• Asian-Australasian Journal of Animal Sciences
• /
• 제15권6호
• /
• pp.806-811
• /
• 2002

A 90 d study was designed to investigate the effects of rumen undegradable protein (RUP) and a mixture of Cu, Zn and Mn proteinate (CZMP) on milk yield and composition and ovarian functions during rainy months. Twenty four Holstein${\times}$ indigenous cows in their 2nd and 3rd lactation were randomly allocated to total mixed rations (TMR) containing soy bean meal (SBM) as a source of rumen degradable protein (RDP), SBM plus CZMP, and formalin treated SBM (FSBM) as a source of RUP. Maximum and minimum temperature humidity index during the experimental period were 83.6-84.7 and 75.4-76.1. There were no differences (p>0.05) in intakes of dry matter, crude protein and net energy and in contents of butterfat, lactose and minerals. Cows on TMR containing FSBM not only lost less weight (-278, -467 and -433 g/d) with more intake of RUP (0.92, 0.58 and 0.59 kg/d) but also produced more milk (19.27, 18.23 and 18.13 kg/d) and 4% fat corrected milk (18.57, 17.57 and 17.51 kg/d) with more protein (3.06, 2.81 and 2.80%), solids-not-fat (8.69, 8.38 and 8.38%) and less milk urea N (9.3, 15.4 and 15.0 mg/dl) compared with those on TMR containing SBM and SBM+CZMP, respectively (p<0.01). However, cows on TMR containing SBM and SBM+CZMP did not differ in these respects (p>0.05). Whereas incidence of cystic ovaries at 20 and 90 d pospartum was less (p<0.01) in cows on TMR containing SBM+CZMP (37.3 and 12.5%) than those on TMR containing SBM (62.5 and 25%), it was nil for cows on TMR containing FSBM. Cows in all three group differed (p<0.01) from each other for the recurrence of first observed estrus with those on TMR containing FSBM having least days (22, 36 and 47 d) compared with their counterpart on TMR containing SBM+CZMP and SBM, repectively. The results suggest that RUP is one of the limiting factors affecting milk yield and its composition and ovarian functions during early lactation of dairy cows in the tropics.

• 한국농림기상학회지
• /
• 제10권1호
• /
• pp.9-16
• /
• 2008

입지유형별 미기후 특성이 임목생장에 미치는 영향을 구명하고자 연구 대상지의 입지유형을 사면방향, 해발고, 그리고 지형특성 등의 총 36가지 유형으로 구분한 후, 각 입지유형별 평년 기후값을 지형기후학적 방법으로 추정한 후, 평년 기후값으로부터 임목생장에 영향을 미칠 것으로 판단되는 17개 기후변수를 입지유형별로 도출하였다. 한편 입지유형별 직경생장, 수고생장, 재적생장에 대한 정보를 얻기 위해 임분조사를 실시했으며, 직경생장량, 수고생장량, 재적생장량의 추정에 적합한 회귀추정식을 17개 기후변수를 사용하여 개발하였다. 입지유형별 직경생장량은 건조지수에 의하여 최적으로 추정할 수 있었다. 건조지수는 총강수량에 대한 연 평균기온의 비에 의하여 계산되기 때문에 강수량이 많아 수분조건이 양호한 입지조건에서 직경생장이 우수한 것으로 나타났다. 한편, 수고생장량은 건조지수와 월 평균 일조시수의 두 기후변수의 조합에 의해 잘 추정되는 것으로 나타났으며, 재적생장량 추정식에 포함된 기후변수는 건조지수와 월 평균상대습도로 밝혀졌다. 결과적으로 입지유형별 직경생장, 수고생장, 그리고 재적생장을 추정하기 위해 사용한 17개 기후변수 중에서 공통적으로 건조지수가 포함되어 입지유형별 임목생장에는 수분조건이 큰 영향을 미치는 것으로 평가된다.

