착색원으로서 감귤껍질의 이용에 관한 연구 1 . 감귤껍질의 건조방법 및 항산화제 처리에 의한 크산토필함량의 변화

정근기,최용규 ( K . K . Jung,Y . K . Choe ) 한국축산학회 1985 한국축산학회지 Vol.27 No.5

The experiment was conducted to investigate the change of xanthophyll content with different drying methods and the ethoxyquin treatment in the laboratory, for the purpose of determing whether the pigment in Satsuma Mandrin peel would be worth of being considered as a supplement of livestock feeds in the future. The flavedo, the outer layers of Satsuma Mandrin peel, was prepared in the laboratory, and 0.01,5% of ethoxyquin was used in this study. The results obtained are summarized as follows: 1. The xanthophyll content in fresh Satsuma Mandrin peel was 397.22 ㎎ per Kg. on dry matter basis. The content in both sun-cured and shadow-cured peels linearly decreased as the drying period proceeded. But the reduction in the sun-cured sample was greater than that in the shadow-cured. The xanthophyll losses on 9th day of drying were 50.2% in the sun-cured and 35.6% in the shadow-cured. 2. The xanthophyll losses during drying in the airforced oven increased with the lapse of drying time. The xanthophyll destruction was greater in 100℃ temperature as compared to 50℃, and a rapid destruction was shown in 3-hour of drying. The losses of xanthophyll in 3 and 24 hours of drying were 32.0 and 57.6% at 50℃, and 45.8 and 61.7% at 100℃, respectively. 3. The ethoxyquin treatment prior to drying prevented xanthophyll destruction of fresh peel for 15-day storage at both 4℃ and 30℃. Storage at 4℃ was less destructive than at 30℃, but the effect of ethoxyquin treatment was more prominent at storage temperature of 30℃ than 4℃. 4. The results suggest that Satsuma Mandrin Peel can be used as a pigmentation source of broiler ar layer ration. But studies on xanthophyll components, industrial drying method and storage conditions are required prior to commercial application.

한우 육증산을 위한 비육촉진제에 관한 연구 2 보 . Monensin 첨가가 한우비거세우의 비육 능력 및 제 1 위내 성상에 미치는 영향

정근기,이학철,손제영,서영석,임경순,함태수 ( K . K . Jung,H . C . Lee,J . Y . Son,Y . S . Sye,K . S . Lim,T . S . Ham ) 한국축산학회 1980 한국축산학회지 Vol.22 No.5

This experiment was conducted to determine the effects of monensin on feedlot performance and volatile fatty acids production in the rumen of fattening bulls of Korean native cattle. Twelve bulls of Korean native cattle averaging 235 ㎏ initially were randomly assigned in groups with 6 animals per pen (9m x 10m) for 280-day experiment. The bulls were fed ad lithium concentrate rations with and without 30 ppm monensin, and the cut rice straw as roughage was mixed with the concentrates at the rate of 10%. Average daily gain for the first stage (112 days), the second stage (168 days), and for the entire period (280 days)was improved by 19.8, 20.5, and 20.2%, respectively, by monensin. Feed conversion for the first stage, the second stage, and the entire period was improved by 16.8, 15.3, and 15.5%, respectively, by monensin. Also, DCP and TDN per ㎏ gain were improved with monensin by 17.6 and 16.8 for the first stage, 15.0 and 15.2% for the second stage, 15.4 and 15.4% for the entire period, respectively. Feed consumption of monensin group tended to be increased slightly compared that of non-monensin group regardless of fattening stages. Ruminal pH and total VFA concentration were not affected by monensin. Molar percent of propionate was greatly increased (p$lt;.01) with monensin feeding and acetate (p$lt;.01) and butyrate decreased markedly. As a result, acetate to propionate ratio was decreased to 32.5%. Monensin did not greatly influence carcass characteristics. However, monensin group tended to have somewhat lower dressing percent, more marbling score, and larger rib-eye area. Rumen parakeratosis, abomasum erosion, and urinary calculi in the bladder were found in all groups. Although there was no large difference between both groups. more urinary calculi were observed in the control than the monensin group. These results indicate that monensin in of positive value as a feed additive in fattening hull rations for Korean native cattle.

