• Asian-Australasian Journal of Animal Sciences
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• 제24권6호
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• pp.766-773
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• 2011

The objective of the present study was to examine whether yaks possess any adaptive mechanisms of nitrogen (N) metabolism to survive in the harsh foraging environment of the Qinghai-Tibetan Plateau. A grazing experiment on native alpine meadows was conducted to determine availability of herbage biomass and body weight (BW) change of yaks over the year, followed by two indoor feeding trials to investigate adaptation mechanisms of N metabolism in yaks fed at similar intake level to grazing conditions. Three castrated males of each of three genotypes; yak (Bos grunniens), indigenous cattle (Bos taurus) and their crossbred - cattleyak (Bos taurus male${\times}$Bos grunniens female), were used in the housed trials. Results showed that: i) Monthly herbage biomass production and daily grazing intakes by yaks over the year ranged from 220 to 4,664 kg DM per ha, and 1.90 to 8.50 kg DM, respectively. For about seven months each year, yaks suffer from malnutrition as a result of inadequate pasture conditions; ii) Urinary N excretion and N retention by yaks were significantly affected by feeding level, and yaks had a lower (p<0.05) average daily urinary N excretion (0.39 g/kg $BW^{0.75}$) and a greater (p<0.05) N retention (-0.09 g/kg $BW^{0.75}$) than indigenous cattle (0.47 and -0.16 g/kg $BW^{0.75}$, respectively). Fasting daily urinary N excretion was greater (p<0.05) for indigenous cattle than yaks (353 vs. 248 mg/kg $BW^{0.75}$). Purine derivative N excretion and purine derivative N index (PNI) increased with increasing feeding level, while the value of PNI was greater (p<0.05) for yaks and cattleyak (0.11 and 0.12, respectively) than for indigenous cattle (0.09) during the feeding trials. These results suggest that yaks could rely, in part, on the recycling of N to adapt to the harsh forage environment on the Qinghai-Tibetan Plateau.), were used in the housed trials. Results showed that: i) Monthly herbage biomass production and daily grazing intakes by yaks over the year ranged from 220 to 4,664 kg DM per ha, and 1.90 to 8.50 kg DM, respectively. For about seven months each year, yaks suffer from malnutrition as a result of inadequate pasture conditions; ii) Urinary N excretion and N retention by yaks were significantly affected by feeding level, and yaks had a lower (p<0.05) average daily urinary N excretion (0.39 g/kg $BW^{0.75}$) and a greater (p<0.05) N retention (-0.09 g/kg $BW^{0.75}$) than indigenous cattle (0.47 and -0.16 g/kg $BW^{0.75}$, respectively). Fasting daily urinary N excretion was greater (p<0.05) for indigenous cattle than yaks (353 vs. 248 mg/kg $BW^{0.75}$). Purine derivative N excretion and purine derivative N index (PNI) increased with increasing feeding level, while the value of PNI was greater (p<0.05) for yaks and cattleyak (0.11 and 0.12, respectively) than for indigenous cattle (0.09) during the feeding trials. These results suggest that yaks could rely, in part, on the recycling of N to adapt to the harsh forage environment on the Qinghai-Tibetan Plateau.

• Asian-Australasian Journal of Animal Sciences
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• 제7권4호
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• pp.547-554
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• 1994

This paper presents the effects of supplementary feeding and internal parasites on the growth rates of female weaner goats raised under improved management. A completely randomized $3{\times}3{\times}2$ factorial design was used. Factors were genotype (Thai native: TN, 75% TN $\times$ 25% Anglo-Nubian: An and 50% TN $\times$ 50% AN), feeding grazing only, low (1.0% BW/d) and high (1.5% BW/d) supplementation and parasite control (undrenched and drenched). It was shown that native goats had significantly (p<0.05) higher growth rates than did the cross-bred goats from 12-24 weeks of the trial. The growth rate of goats grazing improved pasture depended on the amount of concentrate offered as a supplement. There was no significant difference in growth rates between undrenched and drenched goats. There was no interaction effect on growth rates between the treatments. Drenched goats had significantly (p<0.01) lower egg counts per gram of gastro-intestinal nematode than did undrenched goats. There was no significant difference between the treatments for blood constituents (total protein, haemoglobin, packed cell volume, eosinophils, lymphocytes, monocytes and basophils).

