is accentuated by a simultaneous increase in dressing
percentage typically ranging from 1.5 and 2.0% (Delmore
et al., 2010). Additionally, yield grade is reduced and LM
area is increased by 14%, whereas marbling score and
USDA quality grade have been reported to decrease with
feeding ZH. However, there is an absence of data in the
literature on the effects of ZH with and without coproducts
such as wet distillers grains with solubles (WDGS).