• 한국식품과학회지
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• 제30권3호
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• pp.574-580
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• 1998

유지방을 초임계 이산화탄소로 추출한 후 흡착제를 통과시켜 콜레스테롤이 제거되고, 지방산 조성이 다른 유지방 분획들을 얻기 위하여, 콜레스테롤 흡착능이 있는 것으로 알려진 몇 가지 흡착제를 선택하여, 추출온도 $40^{\circ}C$, 추출압력 276, 345 bar에서 3 또는 4시간 동안 추출하면서 흡착제의 종류별, 입자크기별, 비율별로 추출시간에 따른 유지방의 수율, 콜레스테롤 함량, 지방산 조성을 측정하였다. 흡착제로서 ${\beta}-cyclodextrin,\;talc,\;celite,\;florisil$ 중에서 florisil이 유지방으로부터 콜레스테롤 제거율이 가장 높았다. Florisil의 입자크기별로 콜레스테롤 제거율은 30/60 mesh가 가장 높았으며, 그 다음 100/200, 60/100 mesh순이었다. 유지방에 대하여 흡착제의 비율이 높으면 콜레스테롤 제거율은 높은 반면, 지방의 수율은 감소하였는데, 유지방의 수율을 높이면서 콜레스테롤 제거율을 높이기 위해서는 유지방과 흡착제의 비율은 20:10이 적당하였다. 추출분획물의 지방산 조성을 측정한 결과 저급 지방산들은 초기 추출물 분획들에 농축되었고, 고급 지방산들은 추출잔류물 분획에 농축되었다. 이상의 결과로부터 초임계유체 추출 및 흡착법은 유지방으로부터 콜레스테롤을 제거하는 동시에 저급지방산, 불포화지방산, 버터향, 색소가 농축된 분획 등을 얻을 수 있었다.

• 한국임상수의학회지
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• 제19권1호
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• pp.43-48
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• 2002

This study was performed to investigate the effects of recombinant BST formulation treatment on the milk yield, milk components, mastitis, and general cow health condition when the formulations of retinyl palmitate, cholecalciferol and rBST were administered after the peak period of milk production. The milk yields of treatment groups (Group I, II, III and IV) were increased from 21.5% to 29.0% than that of control group. There was significant difference in milk production between treatment group II, IV and control group (P<0.05). However, there was no significant difference in milk production between treatment group I, III and control group (P<0.05). And the addition of retinyl palmitate and cholecalciferol into rBST formulation did not increase the milk yield. The milk of treatment groups with sustained-release rBST did not show significant difference in milk components (milk fat, protein, lactose, and solid not fat). However, there were minor changes, primarily in fat content of milk, during the first few weeks of rBST administration. There was no incidence of clinical mastitis between rBST treatment groups and control group. Addition of high and medium concentration of retinyl palmitate and cholecalciferol into sustained-release rBST formulation was efficient in reduction of somatic cell count in milk. There was great energy deficit in all treatment groups compared with control group during the early study period. Thus, the body condition score of all treatment groups showed lower value than control group. No evidences of metabolic health problems, such as ketosis, milk fever, and downer cow were observed. Incidence of general lameness did not appear on all treatment groups during 140 days of this study.

• Asian-Australasian Journal of Animal Sciences
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• 제22권4호
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• pp.516-519
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• 2009

This study was conducted to investigate the effects of replacing whole crop corn silage (WCCS) with whole crop rice silage (WCRS) in the total mixed ration (TMR) on nutrient intake, milk yield and its composition in Holstein cows. The Chucheong rice variety (Oryza sativa L. Japonica) and corn (Pioneer 32 P75) were harvested at yellow-ripe stage and were ensiled in round bales and in trench silos, respectively. Two TMR containing either WCCS or WCRS were prepared. These diets were randomly assigned to 16 midlactating Holstein cows (8 cows per treatment) and were fed for 120 days. The first 20 days were used for dietary adaptation and for the next 100 days daily feed intake, milk yield and its composition were recorded. The pH, lactic acid, NDF, ADF, CP, Ca and P contents were similar in WCRS and WCCS. The DM, ash and EE contents of WCRS were greater compared with WCCS. Nutrient (DM, NDF, TDN and CP) intakes were similar in cows fed WCCS- and WCRS-based TMR. Daily and 4% fat corrected milk yield were not affected by the treatments. Milk composition (percent milk fat, protein, lactose and total solids) was similar in cows fed either WCCS- or WCRSbased TMR. The concentration of milk urea N was greater in cows fed WCRS-based TMR than those fed WCCS-based TMR. In conclusion, round-baled WCRS can replace WCCS in the diet of mid- to late-lactating Holsteins without any deleterious effects on feed consumption, milk yield and its composition. The present findings raise the possibility that WCRS can be used as an alternative roughage source in the diets of dairy cows in countries with surplus rice production.

