본 실험은 Holstein 비육후기에 홍삼박, 광물질 및 설탕을 첨 가 급여하여 건물채식량, 일당증체량, 육질특성 및 경제성에 미치는 영향을 조사하고자 수행하였다. 시험구는 4처리로서 홍삼박, 광물질 및 흑설탕을 급여하지 않는 처리구를 대조구(C), 홍삼박 200g 첨가 급여 구는 T1, 홍삼박 100g과 광물질 50g 첨가 급여구는 T2 그리고 광물질 50g과 흑설탕 20g 첨가 급여한 구를 T3 로 나누어 실시하였다. 그리고 본 실험에서 얻어진 결과를 요약해 보면 다음과 같다. 총 사료섭취량 및 1일 채식량은 T2 및 T3구가 C구에 비하여 유의적으로 높게 나타났다(p<0.05). 또한 채식량 이 많았던 T2 및 T3구에서 총 증체량 및 일당 증체량이 높게 나 타났지만 유의적인 차이는 없었다. 사료 요구율은 C구가 다른 구 (T1, T2, T3)에 비하여 유의적으로 높게 나타났지만(p<0.05), T1, T2 및 T3 구간에는 유의적인 차이가 없었다. 등지방두께, 등심단 면적 및 육량등급은 처리구 상호간 유의적인 차이가 없었다. 근내 지방은 T3(4.5) > T1(4.0) > T2(2.7) > C(2.5)구순으로 높게 나타났다(p<0.05). 그러나 육색, 지방색, 조직감 및 성숙도는 상호 처리 간 유의적인 차이가 없었다. 육질등급은 상호 처리 간 유의적인 차이는 보이지 않았지만 T3 > T1 > T2 > C 순으로 높은 경향을 보였다. 경제적 조수익성은 T3 > T1 > T2 > C구순으로 나타 났다. 이상의 결과를 종합해 볼 때, 배합사료와 조사료 만 급여하는 체계(C) 보다는 홍삼박, 광물질 및 흑설탕을 첨가 급여(T1,T2, T3)하는 체계가 도체등급 및 수익성 증대에 유리하며, 특히 증체량, 육질등급 및 경제성을 고려하였을 때 T3구가 가장 좋은 급여체계로 나타났다.

본 연구는 Holstein 거세 비육우의 성장 단계에 따른 채식 및 반추행동에 미치는 영향을 규명하기 위하여 실시하였다. 실험에 사용한 공시 Holstein 거세우는 육성 단계(T1), 비육전기 단계(T2) 그리고 비육 후기 단계(T3)을 각각 3두씩, 총 9두를 3처리 3반복으로 배치하였다. 사료급여는 농후사료 체중의 1.62%, 조사료는 자유 채식시킨 후 육안으로 48시간 채식 행동관찰을 실시하였다. 체중대비 건물섭취량은 T1구(2.21%) 가장 높게 T3구 (1.39%)가 가장 낮게 나타났다. 채식시간은 T1, 반추시간은 T2 그리고 휴식시간은 T3 구에서 높게 나타났다(p<0.05, 0.01). 저작 시간은 T1 및 T2구에 비하여 T3구가 현저히 떨어지는 것으로 나타났다(p<0.01). 식괴수와 총 저작수는 다른 처리구에 비하여 T2구가 유의적으로 높게 나타났다(p<0.01). 그러나 식괴 당 저작수 및 분 당 식괴수는 T1구가 높게 나타났지만 상호 처리간 유의적인 수준은 나타나지 않았다. 음수 회수 및 배분 회수는 처리 구들 간에 유의적인 차이가 없었다. 그러나 배뇨 회수는 어린 단 계인 T1 구에서 유의적으로 높게 나타났다(p<0.01). 음수 시간, 배분시간, 배뇨시간은 T1 구에서 높게 나타났지만, 개체 차이가 심하여 유의적인 차이는 보이지 않았다. 이상의 결과를 종합하면 비육후기 단계(T3)는 육성(T1) 및 비육전기(T2)비하여 체중대비 채식량이 낮음에 따라 채식시간 반추시간은 줄어들고 휴식시간은 증가하는 것으로 나타났다. 또한 T3구는 총 식괴수 및 총 저작수도 떨어지는 것으로 나타났다.

