시험 1. 농후사료 섭취수준이 한우 번식우의 성장, 체형형질, 도체특성, 혈액성상 및 번식성적에 미치는 영향
본 연구는 한우 번식우의 효율적인 사양조건 설정을 위한 기초자료를 확보하기 위하여 14개월령 한우 암송아지 18두 (체중 251.4kg)에게 사료섭취량(2 수준)을 달리 하여 34개월령까지 사육하였을 때, 사료효율, 체중 및 체형의 변화를 조사하였다. 처리구는 전 시험기간 동안 농후사료를 체중의 0.8%(T1) 및 1.2%(T2)씩 섭취하는 2 처리구로 나누어 처리구당 한우 암송아지 9두(2 우리)를 각각 완전임의 배치하였다. 체중은 1개월 단위로 측정하여 처리구의 비율대로 농후사료를 조절 급여하였으며, 조사료는 곤포 볏짚을 자유채식 시켰다. 사료 섭취량은 매일 측정하였으며 체형은 2개월 단위로 한국종축개량협회 심사기준에 따라 측정하였다.
전 시험기간 동안 농후사료 섭취량은 T2구가 T1구보다 두당 일일 평균 1.67kg 더 많이 섭취하였으며, 볏짚 섭취량은 차이가 없었다. 34개월령 공시축의 체중 및 일당증체량은 T1구보다 T2구가 각각 30%, 57%나 유의적으로 높게 나타났다(p＜0.01).
한우사양표준(2007) 암소 육성에 필요한 영양소요구량(체중 250～300kg, 일당증체량 0.2kg 기준)과 비교 시, T1구 (14～24개월령)에서 TDN과 조단백질 섭취량이 각각 12～42% 및 4～14% 많았지만, 일당증체량은 오히려 7.5% 정도 낮은 수준이었다. 그러나 25～34개월령에서는 동 기준의 한우사양표준과 비슷한 수준으로 나타났다. 한편 T2의 경우, 한우사양표준(2007) 동 기준과 비교했을 때, TDN 및 조단백질 섭취량은 각각 35～43% 및 37～43% 많았으며, 일당증체량도 53%나 높게 나타났다. 사료요구율은 T1과 T2구에서 각각 33.9 및 17.8 수준인 것으로 나타났다.
체형은 15개월령에서는 처리간 비슷한 수준이었으나, 34개월령에서는 T1이 T2구보다 체장은 10.0cm, 체고는 1.0cm, 십자부고는 6.6cm, 흉심은 4.6cm, 흉폭은 9.4cm, 흉위는 20.6cm 작은 것으로 나타났다. 그러나 한국종축개량협회에서 제시한 한우 암소발육표준(34개월령)과 비교하였을 때, T1구에서 흉폭은 12.7%나 낮은 반면, 체장, 체고, 십자부고, 흉심 및 흉위는 비슷한 수준이었다. 체위증가율에서 T1구는 체장, 체고, 십자부고, 흉심 및 흉위는 정상적으로 증가하였으나 흉폭은 34개월령이 15개월령보다 오히려 3.78% 줄어드는 현상을 나타내었다. T2구에서는 월령이 증가함에 따라 조사된 체위가 9.8%～23.5%까지 증가하였다. 초음파를 이용한 도체형질 예상치에서 T2가 T1에 비해 도체중은 115kg, 배최장근단면적은 20.94㎠나 큰 것으로 나타났다(P＜0.01). 체충실지수와 난소의 크기는 T2구가 T1에 비해 유의적으로 높았으나(P<0.05) 혈중 NEFA, glucose, BUN 함량은 처리간에 유의적인 차이를 보이지 않았다. 임신율은 T1이 43%, T2가 78%였으며, 분만율은 각각 22.2% 및 66.7%였다. 분만한 송아지의 평균 생시체중은 T2가 T1구보다 7kg 많았다.
본 시험의 결과를 종합해 보면, 한우 번식우에 있어서 농후사료 섭취수준을 체중의 0.8%로 급여하였을 때, 한우사양표준 암소 육성에 필요한 영양소요구량과 비교하였을 때, 건물섭취량과 TDN섭취량이 높았으나 일당증체량은 오히려 낮았으며, 농후사료를 체중의 1.2%수준으로 급여하였을 때 비슷한 일당증체량 기준과 비교하여 건물섭취량과 TDN섭취량이 낮은 것으로 나타났다. 번식성적에 있어서도 흉폭을 제외한 대부분의 체형이 정상적이었던 농후사료 0.8%급여구는 번식률과 난포발육이 부진한 반면, 농후사료 1.2%급여구에서는 번식우로서 비만한 편이었으나 임신율과 분만율이 좋은 편이었다. 따라서 본 시험의 성적은 한우사양표준 번식우 부분의 새로운 자료로서 활용될 수 있을 것으로 사료된다.

