To develop a feeding program to fatten heifers, 30 Hanwoo heifers (223±30.7 kg of BW, 8±1.12 months old) were equally distributed into three groups by randomized block design and fed total mixed ration (TMR) for Hanwoo steer in the growing stage (CP 13.65%, TDN 72.7% in DM). Three groups differed in feeding regimen during the growing and fattening stages. Group 1 was fed ad libitum group (ad-lib). Groups 2 and 3 were fed restricted feeding equal to 1.6% (BW1.6) and 1.5% (BW1.5) of body weight per day from 8 to 24 months of age. Heifers in the restricted groups then received the TMR ad libitum from 24 months to slaughtering age (32 months). Although average body gain (0.58 – 0.64 kg/d) and feed intake (7.78 – 9.05 kg/d) were significantly greater (p<0.05) in the ad libitum group than in the restricted groups, there was no difference in the market body weight (685 - 702 kg). Heifers’ carcass weight and ribeye areas were average 407±41.60 kg and 99.9±6.26 cm2, respectively. The cooking loss increased with higher moisture and lower water holding capacity in meat (p<0.05). Amino acid contents of the longissimus muscle were higher in the order of glutamic acid>aspartic acid>lysine>leucine. Oleic acid in the longissimus muscle represented 55.9 - 58.7% of total fatty acids and was higher (p<0.05) in the ad libitum group than in the restricted groups. We concluded that feeding a TMR for steers in the growing stage ad libitum during the entire fattening period, including the growing stage could benefit a Hanwoo heifer fattening program.

본 연구는 한우 암송아지 비육프로그램 개발을 위하여 약 8개월령 30두(평균 체중 233kg)에게 전 시험기간동안 한우 거세우 육성용 사료(CP 13.65%, TDN 72.7% 건물기 준)를 자유채식 또는, 제한급여(체중의 1.5%, 1.6%/일)를 시킨 후, 24개월령부터 출하 시(32개월령)까지는 자유 채 식시켰다. 본 시험에서 출하 시 체중은 685-702kg 이었으 며, 전 기간 평균 사료 섭취량(7.78–9.05kg/일)과 증체량 (0.58–0.64kg/일)은 자유채식구가 제한급여구보다 많았다 (p<0.05). 한우 미경산 암소의 배최장근 단면적은 평균 99.9cm2였으며, 도체중은 평균 407kg이었다. 조리 감량은 수분함량이 높고 보수력이 낮을수록 많았다(p<0.05). 등심 중 아미노산 함량은 glutamic acid, aspartic acid, lysine, leucine 순으로 높았으며, 지방산 중에는 oleic acid가 55.9 –58.7% 수준으로 자유채식구가 제한급여구보다 높았다 (p<0.05). 따라서 한우암소 비육 프로그램으로서, 한우 거세우 육 성용 TMR을 전 기간(6-32개월령) 동안 자유 채식시키면, 사료효율, 도체 성적 및 등심의 물리·화학적 특성에 있어 서도 우수한 결과를 나타낼 수 있을 것으로 판단된다.