• Asian-Australasian Journal of Animal Sciences
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• 제20권11호
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• pp.1713-1720
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• 2007

Influence of -110, +110, +220 and +330 mEq/kg of dry matter (DM) dietary cation-anion difference (DCAD) on growth performance of Thalli lambs were examined in a randomized complete block design. Four DCAD diets were randomly allotted to four groups, with ten lambs in each group. A linear increase in nutrient intake was recorded with increasing DCAD level. The digestibilities of nutrients were higher in lambs fed -110 DCAD diet than those fed +110, +220 and +330 DCAD diets. Lambs fed +330 DCAD diet had higher nitrogen balance than those fed -110 and +110 DCAD diets. Blood pH and serum $HCO_3$ increased with increasing DCAD level. Serum chloride was higher in lambs fed -110 DCAD diet, while serum (Na+K)-(Cl+S) increased linearly with increasing DCAD level. Serum calcium increased with decreasing DCAD level while serum magnesium and phosphorus remained unaffected. Lambs fed -110 DCAD diet had higher Ca balance than those fed +110, +220 and +330 DCAD diets. Urine pH increased with increasing DCAD level. Lambs fed +220 and +330 DCAD diets gained more weight than those fed -110 and +110 DCAD diets. In conclusion, increased DCAD level not only increased the dry matter intake but also improved the weight gain of growing Thalli lambs.

• Asian-Australasian Journal of Animal Sciences
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• 제33권6호
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• pp.941-948
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• 2020

Objective: This study was carried out to determine the effects of elevated dietary cation and anion difference (DCAD) on dry matter intake (DMI) and ruminal fermentation pattern in lactating dairy goats under tropical conditions. Methods: Ten dairy goats were divided into two groups of five animals each. The groups received diets at different DCAD levels, either a control diet (22.81 mEq/100 g dry matter [DM], DCAD-23) or a DCAD-39 diet (39.08 mEq/100 g DM, DCAD-39). After parturition, DMI and water intake were recorded daily. Ruminal fluid and urine were collected, and nutrient digestibility measurements were carried out at 8th weeks postpartum (PP-8). Blood samples were collected at PP-4 and PP-8 to measure plasma leptin. Results: Dry matter intake/body weight (DMI/BW) at PP-8 of the animals fed the DCAD-39 diet was significantly higher than those fed with DCAD-23 diet (p<0.05). Animals fed with DCAD-39 consumed more water than those fed DCAD-23 over 24 h, particularly at night (p<0.05). Ruminal pH, acetate concentration, and urinary allantoin excretion increased with the DCAD-39 diet, whereas ruminal butyrate concentration was lower with the DCAD-39 diet. On the other hand, other ruminal parameters, such as total volatile fatty acid concentration, propionate molar proportion and acetate/propionate average ratio, were not affected by increased DCAD supplementation. Apparent digestibility was improved by increased DCAD supplementation. Plasma leptin concentration was higher with DCAD supplementation. Conclusion: When feeding goats with DCAD-39 under tropical conditions, an increase in DMI was associated with improved apparent digestibility of nutrients, ruminal fermentation and microbial protein synthesis. An increase in plasma leptin concentration could not explain the effect of high DCAD on DMI.

• Asian-Australasian Journal of Animal Sciences
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• 제25권4호
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• pp.486-495
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• 2012

Twenty four periparturient cows were used to determine the effects of DCAD on acid-base balance, plasma and urine mineral concentrations, health status, and subsequent lactation performance. Each group of 12 cows received either a diet containing -100 DCAD or +100 DCAD for 21 d prepartum. Both anionic and cationic groups were divided into two groups, one received a +200 DCAD and the other +400 DCAD diet for 60 d postpartum. Prepartum reduction of DCAD decreased DMI, urinary and blood pH, urinary concentrations of Na or K and increased plasma and urinary Ca, Mg, Cl and S. Also cows fed -100 DCAD diet consumed the most dry matter in the first 60 d after calving. Postpartum +400 DCAD increased milk fat and total solid percentages, urinary and blood pH and urinary Na and K concentrations, but urinary Ca, P, Cl and S contents decreased. Greater DMI, FCM yields were observed in cows fed a diet of +400 DCAD than +200 DCAD. No case of milk fever occurred for any diets but feeding with a negative DCAD diet reduced placenta expulsion time. In conclusion, feeding negative DCAD in late gestation period and high DCAD in early lactation improves performance and productivity of dairy cows.