시험 2. 사료의 급여형태가 한우 거세우의 사료효율, 도체성적, 배최장근의 이화학적 특성 및 혈액성상에 미치는 영향
본 연구는 TMR 시스템에 의한 한우 고급육 생산 프로그램에서 문제가 되고 있는 비육후기용 TMR 사료개발을 위하여 시중에서 유통되고 있는 TMR급여구(TMR구)와 농ㆍ조 분리급여구(관행구), 그리고 비육후기에 TMR에 농후사료를 추가 급여(1.0～1.5kg/일)한 혼합구(혼합급여구)로 나누어 사양성적, 혈액성상, 도체성적, 육(肉) 조직의 이화학적 특성 및 경제성 분석을 실시하였다. 한우 거세우 60두(평균 8.1개월령, 평균체중 224.7kg)를 각 처리구당 20두(4 우리)를 배치하여 총 22개월간의 사양시험을 수행하는 동안, 물과 미네랄블록은 자유섭취토록 하였다.
한우 거세우의 건물섭취량은 전체적으로 22개월령부터 감소하는 경향을 보였으며, TMR구에서는 16개월령부터 건물섭취량이 떨어지기 시작하였다. TMR사료의 비육후기 사료섭취량 저하를 막기 위해 첨가한 농후사료(혼합구)에 의해 일일 건물섭취량이 약 10kg (29～30개월령)까지 회복되었다.
일당증체량은 관행구와 혼합구가 각각 일일 평균 0.75kg 및 0.73kg이었으며, TMR구에서는 0.67kg으로 가장 낮았다(P＜0.05).
혈 중 retinol함량은 16개월령에서 혼합구가 다른 처리구에 비해 유의적으로 낮았으나(P<0.05), 혈 중 leptin 함량은 처리간 유의적인 차이가 없었다. 혈 중 insulin 함량은 전 처리구에서 21개월령과 28개월령에 다른 월령에 비해 유의적으로 높게 나타났다(P＜0.05). 혈액의 생화학성분 중 AST는 관행구가 TMR구와 혼합구보다 유의적으로 낮게 나타났으며(P＜0.05), BUN의 함량은 28개월령과 30개월령에 TMR구가 관행구와 혼합구보다 낮게 나타났다(P＜0.05). 혈중 cholesterol과 triglyceride 함량은 관행구가 TMR구와 혼합구보다 높았다(P＜0.05).
배최장근의 총 필수아미노산 함량은 혼합구가 가장 높았고, 아미노산 중 가장 높은 비율을 차지한 glutamic acid는 혼합구가 관행구보다 높았다(P＜0.05). 근내지방 중 oleic acid 함량은 TMR구와 관행구가 혼합구보다 높았다(P＜0.05).
배최장근의 보수력(WHC, %)과 가열감량(CL, %)은 관행구가 TMR구와 혼합구보다 높았으며(P＜0.05), 관능검사에서 풍미는 관행구, TMR구, 혼합구 순으로 좋은 것으로 나타났다(P＜0.05). 도체중은 생체중이 낮았던 TMR구가 관행구와 혼합구보다 낮게 나타났으며(P＜0.05), 등심단면적은 TMR구가 가장 낮았다(P＜0.05). 등지방 두께와 근내지방도는 처리간 차이가 없었으며, 육질등급 1++의 등급은 관행구에서 25%로서 가장 높았다.
혈중 retinol함량은 도체중과 성숙도와 각각 부(-)의 상관관계(P<0.05)를 가졌으며, insulin은 등지방두께와 정(+)의 상관관계(P<0.05)를, 근내지방도는 BUN과 정(+)의 상관관계(P<0.05)를 나타내었다. Albumin은 등심단면적과 육량등급과는 부(-)의 상관관계(P<0.05)를 보였다. 도체중은 myristic acid와 magaroleic acid와는 각각 높은 정(+)의 상관관계(r=0.7780＊＊, r=0.7801＊＊)를, stearic acid와는 부(-)의 상관관계(r=-0.7773＊＊)를 나타내었다. 등지방두께는 pentadecanoic acid(C15:0)와 부(-)의 상관관계(r=-0.5862＊)를 보였으며, 등심단면적은 stearic acid와는 부(-)의 상관관계(r=-0.7100＊＊)를 보였다. 배최장근의 myristic acid는 magaroleic acid와는 정(+)의 상관관계(r=0.9339＊＊)를, stearic acid(C18:0)와는 부(-)의 상관관계(r=-0.8699＊＊)를 나타내었다. 근내지방의 palmitic acid는 oleic acid (r=-0.6935＊)와 linoleic acid (r=-0.8558＊＊)와 각각 부(-)의 상관관계를 보였다.