• The Korean Journal of Ecology
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• 제23권2호
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• pp.181-185
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• 2000

This study was carried out to see whether Gastrophysa viridula (Degeer) (Coleoptera : Chrysomelidae) could be used as a biological control agent for Rumex obtusifolius L., with human manipulation of the beetle population. The study was consisted of three experimental sets : Wet-Dry experiment (the wet weight Vs dry weight relationship of Rumex obtusifolius L.), Greenhouse feeding experiment, and Field experiment. There was a significant correlation between the total wet and dry weight of Rumex obtusifolius as follows : Total dry weight : -0.23542+ (0.17514${\times}$Total wet weight) ($R^2$=0.9317, p=0.047, T=16.927 (dF=21)). In the Greenhouse feeding experiment, the result was very promising. The relationship between the density unit of the beetles and the growth of the plant is given below (20 day) : Plant growth =105.8+(-34.4${\times}$Density unit) ($R^2$=0.76, p=0.13). A repeated introduction of the beetle population into the field vegetation of R. obtusifolius from April to October is suggested to see the beetle's grazing ability on the plant. This study shows that the potential grazing power of the beetle on Rumex obtusifolius was enough to defoliate the plants, but it was able to recover from its root reserves. The practical question remains as to whether repeated additions (by man) of the beetles to Rumex obtusifolius could eliminate them.

• 한국양식학회지
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• 제15권2호
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• pp.79-86
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• 2002

This study is the first attempt to understand the feeding physiology of a sea-urchin larva on a red-tide dinoflagellate. Fifteen day old larvae of S. intermedius capture C. polykrikoides cells by localized reversal of ciliary beats. No failure to transporte the algal cells from theciliated band to mouth and no rejection at the mouth suggest that C. polykrikoides has no feeding deterrence to S. intermedius larvae. The trend obtained for the clearance rate of S. intermedius larvae is similar to that of other sea urchin larvae. Thus, the clearance rate decreased as the algal concentration increased. Maximum clearance rate of S. intermedius on C. polykrikoides was 17.7 $\mu l$/larva/hr. Ingestion rate rapidly increased at lower algal concentrations and saturated at higher concentrations. There was no inhibition in ingestion rate at the highest prey concentration of ca. 3000 cells/ml. Maximum ingestion rate of S. intermedius on C. polykrikoides was 131 ngC/larva/d, which is higher than that reported for the larvae of the mussel Mytilus gal-lotrovincialis, but lower than that of the ciliate Strombidinopsis sp. The grazing rate, calculated by combining the field data on algal abundances with experimental data on ingestion rate, suggests that due to its low abundance, sea urchin Iarva has no significant grazing impact on C. polykrikoides population.

• 한국초지조사료학회지
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• 제35권3호
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• pp.225-231
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• 2015

Improving current pasture productivity by precision management requires practical tools to collect site specific pasture biomass data. Recent developments in unmanned aerial vehicle (UAV) technology provide cost effective and real time applications for site specific data collection. For the mapping of herbage biomass (BM) on a hill pasture, we tested a UAV system with digital cameras (visible and near-infrared (NIR) camera). The field measurements were conducted on the grazing hill pasture at Hanwoo Improvement Office, Seosan City, Chungcheongnam-do Province, Korea on May 17 and June 27, 2014. Plant samples were obtained from 28 sites. A UAV system was used to obtain aerial photos from a height of approximately 50 m (approximately 30 cm spatial resolution). Normalized digital number (DN) values of Red and NIR channels were extracted from the aerial photos and a normalized differential vegetation index using DN ($NDVI_{dn}$) was calculated. The results show that the correlation coefficient between BM and $NDVI_{dn}$ was 0.88. For the precision management of hilly grazing pastures, UAV monitoring systems can be a quick and cost effective tool to obtain site-specific herbage BM data.

