This study was conducted to determine the effect of dietary whole-crop barley silage on the daily feed intake, daily weight gain, velvet antler yield and economic efficacy in elk during growth. A total of 21 elk (average BW 303 kg, 5 years old) were allotted randomly to three treatments. The three treatments were T1 (hay diet), T2 (whole-crop barley silage), and T3 (50% hay + 50% whole-crop barley silage). The average daily weight gain of T3 was higher than the others throughout the entire experimental period. The average daily feed intake of elk in decreasing order was as follows; T1>T3>T2. The velvet antler yield was higher in T3 group (8,585 g) compared with T1 (8,037 g) and T2 (7,713 g). However, there were no significant differences in the average daily feed intake, average daily weight gain, or velvet antler yield (p>0.05). In economic efficacy, T3 was gained about 29~43% more value than T1 or T2. In conclusion, the mixed feeding of 50% hay and 50% whole-crop barley silage was more effective than feeding hay of barley alone, in terms of average daily weight gain, velvet antler yield, and economic efficacy in elk.