• Asian-Australasian Journal of Animal Sciences
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• 제32권4호
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• pp.599-606
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• 2019

Objective: The present study was carried out to evaluate the effect of high dietary cation and anion difference (DCAD) rations on diurnal variations in eating and meal patterns, water intake and urination patterns in dairy goats fed under high ambient temperature (HTa). Methods: Ten crossbred dairy goats during peri-parturition period were selected and divided into two groups of five animals each. Experimental diets were control DCAD (control, 22.8 mEq/100 g dry matter [DM]) and high DCAD (DCAD, 39.1 mEq/100 g DM). The composition of two diets consisted of 44% corn silage and 56% concentrate. From the 2nd week to 8th week postpartum, goats were fed ad libitum twice daily either with the control or DCAD total mix ration with free access to water. The spontaneous eating and drinking patterns were determined. Results: The environmental conditions in the present experiment indicated that goats were fed under HTa conditions (average peak THI = 85.2) and were in heat stress. In addition to the typical HTa induced tachypnoea in both groups, the respiratory rate in the DCAD group was significantly higher than the control group (p<0.05). Although the goats from both groups showed comparable level of eating, drinking and urination during experiment, the meal pattern and water intake were different. High DCAD apparently increased eating and meal patterns compared with the control. At week 8 postpartum, goats from high DCAD group had significant (p<0.05) bigger meal size and longer meal duration. Moreover, high DCAD appeared to increase night-time water intake (p<0.05). Conclusion: Both meal pattern and night-time drinking effects of DCAD suggested that feeding with high DCAD ration may alleviate the effect of heat stress in dairy goat fed under HTa conditions.

• Bulletin of the Korean Chemical Society
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• 제25권6호
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• pp.900-906
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• 2004

An RPLC-postcolumn detection method has been developed for the fluorimetric determination of dichloroacetamide (DCAD) in water. After ammonia and DCAD were separated on a $C_{18}$ nonpolar stationary phase with 2.5% methanol-0.02 M phosphate buffer at pH 3, the column eluant was reacted with post column reagents, o-phthaldialdehyde (OPA) and sulfite ion at pH 11.5, to produce a highly fluorescent isoindole fluorophore, which was measured with a fluorescence detector ( ${\lambda}_{ex}$ = 363 nm, ${\lambda}_{em}$ = 425 nm). With the optimized conditions for RPLC and the postcolumn derivatization, the calibration curve was found to be linear in the concentration ranges of 0.5 and 20 ${\mu}$M for DCAD, and the detection limit for DCAD was 0.18 ${\mu}$M (23${\mu}$g/L). This corresponded to 18 pmol per 100 ${\mu}$L injection volume for a signal-to-noise ratio of 3, and the repeatability and reproducibility of this method were 1.0% and 2.5% for five replicate analyzes of 2 ${\mu}$M DCAD, respectively. The degradation yields DCAD to ammonia were 94 and 99%, and the percent recoveries of DCAD from 4 and 6 ${\mu}$M DCAD-spiked tap water were shown mean more than 97%.