• 한국초지조사료학회지
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• 제30권2호
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• pp.151-158
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• 2010

본 연구는 제주조릿대의 성장단계별 영양소 함량을 분석하고 말에서의 소화율을 검정하여 말 사료자원으로써의 활용가치를 평가하고, 제 주조릿대 군락지 내 말 방목에 따른 제주조릿대의 생산성, 생육특성, 주변 식생의 변화 등을 구명하기 위해 수행되었다. 제주조릿대를 구초 (1년생)와 신초 (당년생)의 성장단계로 분류하여 조단백질, NDF, ADF 및 무기물 함량을 분석했다. 제주마 5두를 이용 제주조릿대 구초와 신초의 전분채취법을 이용한 외관상 소화율을 검정했다. 제주조릿대 자연 군락지 내에 말 2두를 2년 동안 4회에 걸쳐 방목하면서 생육특성, 생산량을 조사했다. 제주조릿대의 조단백질 함량 (DM 기준)이 구초 줄기와 잎에서 각각 $4.8{\pm}0.4$, $12.2{\pm}1.1%$, 신초 줄기와 잎에서는 각각 $8.0{\pm}0.8$, $16.6{\pm}1.0%$로 나타났다. 일반 목초류에 비해 제주조릿대의 Fe, Mn, Zn 함량이 특이적으로 높았다. 제주조릿대의 외관상 건물 소화율은 구초와 신초에서 각각 $36.4{\pm}0.8$, $47.2{\pm}1.2%$로 신초가 구초보다 소화율이 높은 것으로 분석되었다. 말 방목 이전에 비해 방목을 거듭 할수록 제주조릿대 초장 (86.9 vs 33.1 cm), 엽장 (19.3 vs 16.0 cm), 엽폭 (5.3 vs 3.7cm) 등이 감소하였으며, 이에 따른 생산량 및 밀도 (145.6 vs 52.8개/$m^2$)도 줄어들었다. 본 연구 결과, 제주조릿대는 사료가치가 양호하여 사료자원으로의 활용이 가능하나, 방목이 지속될수록 세력이 약화되어 생산량 및 밀도가 감소하고 있어 이용 방법에 대한 추가 연구가 필요하다.

• 한국초지조사료학회지
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• 제5권3호
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• pp.207-211
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• 1985

본(本) 시험(試驗)은 비음(庇陰)(Light: 100, 80, 60, 40, 20%) 및 시비(施肥) (다비(多肥); N30kg-$P_2O_5\;35kg-K_2O\;30kg$, 보비(普肥); N20kg-$P_2O_5\;25kg-K_2O\;20kg$, 소비(少肥); N10kg-$P_2O_5\;15kg-K_2O\;10kg$) 조건하(條件下)에서 재배(栽培)된 혼합목초(混合牧草) 및 orchardgrass와 나지(裸地)에서 재배(栽培)된 혼합목초(混合牧草) 및 혼합야초(混合野草)를 재래산양(山羊)에 공시(供試)하여 비음(庇陰)이 채식기호성(採食嗜好性)에 미치는 영향과, 비음도(庇陰度) 50%의 임간초지(林間草地)와 나지초지(裸地草地)에서 재래산양을 공시하여 비음(庇陰)이 방목습성(放牧習性)에 미치는 영향을 구명하였다. 본(本) 시험(試驗)은 $1983{\sim}1984$년 까지 충남대학교 시험포장에서 실시되었으며 얻어진 시험결과(試驗結果)는 다음과 같다. 1. 임간재배(林間栽培) 목초(牧草)의 건물(乾物)섭취량, R.I.I 및 Touch number는 비음도(庇陰度) 및 시비수준(施肥水準)에 따라 영향을 받았으며 비음도(庇陰度) 및 시비수준(施肥水準)이 증가함에 따라 $NO_3-N$(%)가 증가된 반면에 soluble carbohydrate(%)는 감소되는 경향이었다. 따라서 임간초지(林間草地)에서는 가축(家畜)의 기호성(嗜好性) 감소에 따른 초지이용(草地利用)의 저하가 염려되며 특히 비음도(庇陰度) 60% 및 다비조건하(多肥條件下)에서는 nitrate stress가 예상된다. 2. 임간초지(林間草地)의 방목습성(放牧習性)은 일반초지(一般草地)에 비하여 채식시간(採食時間)이 증가되고 일중(日中)의 주(主) 채식시간(採食時間)도 편중됨이 없이 계속해서 채식하는 경향을 나타낸다. 따라서 임간초지(林間草地)의 이용(利用)은 비음(庇陰)의 특성(特性)을 고려하여 8월(月) 고온기(高溫期) 집중이용(集中利用)하는 것이 효과적(效果的)이라 생각된다.