• Asian-Australasian Journal of Animal Sciences
• /
• 제32권9호
• /
• pp.1407-1413
• /
• 2019

Objective: This experiment aimed to investigate the effect of different sources and inclusion levels of dietary fat on productive performance and egg quality in laying hens raised under hot environmental conditions. Methods: A total of 480 Hy-Line Brown laying hens at 31 wk of age were randomly allotted to 1 of 5 experimental diets. The control diet contained 2,800 kcal/kg nitrogen-corrected apparent metabolizable energy with no fat addition. Four additional diets were prepared by adding 2.0% or 4.0% of animal fat (AF) or soybean oil (SO). Energy and nutrient concentrations were consistent among all diets. Diets were fed to hens for 4 weeks. Average daily room temperature and humidity were $26.7^{\circ}C{\pm}1.52^{\circ}C$ and $77.4%{\pm}4.50%$. The heat stress index was approximately 76, indicating that hens were raised under heat stress conditions. Results: Final body weight (BW) was greater (p<0.05) for hens fed diets containing 2.0% or 4.0% AF than for those fed the control diet or diets containing 2.0% or 4.0% SO. The BW gain and feed intake were greater (p<0.05) for hens fed diets containing additional AF or SO than those fed the control diet. Eggshell thickness was the greatest (p<0.05) for hens fed the control diet, but the least (p<0.05) for hens fed diets containing 4.0% SO. Egg yolk color was the greatest (p<0.05) for hens fed the control diet, but the least (p<0.05) for hens fed diets containing 4.0% SO. Conclusion: Inclusion of supplemental fat (AF and SO) in diets exhibits preventative effects on BW loss for hens raised under hot environmental conditions when energy and nutrient concentrations in diets were maintained. The effects were greater for AF than for SO. However, inclusion of supplemental fat in diets decreases eggshell thickness and egg yolk yellowness, possibly due to a reduction in Ca absorption and intake of egg yolk colorants.

• 한국지구과학회지
• /
• 제43권3호
• /
• pp.386-404
• /
• 2022

2011년 4월 29일부터 30일까지 몽골에서 발원한 황사의 영향으로 우리나라는 4일간 전국적으로 고농도의 황사가 관측되었다. 본 연구는 몽골의 황사발원지에서 황사 발생 시 기상 조건과 고농도 황사 사례의 원인 및 특성을 알아보기 위한 것으로, 황사 일기도 자료, 황사감시기상탑 자료, 위성 자료, 후방공기궤적 자료, 관측자료(PM₁₀ 및 광학입자 계수기 자료), ECMWF 재분석 자료를 이용하였다. 분석 결과, 종관 분석에서는 몽골 중부지역에 등압선의 간격이 조밀하게 분포하고 기압경도력이 강해지면서 강풍에 의해 황사가 발원하였다. 황사 발원과 기상 조건의 관계에서 황사 발원 직전에는 10℃ 이상으로 비교적 높은 기온을 나타내다 황사 발원과 동시에 급감하였으며, 상대습도는 약 40% 이하의 낮은 값을 지속적으로 나타내다 황사 발원 후에는 50% 이상으로 급격히 높아지며 황사의 발생이 줄어드는 경향을 보였다. COMS에서 관측된 황사지수는 황사발원지에서는 25 이상을 나타내면서 고농도의 황사가 탐지되었고, 실황에서 목측으로 관측된 지점과 일치하였다. 72시간 후방공기궤적에서는 모두 북서 기류가 한반도로 유입되었고, 5월 2일 흑산도에서는 PM₁₀의 시간평균농도가 1,025 ㎍ m^-3으로 최고 농도를 보였다. 특히 운동학적 연직 분석에서, 상층에서 발달한 기압골과 저기압성 소용돌이도에 의해 지상 저기압이 강화되고 동시에 상승 기류의 발달이 고농도의 황사 발생에 큰 역할을 한 것으로 판단된다.