• Asian-Australasian Journal of Animal Sciences
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• 제31권5호
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• pp.677-685
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• 2018

Objective: The objective of the present study was to determine ammonium chloride tolerance of lactating dairy cows, by examining effects of negative dietary cation anion difference (DCAD) induced by ruminal ammonium chloride infusion on performance, serum and urine minerals, serum metabolites and enzymes of lactating dairy cows. Methods: Four primiparous lactating Chinese Holstein cows fitted with ruminal cannulas were infused with increasing amounts (0, 150, 300, or 450 g/d) of ammonium chloride in a crossover design. The DCAD of the base diet was 279 mEq/kg dry matter (DM) using the DCAD formula (Na + K - Cl - S)/kg of DM. Ammonium chloride infusion added the equivalent of 0, 128, 330, and 536 mEq/kg DM of Cl in treatments. According to the different dry matter intakes (DMI), the resulting actual DCAD of the four treatments was 279, 151, -51, and -257 mEq/kg DM, respectively. Results: DMI decreased linearly as DCAD decreased. Yields of milk, 4% fat-corrected milk, energy-corrected milk, milk fat, and milk protein decreased linearly as DCAD decreased. Concentrations of milk protein and milk urea nitrogen increased linearly with decreasing DCAD. Concentration of Cl- in serum increased linearly and concentration of PO43- in serum increased quadratically as DCAD decreased. Urine pH decreased linearly and calculated urine volume increased linearly with decreasing DCAD. Linear increases in daily urinary excretion of $Cl^-$, $Ca^{2+}$, $PO_4{^{3-}}$, urea N, and ammonium were observed as DCAD decreased. Activities of alanine aminotransferase, aspartate aminotransferase, and ${\gamma}-glutamyl$ transferase in serum and urea N concentration in serum increased linearly as DCAD decreased. Conclusion: In conclusion, negative DCAD induced by ruminal ammonium chloride infusion resulted in a metabolic acidosis, had a negative influence on performance, and increased serum enzymes indicating potential liver and kidney damage in lactating dairy cows. Daily ammonium chloride intake by lactating dairy cows should not exceed 300 g, and 150 g/d per cow may be better.

• Journal of Animal Science and Technology
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• 제48권4호
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• pp.555-562
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• 2006

본 실험은 여름철 착유우의 체온조절 능력, 산유량 및 유성분에 미치는 양이온－음이온 균형 (dietary cation-anion difference : DCAD)과 반추위 보호지방이나 나이아신의 첨가 효과를 구명하기 위하여 수행하였다. 30두의 비유중기 홀스타인 착유우 (DIM 134±12.4, 산유량 23.4±2.3kg/d)를 세개의 군으로 구분하여 배치하였다 (처리당 10두). 시험축은 후리스톨 우사에서 사육되었고, 우사에는 41cm 직경의 송풍팬이 부착되어 풍속 4 m/s로 송풍되도록 하였다. 시험축은 7월부터 8월까지 2개월동안 3가지의 시험사료를 섭취할 수 있도록 하였으며, 시험사료는 양이온－음이온 균형이 +15와 +30인 사료에 보호지방 첨가, 나머지 사료는 반추위 보호지방이나 보호지방과 나이아신을 보충하였다. 시험기간 중 7월에는 최대 온도가 28.5℃로 시험축이 약간의 고온스트레스를 받는 정도로 유지되었으나, 시험이 진행되어 8월에는 특징적인 심한 고온스트레스를 보였고, 최대온도가 32.4℃에 도달하였으며, THI는 74.0이었다. 건물, 조단백질, 가소화양분총량 섭취량은 양이온－음이온 균형 수준과 반추위 보호 지방이나 나이아신에 의하여 영향을 받지 않았으나, 산유량은 반추위 보호지방과 나이아신을 첨가한 사료를 섭취한 착유우에서 무첨가구에 비하여 높았다(P<0.05). 반추위 보호지방이나 반추위 보호지방과 나이아신을 동시에 첨가한 처리간에는 산유량의 차이는 없었다. 그리고 유지방과 직장온도도 양이온－음이온 균형 수준과 반추위 보호지방이나 나이아신 첨가에 의한 차이는 나타나지 않았다. 그러나 호흡률은 반추위 보호지방이나 반추위 보호지방과 나이아신을 동시에 첨가한 처리에서 낮게 나타났다 (P<0.05). 본 연구의 결과는 높은 수준의 양이온－음이온 균형 (+30)과 반추위 보호지방과 나이아신을 첨가하는 경우에 여름철인 7월과 8월 고온기에 홀스타인 착유우의 고온스트레스를 줄이고, 호흡율을 감소시키며, 산유량을 증가시킬 수 있음을 나타내었다.