• Asian-Australasian Journal of Animal Sciences
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• 제20권9호
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• pp.1374-1388
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• 2007

Three experiments were conducted to investigate the hypothesis that cows grazing on pasture produce the highest proportion of c-9 t-11 CLA in milk fat and no further increase can be achieved through supplementation of diets rich in linoleic acid, such as full-fat extruded soybeans or soybean oil. In experiment 1, 18 lactating Holstein cows were used in a randomized complete block design with measurements made from wk 4 to 6 of the experiment. In experiment 2, three cannulated lactating Holstein cows were used in a $3{\times}3$ Latin square design. Each period was 4 wk with measurements made in the final wk of each period. Cows in both experiments were assigned at random to treatments: a, conventional total mixed ration (TMR); b, pasture (PS); or c, PS supplemented with 2.5 kg/cow per day of full-fat extruded soybeans (PES). In both experiments, feed intake, milk yield, milk composition, and fatty acid profile of milk and blood serum were measured, along with fatty acid composition of bacteria harvested from rumen digesta in experiment 2. In experiment 3, 10 cows which had continuously grazed a pasture for six weeks were assigned to two groups, with one group (n = 5) on pasture diet alone (PS) and the other group (n = 5) supplemented with 452 g of soy oil/cow per day for 7 d (OIL). In experiment 1, cows in PS treatment produced 350% more c-9, t-11 CLA compared with cows in TMR treatment (1.70 vs. 0.5% of fat), with no further increase for cows in PES treatment (1.50% of fat). Serum c-9, t-11 CLA increased by 233% in PS treatment compared with TMR treatment (0.21 vs. 0.09% of fat) with no further increase for cows in PES treatment (0.18% of fat). In experiment 2, cows in PS treatment produced 300% more c-9 t-11 CLA in their milk fat compared with cows in TMR treatment (1.77 vs. 0.59% of fat), but no further increase for cows in PES treatment (1.84% of fat) was observed. Serum c-9, t-11 CLA increased by 250% for cows in PS treatment compared with cows in TMR treatment (0.27 vs. 0.11% of fat), with no further increase for cows in PES treatment (0.31% of fat). The c-9, t-11 CLA content of ruminal bacteria for cows in PS treatment was 200% or more of TMR treatment, but no further increase in bacterial c-9, t-11 CLA for cows in PES treatment was observed. Supplementation of soy oil in experiment 3 also did not increase the c-9 t-11 CLA content of milk fat compared with cows fed a full pasture diet (1.60 vs. 1.54% of fat). Based on these findings, it was concluded that supplementing with feeds rich in linoleic acid, such as full-fat extruded soybeans or an equivalent amount of soy oil, to cows grazing perennial ryegrass pasture may not increase milk fat c-9 t-11 CLA contents.