한우 육증산을 위한 비육촉진제에 관한 연구 1 보 . Monensin 첨가가 홀스타인 비거세우의 비육능력 및 제1 위내성상 ( 胃內性狀 )에 미치는 영향

정근기,이학철,손제영,서영석,임경순,함태수 ( K . K . Jung,H . C . Lee,J . Y . Son,Y . S . Sye,K . S . Lim,T . S . Ham ) 한국축산학회 1980 한국축산학회지 Vol.22 No.5

Eight holstein bulls averaging 244.1 ㎏ in initial body weight were utilized in two treatments to study the effects of monensin on growth rate, feed efficiency, carcass characteristics and ruminal volatile fatty acids production in an outdoor drylot conditions. The treatment groups were fed ad libitum either 0 or 30 ppm monensin supplemented in concentrates, for 280-day feeding period. The cut rice straw as a only roughage was mined with the concentrates at the rate of 10%. During 112 days of the first stage, monensin improved daily gain 17%.(p$lt;.05), feed conversion 9%, and 11% and 10% in DCY and TDN per ㎏ gain, respectively. Throughout 280 days of tire entire period, monensin group showed 8% improvement in gain but had no improvement io feed conversion and DCP and TDN per ㎏ gain. Feed consumption tended to be higher as tire fattening stages progressed. Ruminal pH and total VFA concentration were unchanged by monensin, Molar percents of acetate and butyrate were reduced and that of propionate increased markedly with monensin. As a result, the acetate to propionate ratio was narrowed.

반추가축의 사료 첨가제로서 Polyether 계 항생물질의 사용효과와 작용기작

정근기 ( K . K . Jung ) 한국영양사료학회 1988 韓國營養飼料學會誌 Vol.12 No.1

거세가 한우 및 홀스타인 비육우의 도체등급에 미치는 영향

정근기(K . K . Jung),김대곤(D . G . Kim),성삼경(S . K . Sung),최창본(C . B . Choi),김성겸(S . G . Kim),김덕영(D . Y . Kim),최봉재(B . J . Choi),윤영탁(Y . T . Yun) 한국축산학회 1996 한국축산학회지 Vol.38 No.3

The study was conducted to investigate the effect of castration on the carcass grade of Hanwoo and Holsteins reared under the same feed and feeding condition. The carcass grading scores were measured by the Korean and Japanese carcass grading standards. The results were compared with respect to Hanwoo and Holstein by sex and Hanwoo and Holstein steers by age. In both grading systems, backfat and lougissimus dorsi of Hanwoo were thicker and larger than those of Holsteins. Steers of both breeds showed thicker backfat and smaller longissinaus dorsi area compared to bulls. Much better carcass yield grade was obtained from Hanwoo than from Holstein, and from bulls than from steers. Hanwoo steers showed significantly higher marbling degree than Hanwoo bulls. As Hanwoo steers aged, backfat thickness and longissimus dorsi area increased. Carcass quality grade of Hanwoo steers increased as age advanced but no apparent changes were found in Holstein steers. When Korean carcass grading standard was applied to judging carcass grade, the steep of Hanwoo resulted in better grade quality of carcasses but a lower quantity of carcass as age increased. Especially, Japanese carcass standard gave better grades with respect to carcass quantity a regardless of breeds and age compared with the Korean standard. In conclusion, the results presented indicate that castration and extended feeding periods (at least 17 months in Holstein and 24 months in Hanwoo) are essential to produce high quality beef, and modification of the current Korean carcass grading standard is necessary to fit carcass characteristics of Hanwoo steers.

율무 , 염주 , 수수 - 수단그래스 교잡종 , 옥수수의 사료가치평가

정근기(K . K . Jung),배동호(D . H . Bae),이석순(S . S . Lee) 한국축산학회 1987 한국축산학회지 Vol.29 No.4

Feed values of a local variety of adlay (Coix lachryma jobi var. mayuen (ROMAN STAPE)) and Job`s tears (C. lachryma jobi L.) were compared with those of a sorghum-sudangrass hybrid (Pioneer 988) and a corn hybrid (Kwangok) at different growth stages. 1. Crude protein content of adlay and Job`s tears at flowering stage and that of sorghum-sundangrass hybrid at heading stage were similar. Crude protein content of the 1st cut forage was higher than that of the 2nd cut, although they were cut at the similar growth stages in all species. Crude protein of corn harvested at the yellow ripe stage was similar to that of the 2nd cut of adlay and Job`s tears. 2. Crude fiber, CWC, ADF, cellulose, lignin, and silica contents of adlay and Job`s tears were higher but hemicellulose content was lower compared to those of corn. 3. The in vitro dry matter digestibility (IVDMD) was greater in the order of corn $gt; sorghum-sundangrass hybrid $gt; Job`s tears $gt; adlay and IVDMD of the 1 st cut forages was higher than that of the 2nd cut. 4. Lactate content of adlay, Job`s tears, and sorghum-sundangrass hybrid silages was lower but butyrate content was higher compared to those of corn silage. Adlay and Job`s tears silages cut 40 days after flowering stage contained higher lactate and acetate but lower butyrate compared to those cut at flowering stage. Quality of sorghum-sudangrass hybrid silage was intermediate between that of adlay silage cut at flowering stage and 40 days after flowering stage. 5. As plant growth stage advanced, crude protein content and IVDMD of adlay and Job`s teats decreased, but crude fiber, CWC, ADF, and cellulose contents increased. The content of hemicellulose was not significantly changed. At the same growth stages dry matter production and IVDMD of adlay was lower and ADF content was higher compared to those of Job`s tears.