• 응용통계연구
• /
• 제35권4호
• /
• pp.543-552
• /
• 2022

서리는 표면 근처의 공기의 이슬점 온도가 빙점 이하일 때 수증기가 승화, 응축되어 땅이나 물체에 얼게 되는 작은 얼음 결정체이다. 서리가 내리면 농작물이 직접 피해를 입는다. 농작물이 낮은 온도에 접촉하면 조직이 얼어서 세포막이나 엽록체가 딱딱해지고 파괴되거나 건조한 세포가 죽습니다. 2020년 7월, 세계 최대 커피 생산국인 브라질 미나스제라이스 주에 갑작스러운 영하의 날씨와 서리가 내려 지역 커피 나무의 약 30%가 피해를 입었다. 이로 인해 피해로 커피값이 크게 올랐고, 피해가 심각한 농가는 농작물이 회복되기까지 3년이 걸리기 때문에 2024년에야 커피를 생산할 수 있다. 본 논문에서는 심한 서리가 내리는 것을 방지하기 위해 기상청이 제공하는 서리 발생 데이터와 기상관측 데이터를 이용해 서리를 예측하려고 했다. 관측 지점의 고도 및 풍속, 온도, 습도, 강수량, 흐림 등의 기상 요인을 반영하여 모델을 구축하였다. XGB, SVM, Random Forest, MLP 모델을 사용하여 다양한 하이퍼 파라미터를 학습 데이터로 적용하여 각 모델에 가장 적합한 모델을 선택하였다. 마지막으로, 결과는 테스트 데이터에서 정확도(acc)와 중요 성공 지수(CSI)로 평가되었다. XGB는 90.4%의 acc와 64.4%의 CSI로 다른 모델에 비해 최고의 모델이었고, SVM은 89.7%의 acc와 61.2%의 CSI로 그 뒤를 이었다. 랜덤 포레스트와 MLP는 약 89%의 acc와 약 60%의 CSI로 비슷한 성능을 보였다.

• Journal of Animal Science and Technology
• /
• 제64권6호
• /
• pp.1046-1062
• /
• 2022

This study investigated the effects of L-glutamine (Gln) supplementation on growth performance, physiological traits, heat shock proteins (HSPs), and gene expression related to muscle and adipose tissue development in Hanwoo steers under heat stress (HS) conditions. Eight Hanwoo steers (initial body weight [BW] 570.7 ± 43.6 kg, months of age 22.3 ± 0.88) were randomly separated into two groups, control and treatment, and supplied with the concentration (1.5% of BW kg/day/head) and rice straw (1.5 kg/day/head). The treatment group were fed the Gln supplementation (0.5% of concentration, as-fed basis) once a day at 08:00 h. Blood samples for the assessment of haematological and biochemical parameters and the separation of peripheral blood mononuclear cells (PBMCs) were collected four times, at 0, 3, 6, and 10 weeks of the experiment. Feed intake was measured daily. BW to analyze growth performance and hair follicle collection to analyze the expression of HSPs were executed four times at 0, 3, 6, and 10 weeks. To analyze gene expression, longissimus dorsi muscle samples were collected by biopsy at the end of the study. As a result, growing performance, including final BW, average daily gain, and gain-to-feed ratio, were not different between the two groups. Leukocytes including lymphocytes and granulocytes, tended to increase in the Gln supplementation group (p = 0.058). There were also no differences in biochemical parameters shown between the two groups, except total protein and albumin, both of which were lower in the Gln supplementation group (p < 0.05). Gene expressions related to muscle and adipose tissue development were not different between the two groups. As temperature-humidity index (THI) increased, HSP70 and HSP90 expression in the hair follicle showed a high correlation. HSP90 in the hair follicle was decreased in the treatment group compared with the control group at 10 weeks (p < 0.05). Collectively, dietary Gln supplementation (0.5% of concentration, as-fed basis) may not be influential enough to affect growth performance and gene expression related to muscle and adipose tissue development in steers. However, Gln supplementation increased the number of immune cells and decreased HSP90 in the hair follicle implying HS reduction in the corresponding group.