• 한국해양학회지:바다
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• 제9권1호
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• pp.40-49
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• 2004

강원도 삼척 호산해역에서 해조장의 회복에 결정적 역할을 할 것으로 짐작되는 둥근성게(Strongylocentrotusnudus) 개체군에 대한 생태학적 연구를 수행하였다. 2002년 6월의 예비연구를 통해 조하대에 3개 실험구(인공해조장. 갯녹음지역, 자연해조장)를 설정하고, 8월, 10월, 12월에 둥근성게의 분포와 섭식률, 포식압, 포식자 조합을 추정하였다. 둥근성게의 서식 밀도는 자연해조장에서 가장 낮았으나, 각경(test diameter)의 중위수는 가장 큰것(Kruskal-Wallis test, 8월, p<0.001; 10월, p=0.036)으로 나타났다. 둥근 성게의 먹이 섭식률을 추정하기 위한 실험(enclosure cage experiment)은 자연해조장에서 수행되었으며, 8월과 10월에 각각 160, 13.8 mg seaweed/g sea urchin/day로 추정되었다. 둥근성게에 대한 상대적인 포식압의 실험구 간 비교를 위해 수행된 포박실험 (tethering experiment)으로부터 자연해조장의 포식압이 다른 두 실험구에 비해 상대적으로 높은 것으로 나타났다. 실험 도중 현장에서 관찰된 포식자는 대부분 무척추동물인 것으로 나타났으며 어류 포식의 증거는 찾을 수 없었다. 죽은 성게나 산 성게를 담은 통발을 이용하여 포식자 조합을 파악하기 위한 실험을 하였다. 둥근성게의 포식자는 복족류 Neptuned arthritica와 별불가사리 Asterina pectinifera, 집게류 Pagurus cf. samuelis, 그리고 게류에 속하는 Atergatis integerrimus 등이며, 집게류인 Paguristes barbatus와 게류인 Actaea subglobosa도 가능성이 있는 포식자인 것으로 추정되었다 실험구 간 대비되는 관찰 결과로부터 (1)성게의 낮은 서식 밀도와 관련된 요인은 포식압이며, (2) 이는 조사 해역의 백화 현상의 발생, 유지와 낮은 포식압 간 가능한 상관관계를 제시하는 것으로 해석되었다.

• Asian-Australasian Journal of Animal Sciences
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• 제19권4호
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• pp.521-525
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• 2006

The present study was undertaken to evaluate the effect of flushing of ewes with concentrate pellets just before the mating season on their nutrient utilization and reproductive performance on farms. Forty-eight Malpura ewes, 1-5 years old were randomly divided into 2 groups of 24 each (G1and G2). Ewes in both the groups were grazed on natural rangeland from 07.00 to 18.00 hr followed by night shelter in animal shed. G1 ewes were maintained on sole grazing while G2 ewes, in addition to grazing, received concentrate pellets at the rate of 1.5% of their body weight. The mean biomass yield of the community rangeland was 0.46 ton DM/hectare. The intakes of DM (g/kg $W^{0.75}$), DCP (g/kg $W^{0.75}$) and ME (MJ/kg $W^{0.75}$) were higher (p<0.01) in G2 as compared to that of G1 being 86.5, 10.2 and 1.15 and 57.5, 4.7 and 0.75, respectively. The digestibility of DM, OM, CP, NDF and hemicellulose were also higher (p<0.01) in G2 as compared to that of G1 being 57.2, 76.7, 78.9, 51.9 and 81.6 and 50.8, 68.7, 68.4, 45.4 and 74.4, respectively. The conception rate was higher (79.2%) in flushed ewes as compared to that of non-flushed (66.7%). Five of the pregnant ewes died and another 5 aborted in G1 while in G2, 5 ewes aborted with no mortality. The lambing was higher (73.7%) in G2 than that in G1 (37.5%). The birth weight of lambs was higher (p<0.05) in G2 (3.47 kg) than that in G1 (2.95 kg). Further, the birth weight of male lambs was higher (3.28) than that of female lambs (3.14). It is concluded that the biomass yield of the community rangeland in semi-arid region of India is low and insufficient to meet the nutrient requirement of ewes prior to mating season. However, concentrate supplementation at the rate of 1.5% of body weight to ewes during this critical stage enhanced their plane of nutrition, reproductive performance, body condition and birth weights of lambs.