###### Abstract  
This study aimed to analyze the effects of whole-crop barley silage (WCBS) and a high-concentrate diet combination to replace a rice straw/concentrate on growth performance, and meat quality of Hanwoo steers (HS). Twenty-four animals were allocated to two groups with a rice straw/concentrate control treatment (CON) and a WCBS/concentrate treatment group. The concentrate was offered to all animals based on live weight after a feeding trial of grass-based diets. Feed intake of WCBS was lower than the CON (\(p<0.01\)) and intake of concentrate was lower in the WCBS group than the CON in all experimental phases (\(p<0.01\)). WCBS increased backfat thickness (BFT) and slaughter weight (p \(>0.05\)). The marbling score was slightly higher in the WCBS group (\(p>0.05\)). WCBS-fed beef had higher crude fat, lower crude protein, and moisture contents. WCBS feeding increased the levels of alpha-linolenic acid (\(p<0.01\)) and decreased arachidonic acid in meat (\(p<0.02\)). Hanwoo steers fed WCBS/concentrate improved feed intake, carcass traits, meat price, palatability, and FA content compared to those fed rice straw/concentrate, suggesting that WCBS is a potential source for improving the growth performance and meat quality in Hanwoo steers with significant economic efficiency. hanwoo steers; whole crop silage; growth performance; carcass quality; fatty acids; economic efficiency +
Footnote †: journal: Applied  
been used to accomplish fattening of cattle in Korea, although the feed can cause excessive decreases in ruminal pH in the late fattening period [4]. Grain crops, such as maize, in agricultural markets for food and feed are increasingly being shifted to the energy market; therefore, estimates of international grain prices are increased by competition for biomass as bioenergy [5]. Therefore, the replacements for grain-based feeds with other type of sources, such as grass, need to be studied. Grass and grass-based grains are essential for ruminants and are low-cost, natural feeds that provide high-quality roughage [6; 7]. Furthermore, feeding grass results in an abundant lipid profile including PUFA, saturated FA (SFA), and conjugated linoleic acid (CLA) [8]. Beef quality, in particular, is largely related to the fat content and FA composition, and animal nutrition is a major factor influencing the FA composition of muscle [1]. High consumer demand in commercial areas requires Hanwoo (_Bos taurus coreanae_) steers to be fatened for slaughter in South Korea. In general, the skeletal muscle of beef is not only a protein source, but also contains appreciable quantities of polyunsaturated FA (PUFA), such as alpha linolenic acid (C18:3 n-3), linoleic acid (C18:2 n-6), and oleic acid (C18:1 n-9), which confer beneficial effects on consumer health [9]. Thus, meat production processes, to satisfy retailer and consumer demands, should attempt to include grass-enriched beef production systems, which must still meet quality expectations of consumers in terms of food quality [10]. However, it has been reported that fat from grass-finished beef may have a yellowish appearance from an elevated carotenoid content, indicating that grass-rich diets might produce negative effects on meat quality [8]. It has been shown that increasing the proportion of concentrate in forage-based diets for fattening ruminants can improve meat production efficiency [11]. In addition, the efficiency of utilization of absorbed nutrients for the synthesis of animal tissues or products is usually increased when concentrate is incorporated into a forage diet [12]. Furthermore, an appropriate combination of concentrate and forage in the diet optimizes the fattening of ruminants and results in a more rapid and efficient growth and heavier carcasses than by the intake of concentrate or forage alone [13]. Inclusion of fresh forage in the diet for lactating buffalo showed an increment of unsaturated fatty acids and reduced short-chain fatty acid percentage.