• Journal of Animal Science and Technology
• /
• 제65권1호
• /
• pp.132-148
• /
• 2023

Ruminants are the main contributors to methane (CH₄), a greenhouse gas emitted by livestock, which leads to global warming. In addition, animals experience heat stress (HS) when exposed to high ambient temperatures. Organic trace minerals are commonly used to prevent the adverse effects of HS in ruminants; however, little is known about the role of these minerals in reducing enteric methane emissions. Hence, this study aimed to investigate the influence of dietary organic trace minerals on rumen fermentation characteristics, enteric methane emissions, and the composition of rumen bacteria and methanogens in heat-stressed dairy steers. Holstein (n=3) and Jersey (n=3) steers were kept separately within a 3×3 Latin square design, and the animals were exposed to HS conditions (Temperature-Humidity Index [THI], 82.79 ± 1.10). For each experiment, the treatments included a Control (Con) consisting of only basal total mixed rations (TMR), National Research Council (NRC) recommended mineral supplementation group (NM; TMR + [Se 0.1 ppm + Zn 30 ppm + Cu 10 ppm]/kg dry matter), and higher concentration of mineral supplementation group (HM; basal TMR + [Se 3.5 ppm + Zn 350 ppm + Cu 28 ppm]/kg dry matter). Higher concentrations of trace mineral supplementation had no influence on methane emissions and rumen bacterial and methanogen communities regardless of breed (p > 0.05). Holstein steers had higher ruminal pH and lower total volatile fatty acid (VFA) concentrations than Jersey steers (p < 0.05). Methane production (g/d) and yield (g/kg dry matter intake) were higher in Jersey steers than in Holstein steers (p < 0.05). The relative abundances of Methanosarcina and Methanobrevibacter olleyae were significantly higher in Holstein steers than in Jersey steers (p < 0.05). Overall, dietary organic trace minerals have no influence on enteric methane emissions in heat-stressed dairy steers; however, breed can influence it through selective alteration of the rumen methanogen community.

• 한국농림기상학회지
• /
• 제25권4호
• /
• pp.245-257
• /
• 2023

우리나라 대표적인 식량 작물인 벼는 넓은 면적에서 장기간 재배되어 병해충에 대한 저항성이 낮아지고 있다. 대표적인 벼 질병 중 하나인 도열병이 대규모로 발생하면 수확량이 감소하여 조기에 병을 발견하고 방제를 하여야 한다. 하지만 농지 중심에서 도열병이 발생 하면 육안으로 병을 발견하기 어렵다. 드론을 이용한 작물 모니터링 기법은 생육 이상을 탐지하는데 유용하나 언제 발생할지 모르는 도열병 발생을 위해 빈번하게 촬영을 하는 것은 많은 인력과 비용이 소모된다. 본 연구의 목적은 드론, 위성과 같은 원격탐사 자료와 기상자료를 공동 활용하여 벼 도열병을 조기에 탐지하는 것이다. 위성영상은 벼 재배 필지를 추출하는데 유용하였다. 식생지수와 수분지수의 특성을 이용하여 관개가 된 논을 효과적으로 탐지하였다. 이후 기온, 상대습도, 강우일수 자료를 활용하여 벼 도열병 발생위험도를 계산하였다. 도열병 발생위험도가 증가하면 병이 발생할 가능성이 높아진다는 것을 의미하며, 해당 시점에 드론 관측을 수행하였다. 병이 발생한 지점, 병이 발생한 지점과 일반 벼가 혼재되어 있는 지점, 일반 벼 지점에서 분광반사도의 변화를 살펴보았으며, 갈색 병반을 가지는 도열병 특성상 적색과 근적외선 파장대에서 분광반사도의 변화가 급격한 것을 확인하였다. 도열병이 발생한 지점에서는 주변 지점에 비해 식생지수 값이 낮은 군집이 나타났으며, 시계열 드론 영상을 통해 해당 지점으로부터 벼 도열병 확산을 추적하였다. 최종적으로 수확 전 드론 영상을 활용하여 필지별 도열병 발생률에 대한 공간정보를 생산하였다.