• Asian-Australasian Journal of Animal Sciences
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• 제19권10호
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• pp.1384-1389
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• 2006

Prolactin plays an important role in mammary gland development, milk section initiation and maintenance of lactation, so the bovine prolactin gene is considered as a potential quantitative trait locus affecting milk performance traits in dairy cattle. In this study, to determine the association between prolactin and milk performance traits, the genetic polymorphisms of a part of the prolactin gene were detected in a population of 649 cows of Chinese Holstein Dairy Cattle. Three SNPs in the promoter and one SNP in the intron1 of prolactin were identified, which was A/C (-767), G/T (-485), C/A (-247), and C/T (427), respectively. Statistical results indicated that one of SNP within promote, CHBP2, was significantly associated with milk yield (p<0.01), fat yield (p<0.05), protein yield (p<0.01), and protein percentage (p<0.05). The cows with genotype BB of CHBP2 had significantly higher milk yield (p<0.01), fat yield (p<0.05), and protein yield (p<0.01) than those of cows with genotype AA, while cows with genotype AA showed the highest protein percentage (p<0.05). In addition, based on the nine major haplotypes constructed from the four SNPs, the association analysis between diplotypes and milk performance trait was carried out. Results showed that the least square mean for fat yield of diplotype H2H8 was significantly higher than those of other eleven diplotypes (p<0.05). Our findings implied that CHBP2 and H2H8 of prolactin would be useful genetic markers in selection program on milk performance traits in Holstein Dairy Cattle.

• Journal of Animal Science and Technology
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• 제46권5호
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• pp.773-782
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• 2004

본 연구는 산차와 비유기가 다양한 Holstein 종 56두를 사용하여 사료섭취량과 에너지요구 량을 근거로 개체별 사료에너지요구량의 서열을 설정하고, 이를 3개 우군으로 나누어 각 우군의 상반평균치에 기준하여 자가배합사료(herdmix ration)를 조제한 후 이것을 이용한 사양체계가 비유기 및 산차에 미치는 영향을 관행 사양체계와 switch-over method로 비교하였다. 자가배합사료 급여체계는 전 비유기 동안 산유량과 유지율을 증진시켰으며(P<0.05), 산차별 생산능력도 모든 산차에서 향상되었다(P<0.05). 비유단계별 성적에서는 비유초기와 중기에서 Herd-mix구의 설제산유량(AMY) 및 지방보정유량(FCM)이 유의적으로 증가하였으나(P<0.05) 유지율은 유의차가 없었다. 비유말기에는 AMY, 유지율 및 FCM 모두 Herd-mix구가 관행구에 비하여 증가하였으며 특히 유지율과 FCM이 현저하게 증가하였다(P<0.01). Herd-mix구와 관행구의 FCM 비유지속성은 각각 93.24%와 92.69%로서 Herd-mix구의 비유지속성이 높았으며 비유곡선의 형태도 이상적 추세를 보였다. 유대와 사료비를 고려한 조수익을 산출한 결과 Herd-mix구가 관행구보다 40% 높았다. 결론적으로, 본 연구는 젖소의 에너지요구량과 사료 에너지 농도를 정확히 평가하여 우군을 편성한 후 그 상반평균을 배합목표로 설정하고 사용할원료에 대한 실질적인 평가를 근거로 배합비를 설정하는 것이 산유능력을 향상시킴과 동시에 경제적으로 유려하다는 사실을 입증하였다.

• Asian-Australasian Journal of Animal Sciences
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• 제25권9호
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• pp.1338-1350
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• 2012

This review focuses on the nutritional effects from birth until age at first calving on growth, mammary developmental changes, and first-lactation milk yield in heifer calves. The advancement in the genetic potential and the nutritional requirements of the animals has hastened the growth rate. Genetic selection for high milk yield has suggested higher growth capacity and hence increasing nutritional inputs are required. Rapid rearing by feeding high energy or high concentrate diets not only reduces the age of sexual maturity but also lowers the time period of attaining the age of first calving. However, high energy diets may cause undesirable fat deposition thereby affecting future milk yield potential. Discrepancies exist whether overfed or overweight heifers at puberty can influence the mammary development and future milk yield potential and performance. The data on post-pubertal nutritional management suggested that body weight at calving and post-pubertal growth rate is important in first lactation milk yield. There is a continuous research need for strategic feeding that accelerates growth of dairy heifers without reduction in subsequent production. Nutritional management from birth, across puberty and during pregnancy is critical for mammary growth and for producing a successful cow. This review will mostly highlight studies carried out on dairy breeds and possible available opportunities to manipulate nutritional status from birth until age at first calving.