The present study evaluated the influence of rumen inocula of different breeds on in vitro fermentation with forage and concentrate substrates. An in vitro was conducted under a 2×2 factorial arrangement with two breeds (Jersey and Holstein steers) and two feed substrates (forage and concentrate) as factors. Three Jersey and 3 Holstein steers were used for the source of in vitro inocula. Metataxonomic analysis of donor rumen fluids showed that Firmicutes was more abundant in Jersey, while Bacteroidetes in Holstein steers. In vitro ㏗ was lower in the fermented inocula of Jersey steers and in the concentrate substrate (p<0.05). After 24h, higher gas production, dry matter, and neutral detergent fiber degradability, and total volatile fatty acids concentration were noted in concentrate substrate (p<0.05). After 24h, inocula of Jersey steers had higher methane and ammonia-nitrogen (p<0.05). After 24h, fermented inocula of Holstein steers produced higher propionate (p<0.05). Conversely, in vitro butyrate production was higher in the fermented inocula from Jersey steers (p=0.072) and in those with concentrate substrate (p<0.05). After 24h, the total bacterial population (log10 c opies) was h igher in t he fermented inocula received from Jersey steers and in the concentrate substrate whereas, Fibrobacter succinogenes and Ruminococcus flavefaciens population were higher (p<0.05) only in the concentrate substrate. Overall results suggest that rumen inocula of different donors influence in vitro fermentation either with forage or concentrate substrates.

TMR 급여와 분리급여가 반추위 메탄발생량 변화에 미치는 효과를 연구한 사례가 많지 않다. 본 실험은 1일 실험사료를 체중의 1.8%(실험 1) 그리고 2.4%(실험 2) 수준에서 급여 하면서 triplicated 2×2 Latin square design을 이용하여 실험을 수행하였다. 각 실험에는 6마리의 Holstein steer를 이용하였고 2개의 군으로 나누어 각각 TMR 급여 또는 분리급여를 하였다. 공시 사료의 농후사료와 조사료 비율은 73% 그리고 27%이었다. 두 실험 모두 사료급여 방식 간의 1일 메탄발생량 차이가 없었다. 현재까지 보고된 국내 연구와 본 연구에서 얻어진 개체 별 1일 건물섭취량과 1일 메탄발생량과의 관계를 분석한 결과, 메탄발생량 (g/d) = 11.5 (±1.3) × 건물섭취량 (kg/d) + 14.2, R2 = 0.73, p<0.001의 회귀식을 유도하였다.

The present experiment was designed to investigate the effects of extruded linseed supplementation on methane production in Holstein steers. Four Holstein steers fitted with permanent cannulas were assigned to two dietary treatments in a duplicated 2 × 2 Latin square design: a control diet consisting of tall fescue straw (65%) and concentrate (35%), and a treatment diet supplemented with 3.8% extruded linseed by replacing a part of ingredients in the concentrate of the control diet. The concentrates of the control and the treatment diet were isoenergetic and isonitrogenous. Extruded linseed supplementation did not affect dry matter intake but significantly (P<0.05) increased the intake of lipid. Rumen pH was significantly (P<0.05) lower for control than for treatment. Although there was no significant difference between treatments, the concentration of total VFA in control was 21% higher than in treatment. The concentrations of acetic acid, propionic acid and butyric acid were not different between treatments. Extruded linseed supplementation significantly (P<0.05) reduced methane output(g/d) and emission factor. Methane conversion rate was lower for treatment than for control but no significant difference was found. The results of the present study showed that extruded linseed supplementation in the diet of Holstein steers could reduce methane output.

The objective of this study was to determine how feeding forage and concentrate separately (SF) or as a total mixed ration (TMR) affects enteric methane production of cattle. Six Holstein steers (203 ± 22.5 kg) were used in a 2 × 3 changeover design experiment. Experimental diets (TMR and SF) consisted of compound feed, timothy hay and soybean curd residue in a ratio of 40:48:12, respectively, and diets were fed at 10% of metabolic body weight, on an as-fed basis. There were no differences in dry matter intake and enteric methane production (g/d) between SF and TMR but the methane conversion rate (methane energy/GE intake) of TMR was significantly higher (p=0.05) than that of SF. The mean methane emission factor (kg/head/year) and conversion rate of the two treatments were 21.4 and 0.05, respectively. There was a strong relationship between metabolic body weight and enteric methane production (p<0.001). At the present time, further studies may be necessary in order to establish the effects of TMR and SF on enteric methane production.