배최장근의 관능특성과 지방산 함량과의 상관관계를 보면, butyric acid는 풍미와 연도와 부(-)의 상관관계(r=-0.9695＊＊, r=-0.89683＊)를 보였으며, stearic acid(C18:0)는 풍미와 다즙성과 부(-)의 상관관계(r=-0.6389＊＊, r=-0.5753＊)를 나타내었다. Oleic acid는 풍미와 다즙성과 정(+)의 상관관계(r=0.6142＊,r=0.5707＊)를 보였다.
경제성 분석에서 조수익은 TMR구가 혼합구에 비해 약 10%나 낮았으나, 경영비는 사료비의 절감으로 인해 TMR구가 관행구에 비해 약 4.3% 적었다. 수익성은 TMR구 가장 저조하였고, 혼합구에서 가장 좋은 것으로 나타났다.
결론적으로 한우 거세우의 TMR사양체계에서 비육후기에는 TMR에 농후사료를 추가 급여하는 것이 적합한 것으로 사료된다.

Experiment 1. Effect of feeding levels of concentrates on growing performance, blood composition and reproduction in Hanwoo heifers
Eighteen Hanwoo heifers averaging 251.4kg of body weight (14 month of age) were used to investigate feed efficiency, body weight gain, body size and reproductive rate according to the feeding levels of concentrate, and were alloted to two treatments by a completely randomized design. Treatments were composed of heifers fed concentrates of 0.8%(T1) and 1.2%(T2) of body weight during the whole experimental period (34 month of age), respectively, Body weight, feed intake and body size were measured monthly, daily and bimonthly, respectively. Heifers could freely accessed to rice straw, water and mineral block during the whole experimental period.
The amount of concentrate intake was greater in T1 which took more average 1.67kg per day during the whole experimental period, and rice straw intake did not differ between two treatments. Body weight and daily body gain of heifers in 34 months of age were significantly (P<0.01) greater by 30% and 57% in T2 compared to T1, respectively. Comparing to the nutrient requirements (weight 250～300kg, daily weight gain 0.2kg) of Korean Feeding Standard for Hanwoo cow(2007), even though TDN and crude protein intakes in T1 were greater during the whole experimental period (14 to 24 months of age) from 12% to 42% and 4 to 14% each, although daily body weight gain was rather lower by approximately 7.5%. During 25 to 34 months of age, however, TDN and crude protein intakes were similar to the specifications of the Feeding Standard for Hanwoo cow. Meanwhile, TDN and crude protein intakes in T2 were greater from 35 to 43% and 37 to 43%, respectively, and daily body gain in T2 was 53% higher compared to the nutrient requirements (body weight 250～300kg, daily body gain 0.2kg) of Korean Feeding Standard for Hanwoo(2007). Feed conversion, feed requirement for 1kg of body gain, was 33.9 for T1 and 17.8 for T2. Body size of T1 comparing to T2 was 10.0cm smaller for body length, 1.0cm for withers height, 6.6cm for hip height, 4.6cm for chest depth, 9.4cm for chest width, 20.6cm for chest girth in 34 months of age. Body sizes in T1 were similar levels with those of Hanwoo cows developed standard (34 month old) which was presented in Korean Animal Improvement Association, besides, chest width decreased by 12.8%. Furthermore, chest width of 34 month of age in T1 was rather decreased by 3.78% compared to that of 15 month of age, on the other hand, body length, withers height, hip height, chest depth and chest girth increased normally. All the body sizes in T2 increased from 9.8 to 23.5% with increasing the month of age. From the carcass characteristics estimated by ultrasonic analysis, T2 were significantly(P<0.01) greater 115kg for carcass weight, 20.94 ㎠ for longissimus dorsi area compared to T1. Body condition score and ovary size were significantly (P<0.05) higher in T2 compared to T1. Concentrations of plasma NEFA, glucose and BUN did not show significant differences between treatments.
T1 had very low pregnancy rate (43% vs 78%), birth rate(22.2% vs 66.7%) and average birth weight of calf (22.5kg vs 29.5kg) compared to those of T2.
In summary, when T1, Hanwoo cows were fed concentrates as much as 0.8% of body weight, was compared with the nutrient requirements in Korean Feeding Standard for Korean cow(KFSc), even though intakes of dry matter and TDN were greater in T1, but daily body gain was rather lower than that of the KFSc (based on 0.2kg of daily body gain). Meanwhile, T2 group which was fed as much as 1.2% of body weight showed was lower in the intakes of dry matter and TDN compared to the KFSc (based on 0.4kg of daily body gain). The chest width of 34 month of age in T1 was rather smaller compared to that of 15 month of age, even though other body sizes were increased normally. T1 group which was fed as much as 0.8% of body weight showed poor reproduction and follicle growth. Whereas Hanwoo cows, which was fed as much as 1.2% of body weight, had good pregnancy and delivery rates. Thus, the data of this experiment could be applied to the Korean Feeding Standard for Korean Cattle (Cows).