사료첨가제로서의 비소제에 관한 연구 1 . 비소제의 첨가수준이 Broiler 의 성장율 및 사료효율에 미치는 영향

정근기 ( K K Jung ),성삼경 ( S K Sung ),민병준 ( B J Min ) 한국축산학회 1972 한국축산학회지 Vol.14 No.4

This experiment was conducted to observe the effect of 3-vitro-4-hydroxyphenylarsonic acid on the growth rate and feed efficiency of broilers. For the experiment, 540 baby chicks of Indian River broiler type were raised for the period of 7 weeks in three different groups. The results obtained are summarized as follows; 1. The levels of adding 3-vitro-4-hydroxyphenylarsonic acid in the diet were not effective for the growth stimulation, but improved the feed efficiency. Symptoms of toxicity resulting from dietary arsenical were not found. 2. For the feed efficiency, there was highly significant difference between 0.009% 3-vitro-fed group and two other groups of 0% and 0.005%. Although no difference was recognized between 0.005% 3-vitro-fed group and the control, 0.005% group resulted in a slight improvement in comparison to the control. 3. The feed cost required for 1㎏ gain was the cheapest for 0.009% 3-nitro-fed group. There was little difference observed between 0.005% and the control groups. 4. Another attempt should be made for further evidence of the effect of an arsenical on the body gain which was not improved in this experiment.

율무종실 , 율무겨 및 율무대의 사료가치

정근기(K . K . Jung),배동호(D . H . Bae),이석순(S . S . Lee) 한국축산학회 1987 한국축산학회지 Vol.29 No.5

In order to evaluate the nutritive values of seeds, hulls plus bran, and stovers of mature adlay plants (Coix lachryma jobi var. mayuen), chemical composition and digestibility were determined. The six Corriedale rams weighing 50-60Kg were used for digestibility determination. The results were compared with those of other crops listed in the Composition Tables of Korean Feedstuffs. 1. Crude fiber, crude ash, lignin, and silica contents in adlay seeds were higher, but dry matter digestibility was lower than those of other cereal seeds. Crude protein content in adlay seeds was 13.g% and it was similar with that of barley or wheat seeds. TDN and DCP in adlay seeds were 60.8% and 9.7%, respectively, nd similar with those of buckwheat and Japanese millet. 2. Crude fiber, NDF, lignin, and silica contents in hulls plus ran of adlay was higher, but digestibility was lower compared with bran of other cereal crops except crude fat. TDN and DCP in hulls plus bran of adlay were 37.7% and 3.1%, respectively, and were higher than those in rice hulls, lower than those: in barley or wheat bran, and similar to those in hulls plus bran of Italian millet. 3. Feed value in terms of chemical composition of adlay stover was higher than that of rice or barley straw and similar to that of corn stover. TDN and DCP in adlay stalk were 39.9% and 3.4%, respectively and higher than those of other cereal crop straws.

사료의 단백질 및 에너지 수준이 New Hampshire 웅추의 성장율 , 사료효율과 에너지 대사율에 미치는 영향

정근기 ( K K Jung ),안병홍 ( B H Ahn ),박상문 ( S M Park ),한인규 ( Han I K ),유한웅 ( H W Yu ) 한국축산학회 1970 한국축산학회지 Vol.12 No.1

This experiment was carried out to study the effect of the level of dietary protein and energy on the growth rate, feed efficiency and energy metabolizability of 270 New Hampslaire male chicks for 8 weeks. The results obtained are summarized as follows; 1. The chicks fed 23% of dietary protein and 1,300 ㎉ of energy per pound in the starter ration obtained the best result (p$lt;0.01) in the body weight gain. 2. The amount of diet consumed by the chicks fed 23% level of protein and 1,200 ㎉ of energy per pound was higher than other groups of chicken. However, feed efficiency was significantly (p$lt;0.01) improved by the chicks fed high protein-high energy ration. 3. Protein utilization, nitrogen retention and metabolizable energy value has been significantly (P$lt;0.01) improved by the chicks fed the lowest dietary protein level (17%) with the highest energy level (1,400 ㎉/lb) 4. Feed cost required per ㎏ gain of chicks was cheapest when the dietary level of protein and energy was 23%-1,200 ㎉.

농후사료내 중탄산소오다의 첨가수준이 면양의 기호성 , 영양소 이용율 및 제 1 위내 발효성상에 미치는 영향

정근기(K . K . Jung),배동호(D . H . Bae),이수기(S . K . Lee) 한국영양사료학회 1997 韓國營養飼料學會誌 Vol.21 No.2