This study was conducted to investigate the effects of the slaughtering age on carcass characteristics and economic efficiency of Holstein steers. The Holstein steers (n=27, 4 months old, average body weight 160 ㎏) were divided into 3 groups and raised with TMR feeding formulation until 18, 20 and 22 months old, respectively. In the result, final body weights were 703, 768 and 804 ㎏, and average daily gains were 1.32, 1.32 and 1.27 ㎏, respectively. Dry matter intakes (DMI) were 8.62, 8.94 and 9.24 ㎏. Feed conversion ratio was 6.53, 6.77 and 7.28 for 18, 20 and 22 months old groups. Feed conversion ratio was increased as the fattening periods increased. In yield traits, carcass weight was significantly lower in 18 months old group compared to other groups (p<0.05). The back fat thickness were 8.4, 7.3 and 7.8 ㎜, rib eye area were 70.6, 73.4 and 73.84 ㎠, and the meat yield index was 62.9, 62.5 and 62.1 when slaughtered at 18, 20 and 22 months old, respectively. In the frequency of the yield grade (A:B:C, %), grade B was highest at 20 months old group as 0:75:25. In the quality traits, marbling score, texture and maturity were not different among slaughtering age groups. However, marbling score tended to be increased at 22 months old group. Meat color and fat color were higher at 22 months old group compare to other groups (p<0.05). In the frequency of the quality grade (1+:1:2:3,%), 22 months-old group was the greatest as 12:0:50:38. The income was highest for 20 months old group as 279 thousand wons among the 3 groups. Therefore, the slaughtering ages of Holstein steers may be appropriate at 20 months old.

This study was conducted to investigate the effects of Chromium-Methionine (Cr-Met) chelate feeding for different durations on growth and carcass characteristics in the late fattening stage of Holstein steers. Nine Holstein steers were randomly assigned to three dietary treatments (3 head per treatment) including Non Cr-Met chelate feeding (NCM, av. BW of 433.3 kg), Cr-Met chelate feeding for 2 months (2CM, av. BW of 459.6 kg), and Cr-Met chelate feeding for 4 months (4CM, av. BW of 490.0 kg), respectively. The feeding amount of Cr-Met chelate to an animal was limited to 400 ppb/day. Dry matter intake showed no differences among all the treatments (p>0.05). Average daily gain was also higher in the animals fed Cr-Met chelate diets than NCM (p<0.05). Carcass weights were also observed to be higher in Cr-Met chelate feeding treatments, especially in 4CM compared with other treatments (p<0.05). Although no significant differences were observed on back fat thickness and rib eye area(p<0.05), but 4CM showed much higher effects than NCM and 2CM. Marbling score meat color, fat color, texture, and maturity were not affected by treatments (p>0.05). The variations in meat quality were smaller in 4CM compared to other treatments. 4CM showed higher total and net income than other treatments (p<0.05). Therefore, the current study concluded that Cr-Met chelate supplementation for 4 months could increase daily gain, carcass characteristics, and profitability of Holstein steers in the late fattening stage.

This study was conducted to investigate the effects of different levels of soybean curd residue as an ingredient of TMR on growth performance and carcass characteristics of Holstein steers. Twenty four Holstein steers of 7 months age(average body weight 274.6 kg) were randomly allocated to 3 experimental groups, which contained 8animals per group during 15-months feeding trial. The treatments composed of the group fed concentrate and rice straw separately (Control), the group fed TMR containing low levels of soybean curd (T1), the group fed TMR containing high levels of soybean curd residue (T2). Body weight and average daily gain were not significantly different among the treatment groups during the feeding trial periods. Feed intake was not differ among treatment groups, but feed conversion ratio was significantly higher in T2 group compared to T1 group during late fattening stage (p<0.05). However, it was not different in overall average. According to the yield traits, carcass weight of control, T1 and T2 were 466.4, 451.1 and 460.1 kg, respectively. Back fat thickness, rib eye area and yield index were not different among the groups. The marbling score, meat color, texture and maturity in quality traits were not different among the treatment groups, but fat color was significantly higher in T2 group compared to T1 group (p<0.05). The quality grade (1+:1:2:3, NO.) tended to be higher for T1(0:2:1:5) and T2 (0:1:4:3) compared with the control (0:0:3:5). Therefore, these results indicated that TMR with soybean curd residue may be appropriate the growth performance and carcass characteristics of Holstein steers.