Experiment 2. Effect of dietary feeding type on growing performance, blood composition and carcass traits in Hanwoo steers
This experiment was conducted to develop the TMR for Hanwoo during the late fattening phase in the feeding program for production of high quality meat, During the experiments, growing performance, blood composition, carcass characteristics, chemical composition of longissimus dorsi muscle and economical analysis were investigated. Treatments were composed of the commercial formula feed(FF), TMR and TMR plus concentrate(MIX, 1.0～1.5kg/day) during late fattening phase. Sixty Hanwoo steers averaging 225 kg (8 month of age) were alloted equally(20 steers, 4 pens) to three treatments by a completely randomized design. During 22 months of feeding trial, body weight and feed intake were measured monthly and daily, respectively and blood was collected through jugular vein according to growing and fattening stage. Steers could freely access to water and mineral block.
Dry matter intake showed the tendency to decrease after 22 months of age in Hanwoo steers, and reduced from 16 months of age in TMR. Dry matter intake of the MIX were recovered to 10kg per day(29～30 months of age) by concentrates supplemented to prevent a decrease of TMR intake during late fattening phase.
Daily body gain was average 0.75kg and 0.73kg in FF and the MIX, respectively, and was the lowest(P<0.05) as 0.67kg in TMR.
Plasma retinol concentration at the 16 month of age was significantly lower(P<0.05) in MIX compare to other treatments. There were not significant differences among treatments in plasma leptin concentrations, but insulin level was higher(P<0.05) in 21 month and 28 month of ages compared to other ages in all treaments. Of the biochemical constituents of blood, AST was significantly(P<0.05) lower in the FF than TMR and MIX, and BUN was significantly(P<0.05) lower in TMR than FF feed and MIX on 28 and 30 months of age. Plasma cholesterol and triglyceride contents were higher(P<0.05) in FF feed than TMR and MIX. Total essential amino acid content of longissimus dorsi muscle was highest in MIX, the content of glutamic acid that accounted for the highest of amino acid were higher in MIX than the FF(P<0.05).
Oleic acid content of intramuscular fat was higher in steers fed the FF or TMR than MIX(P<0.05).
Water holding capacity and cooking loss of longissimus dorsi muscle were higher(P<0.05) in the FF than the TMR and MIX, The flavor from sensory evaluation practices was higher(P<0.05) in the order of the FF, TMR and MIX.
The carcass weight was lower in steers fed TMR than the FF or MIX, and longissimus dorsi muscle area was the smallest(P<0.05) in TMR. There were no significant difference in back fat thickness and marbling score between treatments, however the meat quality grade of 1++ was the highest as 25% in steers fed FF.
The plasma retinol content showed a negative(-) correlation(P<0.05) with carcass weight and maturity, the plasma insulin level had a positive (+) correlation(P<0.05) with back fat thickness, and the marbling score showed a positive correlation(P<0.05) with BUN. Albumin showed the negative (-) correlation(P<0.05) with longissimus dorsi muscle area and yield grade, respectively. The carcass weight showed a positive(+) correlation with a myristic acid(r=0.7780**) and magaroleic acid(r=0.7801**), and showed the negative (-) correlation(r=-0.7773**) with stearic acid of intramusculr fat. The back fat thickness showed a negative (-) correlation(r=-0.5862*) with pentadecenoic acid, and showed a negative (-) correlation(r=-0.7100**) with stearic acid of intramusculr fat. Myristic acid of intramusculr fat showed a positive(+) correlation(r=0.9339**) with magaroleic acid, and showed a negative(-) correlation(r=-0.8699**) with stearic acid. Palmitic acid showed each negative(-) correlation with oleic acid(r=-0.6935*) and linoleic acid(r=-0.8558**), respectively. In the correlation between fatty acid content and sensory characteristics of longissimus dorsi muscle, butyric acid showed a negative (-) correlation with flavor(r=-0.9695**), softness(r=-0.89683*), and stearic acid showed a negative (-) correlation with flavor(r=-0.6389*) and juiciness(r=-0.5753**). Oleic acid showed a positive (+) correlation with flavor(r = 0.6142*) and juiciness(r=0.5707*), respectively.
In the economical analysis, crude income was approximately about 10% lower in the TMR than MIX, but operating cost of the TMR was about 4.3% lower compared to the FF due to feed cost. Finally profitability was highest in MIX and lowest in TMR.
Overall, supplementation of an adequate amount of concentrate to TMR was required for Hanwoo steers in late fattening phase.