• Animal Bioscience
• /
• 제37권5호
• /
• pp.896-907
• /
• 2024

Objective: The potential of aqueous extract of Christ's thorn jujube (Ziziphus spina-christi) leaves (SLAE) to reduce the negative impacts of heat stress on production performance and physiological traits was investigated in dual-purpose layers under subtropical farming. Methods: A total of 200, 25-week-old laying hens (Inshas strain) were randomly assigned to four dietary treatments including SLAE at 0, 2.5, 5.0, and 7.5 mL/kg, respectively. The average temperature-humidity index value was 26.69 during the experimental period. The SLAE contained saponin (0.045%), total flavonoid content of 17.9 mg of quercetin equivalent/100 g and overall antioxidant capacity concentration of 17.9 mg of ascorbic acid equivalent/100 g. Results: The maximum final body weight (BW), BW gain, egg weight, number, and mass occurred at the level of SLAE7.5 inclusion. The egg quality was significantly higher in SLAE groups than in control, and overall, SLAE7.5 had the most favorable influence at 28 and 32 weeks. Liver and kidney function, as well as lipids profile, improved significantly by SLAE inclusion; the lowest concentrations of these parameters were in SLAE7.5 hens. Treatment with SLAE7.5 increased total antioxidant capacity and endogenous antioxidant enzymes compared to control, whereas no effect on superoxide dismutase was noticed. Conclusion: The addition of SLAE at 7.5 mL/kg diet improved egg laying performance and quality, metabolic profiles, and antioxidant status during hyperthermia conditions.

• Asian-Australasian Journal of Animal Sciences
• /
• 제30권4호
• /
• pp.505-513
• /
• 2017

Objective: This study was performed to evaluate whether ambient temperature and dietary glycerol addition affect growth performance, and blood metabolic and immunological parameters, in beef cattle. Methods: Twenty Korean cattle steers ($405.1{\pm}7.11kg$ of body weight [BW], $14.2{\pm}0.15$ months of age) were divided into a conventional control diet group (n = 10) and a 2% glycerol- added group (n = 10). Steers were fed 1.6% BW of a concentrate diet and 0.75% BW of a timothy hay diet for 8 weeks (4 weeks from July 28th to August 26th and 4 weeks from August 27th to September 26th). Blood was collected four times on July 28th, August 11th, August 27th, and September 26th. Results: The maximum indoor ambient temperature-humidity index in August (75.8) was higher (p<0.001) than that in September (70.0), and in August was within the mild heat stress (HS) category range previously reported for dairy cattle. The average daily gain (ADG; p = 0.03) and feed efficiency (p<0.001) were higher in hotter August than in September. Glycerol addition did not affect ADG and feed efficiency. Neither month nor glycerol addition affected blood concentrations of cortisol, triglyceride, or non-esterified fatty acid. Blood concentrations of cholesterol, low-density lipoprotein, high-density lipoprotein, glucose, and albumin were lower (p<0.05) on August 27th than on September 26 th, and blood phosphorus, calcium and magnesium concentrations were also lower on August 27th than on September 27th. Glycerol addition did not affect these blood parameters. Percentages of $CD4^+$ T cells and $CD8^+$ T cells were higher (p<0.05) on July 28th than on August 27th and September 26th. The blood $CD8^+$ T cell population was lower in the glycerol supplemented-group compared to the control group on July 28th and August 27th. Conclusion: Korean cattle may not be significantly affected by mild HS, considering that growth performance of cattle was better in hotter conditions, although some changes in blood metabolic and mineral parameters were observed.