A meta-analysis on effects of supplementing low-quality roughages with foliages from browses and tree fodders on intake and growth in sheep     

Amlan K. Patra   《Livestock Science》2009,121(2-3):239-249

A meta-analysis of data obtained from previous studies was conducted to understand the responses of foliage supplementation on intakes of basal DM (BDMI) and total DM (TDMI), and daily gain (ADG). Thirty-four published studies containing 223 treatments and 1127 sheep met criteria for inclusion in the meta-analysis. Major predictive variables considered were percentages of foliages in diet (SD), CP in foliages (PS), NDF in foliages (FS), NDF in forages (FB), CP in basal roughages (PB), CP in diet (PD) and foliage CP intake (SPI). TDMI (g/d) increased quadratically (P < 0.001) with increasing PS, FS, SPI (R² = 0.66), PB, SD (R² = 0.58) and PD (R² = 0.73). The maximal response of TDMI were 778 g/d at 42% of SD, 894 g/d at 19.8% PD, 893 g/d at 148 g/d SPI and 749 g/d at 26.4% PS (P < 0.001; R² = 0.58, 0.73, 0.66, and 0.37, respectively). BDMI increased quadratically with increasing SD, PD and PB, but decreased quadratically (P < 0.001) with increasing PS (P < 0.001; R² = 0.07). The breakpoint of BDMI was 570 g/d at 6.58% of PD in the diet (P < 0.001, R² = 0.28). Overall, BDMI responded at very low level of SD in the diet, peaking at 7.6% SD with BDMI of 572 g/d (P < 0.001, R² = 0.72). However, when PB was less than 3%, the maximal BDMI was 489 g/d at foliage levels of 25.7%. When PB was between 3 and 6%, maximal BDMI was at 13% of foliage in the diet and the basal forage intake of 597 g/d; whereas, BDMI decreased linearly with SD when PB was greater than 6%. BDMI (g/d) decreased quadratically when foliage CP percentages were lesser than 10%, but increased quadratically with PS when foliage CP percentages were greater than 10%. ADG responded positively and quadratically to PS, SPI, SD, PD and TDMI (g/d) and the relationships were moderate to high. However, ADG (g/d) decreased linearly with increasing FS (P < 0.001, R² = 0.35). The maximal ADG was 42 g/d at 43% of SD, 41 g/d at 9.4% PD, 42 g/d at 53 g/d SPI, 35 g/d at 25% PS and 46 g/d at TDMI of 889 g/d (P < 0.001; R² = 0.74, 0.84, 0.74, 0.29 and 0.74, respectively). It is concluded that the interactions of quality and quantity of foliage supplements and quality of basal forages affect intakes of basal and total DM, and growth in sheep.  相似文献   

诸葛菜试管苗的光合特性及其对CO2浓度升高的响应   总被引：2，自引：0，他引：2  

吴沿友  李国祥  刘建  张红萍  吴德勇 《安徽农业科学》2006,34(23):6098-6099

用Li-840 CO2/H2O气体分析仪对诸葛菜试管苗的光合特性及其对CO2升高的响应进行研究。结果表明:诸葛菜试管苗的光合速率日变化不大,午间没有明显的“午休”现象。在不同光源下实际光合速率的比较,在相同的光强下LED-红光下的试管苗的光合速率最高,LED-蓝光次之。正常大气条件下,LED-蓝光在70μmol/(m2.s)光强下的诸葛菜试管苗的CO2饱和点为5 058μmol/mol,CO2补偿点为266μmol/mol。  相似文献   

不同砧木对藤稔葡萄光合特性的影响   总被引：1，自引：0，他引：1  

马玉坤  贾永芳  马静芳 《河南农业科学》2009,(10)

以少毛变叶葡萄191(LDP-191)、LN33、巨峰为砧木,藤稔为接穗,利用CI-310便携式光合测定仪对在自然条件下藤稔葡萄3种嫁接苗和自根苗的净光合速率、蒸腾速率、气孔导度、光合有效辐射和胞间CO2浓度进行了测定。结果表明:3种嫁接苗与自根苗在晴天的净光合速率的日变化均呈双峰曲线,且3种嫁接组合的净光合速率明显比自根苗的净光合速率高;藤稔自根苗的日均气孔导度明显高于藤稔/LDP-191、藤稔/LN33;不同砧木嫁接的藤稔葡萄光合特性有明显差异,而LDP-191砧木与自根苗相比除净光合速率外其他光合指标均有显著性差异,说明LDP-191砧木对藤稔葡萄是较好的砧木。  相似文献   