• Bulletin of the Korean Chemical Society
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• 제34권6호
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• pp.1783-1790
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• 2013

A simultaneous analytical method has been developed for the fluorimetric determination of haloacetonitriles (HANs) [dichloroacetonitrile (DCAN), trichloroacetonitrile (TCAN), dibromoacetonitrile (DBAN), haloacetamides [dichloroacetamide (DCAD), and trichloroacetamde (TCAD)] in drinking water by using the combined on-line perconcentration/reversed phase liquid chromatography (RPLC)-postcolumn detection system. This on-line perconcentration system was achieved by employing a precolumn packed with a commercial solid phase extraction (SPE) sorbent for the enrichment and purification of the target analytes. The haloacetonitriles and haloacetamides were separated on CN analytical column in a 7.5% methanol-0.02 M phosphate buffered mobile phase at pH 3. The column effluents were reacted with postcolumn reagents of ophthaldialdehyde (OPA) and sulfite ion at pH 11.5, to produce a highly fluorescent isoindole fluorophore, which were measured with a fluorescence detector. Under the optimized conditions for RPLC and the postcolumn derivatization system all of the coefficient of determination of the standard calibration curves for the target analytes were over 0.99 and had a linear range from 5 to 100 ${\mu}g/L$. The detection limits showed 1.6 ${\mu}g/L$ for DCAD, 0.1 ${\mu}g/L$ for TCAD, 0.6 ${\mu}g/L$ for DCAN, 1.6 ${\mu}g/L$ for TCAN and 1 ${\mu}g/L$ for DBAN, and the recoveries were ranged from 64 to 99% except for DCAD with precisions less than 4.9% in distilled water, and from 72(${\pm}4%$) to 116%(${\pm}2%$) in tap water.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2007년도 정기학술발표대회 논문집
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• pp.618-621
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• 2007

현행 실행되고 있는 하자관리의 경우 마감전단계, 시공자 사전점검, 입주자 사전점검시기에만 주로 하자점검을 하고 각각의 하자 데이터는 서로 연관성이 없다. 그리고 기존의 하자관리 연구의 경우 주로 하자를 분류함에 있어 공종 및 공종별 하자 유형으로 하자데이터를 분류하였다. 이에 본 연구에서는 하자 데이터를 분류하는 기준에 하자의 부위를 추가 하여 하자 데이터를 분류하였다. 또한 부위별 하자관리에 의한 상시 하자관리 체계 방안으로 Web을 기반으로 하는 PDA와 3DCAD이용을 제안하였다.

• 대한수의학회지
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• 제52권1호
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• pp.57-59
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• 2012

In this study, we investigate the status of calcium (Ca) homeostasis at parturition in three dairy farms (I, II, and III), Heilongjiang, China. Twenty multiparous Holstein cows from each farm were randomly assigned to this experiment. The dietary cation-anion difference (DCAD) was 91 mEq/kg of DM for farm I, 152 mEq/kg of DM for farm II, and 85 mEq/kg of DM for farm III. Incidence of hypocalcemia was above 75% and urine pH was above 7.25 at calving in each farm. Compared to other farms, cows in farm II that fed the greatest positive DCAD had the lowest concentration of serum Ca, the highest concentration of serum PTH, and the greatest urine pH at calving (p < 0.05). However, there was not significant difference in serum 1,25-dihydroxy-vitamin D and hydroxyproline concentration of the cows among three farms. This is the first study to confirm that hypocalcemia is very prevalent at calving in Chinese dairy farms, and the high positive DCAD is a major risk factor that results in hypocalcemia at calving, which may reduce ability of the cow to maintain Ca homeostasis.