• Asian-Australasian Journal of Animal Sciences
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• 제15권2호
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• pp.222-237
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• 2002

Effects of high and low levels of feeding with or without protected protein on the performance of lactating goats were studied. Twenty four German Fawn goats either from 1st ($43.37{\pm}3.937$ kg and 2 year old) or 3rd $62.64{\pm}6.783$ kg and 4-5 year old) parity were used for the trial. Feeding levels were 7.2 (I) and 5.2 (II) MJ ME/litre of milk of 3.5% fat in addition to that of the maintenance allowance. At each feeding level, diet had either unprotected (U) or formaldehyde protected (P) soya-meal. Thus, four diets were IU, IP, IIU and IIP, having six animals in each. The diets were composed of hay and pellet (10:4:1 of beet pulp : barley : soya-meal). Effect of feeding level, protein protection, parity, health status and kid number on intake, milk yield, milk composition, growth rate of goats were recorded across the 21 weeks of study. High feeding level resulted increase (p<0.001) in estimated metabolizable energy (ME) and metabolizable protein (MP) availability. Dietary inclusion of protected soya-meal increased (p<0.001) the estimated MP but not the ME availability. Animals in 1st parity ate more (p<0.001) DM (111 vs. 102 g/kg $W^{0.75}$/d) than those in 3rd parity. Animals with twin kids (110 g/kg $W^{0.75}$/d) had higher (p<0.001) DM intake than those with single kid (102 g/kg $W^{0.75}$/d). Fat (4%) corrected milk (FCM) yield was not effected by high (1,924 g/d) or low (1,927 g/d) feeding level but increased (p<0.001) with protected (2,166 g/d) compared with unprotected (1,703 g/d) soya-meal. FCM yield for four dietary combinations were 1,806, 2,078, 1,600 and 2,254 g/d for diets IU, IP, IIU and IIP, respectively. For unit increase (g) in estimated MP availability relative to ME (MJ) intake, FCM yield increased ($1,418{\pm}275.6$) g daily ($r^2$=0.58; p<0.001). Milk fat (3.14 vs. 3.54%; p<0.001) and protein (2.94 vs. 3.04% p<0.05) contents were lower at high than the low feeding level. Protected protein increased (p<0.001) the fat, lactose and net energy (NE) content of milk. Milk urea concentration of 175, 183, 192 and 204 mg/l for diets IU, IP, IIU and IIP, respectively indicated lower RDP content of these diets. The RDP contents were 6.97, 6.70, 7.30 and 6.83 g/MJ of ME for diets IU, IP, IIU and IIP, respectively. Live weight change over the experimental period were 41, 6, 17 and 19 g/d. Absence of any positive response of high feeding was probably due to inefficient rumen fermentation resulting from inadequate RDP supply. Protected protein improved production performance apparently by increasing MP:ME ratio in the absorbed nutrient.

• 한국동물번식학회:학술대회논문집
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• 한국동물번식학회 2001년도 발생공학 국제심포지움 및 학술대회 발표자료집
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• pp.59-59
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• 2001

This study was designed to assess effect of MUN concentration on reproduction performance and monitoring of feeding and fertility management in commercial dairy herd. The mean of milk yield is 26.48±8.38㎏ per day, milk fat 3.80±0.58%, protein 3.13±0.3% MUN 16.68±5.87㎎/㎖ and somatic cell 392,000±77,060㎖. Milk yield has been shown that negative correlation with fat, protein and somatic cell(P〈0.01). The finding of this study was significant relationship between non-pregnant days and MUN concentration. (omitted)

• 한국식품영양과학회지
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• 제23권3호
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• pp.459-465
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• 1994

Performance of a continuous cocurrent supercritical fluid extraction column for processing of anhydrous milk fat (AMF) was determined. The extract loading increased and the extraction yield decreased as the superficial velocity of AMF increased. The maximum solubility of AMF in $CO_2$ at 4$0^{\circ}C$/3,500 psig was 0.0195g/g. The increase of the carbon dioxide density enhanced the solubility of milk fat and decreased the cholesterol concentration in the extract. Three operation conditions, such as recycle , reflux, and temperature gradient of extraction column, were tested. More short-chain fatty acvids were extracted by the reflux operation . Longchain fatty acids and thehighest ratio fo long-chain unsaturated to saturated fatty acids were also obtained in the raffinate phase with refluex.

• Journal of Animal Science and Technology
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• 제65권3호
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• pp.588-595
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• 2023

The aim of this study was to investigate the effects of heat stress on milk traits in South Korea using comprehensive data (dairy production and climate). The dataset for this study comprised 1,498,232 test-day records for milk yield, fat- and protein-corrected milk, fat yield, protein yield, milk urea nitrogen (MUN), and somatic cell score (SCS) from 215,276 Holstein cows (primiparous: n = 122,087; multiparous: n = 93,189) in 2,419 South Korean dairy herds. Data were collected from July 2017 to April 2020 through the Dairy Cattle Improvement Program, and merged with meteorological data from 600 automatic weather stations through the Korea Meteorological Administration. The segmented regression model was used to estimate the effects of the temperature-humidity index (THI) on milk traits and elucidate the break point (BP) of the THI. To acquire the least-squares mean of milk traits, the generalized linear model was applied using fixed effects (region, calving year, calving month, parity, days in milk, and THI). For all parameters, the BP of THI was observed; in particular, milk production parameters dramatically decreased after a specific BP of THI (p < 0.05). In contrast, MUN and SCS drastically increased when THI exceeded BP in all cows (p < 0.05) and primiparous cows (p < 0.05), respectively. Dairy cows in South Korea exhibited negative effects on milk traits (decrease in milk performance, increase in MUN, and SCS) when the THI exceeded 70; therefore, detailed feeding management is required to prevent heat stress in dairy cows.