黄土高原地质灾害气象预报预警模型研究新思路   总被引：2，自引：0，他引：2  

高维英  李明  杜继稳  王雁林 《安徽农业科学》2010,38(23):12588-12591

利用黄土高原47年降雨型地质灾害资料和相对应降雨资料,采用统计方法建立诱发地质灾害日综合雨量方程,得出崩塌和滑坡启动值、加速值、临灾值的临界日综合雨量。考虑地质灾害风险区划、降雨影响系数、日综合雨量,以高时空分辨率自动气象站降雨观测资料和定量降雨预报预警为基础,建立地质灾害逐时动态日预报和逐时预警相互衔接的精细化、无缝隙地质灾害预报预警模型。通过实例检验表明将降雨型地质灾害动态预报模型和预警模型结合起来应用,提高预报时效,效果更好。  相似文献   

基于动态干旱指数的区域干旱识别系统研究     

王俊  胡继超  袁学所  吴有华 《安徽农业科学》2010,38(30):17162-17163

利用历年逐日降水量、蒸发量等资料,引用一种动态干旱指数,通过比较干旱指数计算值和干旱等级判别标准来判别干旱的发展;然后,基于动态干旱指数,运用VC＋＋计算机编程语言和Access数据库开发了一套安徽省江淮分水岭地区动态干旱识别系统。这对该地区干旱预测与预警具有重要的指导作用和应用价值。  相似文献   

白三叶叶片荧光特性对水分胁迫的响应     

韩建秋 《农业科学与技术》2010,11(3)

[目的]从生理角度研究白三叶(Trifolium repens)叶片叶绿素荧光参数对水分胁迫的响应.[方法]以白三叶品种"海发"为供试材料,设置75%(无胁迫,CK)、50%(轻度胁迫,LD)和25%(重度胁迫,HD)3个土壤含水量水平对植株进行培养,测定水分胁迫对一系列叶绿素荧光参数的影响,并进行统计学分析.[结果]土壤相对含水量为75%和50%时,白三叶叶片叶绿素荧光参数受到的影响不大,说明白三叶在这2种水分条件下能够正常生长;土壤相对含水量为25%时,初始荧光后极显著高于CK和LD处理,原初光能转化效率(Fv/Fm)、PS Ⅱ电子传递量子产量(φPS Ⅱ)和光化学猝灭系数显著降低.[结论]白三叶在重度干旱(HD)条件下,生理机能遭到破坏,不能正常生长,表现出旱害症状.  相似文献   

基于最小二乘支持向量机的参考作物潜在蒸散量估计   总被引：1，自引：0，他引：1  

陈大春  曹伟  雷晓云 《新疆农业大学学报》2011,(5):431-436

建立了以气象因子为输入变量,以Penman-Monteith公式计算所得的参考作物潜在蒸散量（ET0）为输出变量的最小二乘支持向量机（LSSVM）ET0预报模型。与以同样资料为基础的人工神经网络模型（ANN）进行对比研究表明,LSSVM模型比ANN模型精度高,且效率高、泛化能力强,是ET0预报方法的有益补充。  相似文献   

The Effect of Angiotensin‐Converting Enzyme Inhibitors of Left Atrial Pressure in Dogs with Mitral Valve Regurgitation     

T. Ishikawa  R. Tanaka  S. Suzuki  Y. Miyaishi  H. Akagi  Y. Iino  R. Fukushima  Y. Yamane 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2010,24(2):342-347

Background: Despite many epidemiological reports concerning the efficacy of angiotensin‐converting enzyme (ACE) inhibitors in dogs with mitral regurgitation (MR), the hemodynamic effects of ACE inhibitor administration have not been fully evaluated. Objectives: To document left atrial pressure (LAP) in dogs with MR administered ACE inhibitors, in order to obtain interesting information about daily LAP changes with administration of ACE inhibitors. Animals: Five healthy Beagle dogs weighing 9.8 to 14.2 kg (2 males and 3 females; aged 2 years). Methods: Experimental, crossover, and interventional study. Chordae tendineae rupture was induced, and a radiotelemetry transmitter catheter was inserted into the left atrium. LAP was recorded for 72 consecutive hours during which each of 3 ACE inhibitors—enalapril (0.5 mg/kg/d), temocapril (0.1 mg/kg/d), and alacepril (3.0 mg/kg/d)—were administered in a crossover study. Results: Averaged diurnal LAP was significantly, but slightly reduced by alacepril (P= .03, 19.03 ± 3.01–18.24 ± 3.07 mmHg). The nightly drops in LAP caused by alacepril and enalapril were significantly higher than the daily drops (P= .03, ?0.98 ± 0.19 to ?0.07 ± 0.25 mmHg, and P= .03, ?0.54 ± 0.21–0.02 ± 0.17 mmHg, respectively), despite the fact that the oral administrations were given in the morning. Systolic blood pressure (122.7 ± 14.4–117.4 ± 13.1 mmHg, P= .04) and systemic vascular resistance (5800 ± 2685–5144 ± 2077 dyne × s/cm⁵, P= .03) were decreased by ACE inhibitors. Conclusions and Clinical Importance: ACE inhibitors decrease LAP minimally, despite reductions in left ventricular afterload. ACE inhibitors should not be used to decrease LAP.  相似文献   

Comparison between linseed expeller and canola expeller on concentrate intake,and circulating inflammatory mediators in Holstein calves     

《动物营养（英文）》2020,6(1):47-53

The objective of this study was to compare the effect of linseed and canola expeller on average daily weight gain (ADG), concentrate intakes, incidence of diarrhea, serum haptoglobin, interleukin (IL)-1, and resolvin-E1 in female Holstein calves from birth to weaning. A sample size of 20 calves per group was calculated and were randomly allocated at the time of birth. Linseed group (LIN) was fed a starter with linseed expeller, while canola group (CAN) received a similar concentrate, but with canola expeller. Both expellers were included at a rate of 25% dry matter (DM) basis of the starter. Pasteurized waste milk was fed twice a day until weaning. Calves were weighed at birth, 30, and 60 d of age. Starter intake was evaluated daily from 5 to 60 d. A blood sample was obtained at birth, 14, 28, 35, and 49 d of age, and bovine serum resolvin-E1, haptoglobin, and IL-1 were assayed by commercial enzyme-linked immunosorbent assay (ELISA) kits. Incidence of diarrhea and the duration of the events were also recorded. The effect of the interaction group by time on body weight (BW) and starter intake was not significant (P > 0.05). Average daily gains (ADG) from 0 to 60 d for CAN and LIN groups were 0.680 and 0.675 kg/d (P > 0.05), respectively. Incidences of diarrhea were 25% and 45% for CAN and LIN groups, respectively (P = 0.18). LIN group had greater concentrations of IL-1 at d 21, haptoglobin at d 7, and resolving-E1 at d 14 and 49 than CAN group, respectively. It is concluded that BW at weaning, ADG, and concentrate intakes were not different between groups fed starters containing linseed or canola expeller (25% inclusion). The concentrations of cytokines and haptoglobin were the greatest in LIN group.  相似文献   

水稻光合日变化与内生节奏的关系   总被引：15，自引：0，他引：15  

邓仲篪 《中国水稻科学》1994,8(1):9-14

 1986-1990年以水稻原丰早、837等为材料研究了水稻的光合日变化及其与内外因素的关系。水稻的光合日变化呈典型的双峰曲线。光合日变化与气孔开度日变化基本上是同步的。叶面喷水和磷、钾溶液，可减缓光合午睡的程度，但未见午睡消失。延迟见光，短时间的反光周期处理或全光照处理，不改变光合日变化原有的时间节奏。长时间反光周期或全日照处理，则适应形成新的光合日变化规律。说明水稻光合日变化与内生节奏的调节有关。  相似文献